feat: implement per-member reading progress tracking for shared books (#30)

Backend (apps/groups):
- ReadingGroup model: named groups linked to EBooks with creator tracking
- GroupMembership model: user-group association with member/admin roles
- MemberProgress model: per-member progress with section tracking,
  percentage, time_spent, privacy toggles, and device-position preservation
- ReadingGroupViewSet: CRUD, join/leave, members list, progress endpoints
- GET /api/groups/{id}/members/progress/ — all members' progress
  (public: section label only; own: full detail; private: stubbed)
- PATCH /api/groups/{id}/progress/ — update own progress with auto-
  percentage calculation from section boundaries
- GET /api/groups/{id}/progress/summary/ — admin dashboard with
  averages, started/finished counts, and per-member details
- Permissions: IsGroupMember, IsGroupAdmin

Frontend:
- Groups list page (/groups) with create modal and book selector
- Group detail page (/groups/:id) with progress and admin summary tabs
- Progress bar visualization per member with privacy-aware display
- Admin stat cards (total members, started, finished, avg progress, avg time)
- Navigation link from Library header

Shared:
- ReadingGroupSummary and MemberProgressPublic types
- API endpoint constants for groups routes

Closes #30

backend/apps/groups/admin.py

@@ -1,38 +1,23 @@
 from django.contrib import admin
 
-from apps.groups.models import (
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
-    GroupMeeting,
-    GroupMembership,
-    NotificationPreference,
-    PaceNotification,
-    ReadingGroup,
-)
 
 
 @admin.register(ReadingGroup)
 class ReadingGroupAdmin(admin.ModelAdmin):
-    list_display = ["name", "created_by", "created_at"]
+    list_display = ["name", "ebook", "created_by", "created_at"]
-    search_fields = ["name"]
+    search_fields = ["name", "ebook__title", "created_by__email"]
 
 
 @admin.register(GroupMembership)
 class GroupMembershipAdmin(admin.ModelAdmin):
-    list_display = ["user", "group", "role", "joined_at"]
+    list_display = ["group", "user", "role", "joined_at"]
     list_filter = ["role"]
+    search_fields = ["user__email", "group__name"]
 
 
-@admin.register(GroupMeeting)
+@admin.register(MemberProgress)
-class GroupMeetingAdmin(admin.ModelAdmin):
+class MemberProgressAdmin(admin.ModelAdmin):
-    list_display = ["group", "title", "target_section_label", "scheduled_at"]
+    list_display = ["user", "group", "current_section", "percentage", "time_spent_seconds", "is_public", "updated_at"]
-    list_filter = ["group"]
+    list_filter = ["is_public"]
-
+    search_fields = ["user__email", "group__name"]
-
-@admin.register(NotificationPreference)
-class NotificationPreferenceAdmin(admin.ModelAdmin):
-    list_display = ["user", "pace_notifications_enabled", "reminder_enabled", "frequency"]
-
-
-@admin.register(PaceNotification)
-class PaceNotificationAdmin(admin.ModelAdmin):
-    list_display = ["user", "meeting", "status", "created_at"]
-    list_filter = ["status"]

backend/apps/groups/apps.py

@@ -5,4 +5,3 @@ class GroupsConfig(AppConfig):
     default_auto_field = "django.db.models.BigAutoField"
     name = "apps.groups"
     verbose_name = "Reading Groups"
-    label = "groups"

backend/apps/groups/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 5.1.7 on 2026-06-20 19:22
+# Generated by Django 5.1.7 on 2026-06-20 19:21
 
 import django.db.models.deletion
 from django.conf import settings
@@ -11,27 +11,10 @@ class Migration(migrations.Migration):
 
     dependencies = [
         ('books', '0003_readingprogress_epub_location'),
-        ('users', '0001_initial'),
         migrations.swappable_dependency(settings.AUTH_USER_MODEL),
     ]
 
     operations = [
-        migrations.CreateModel(
-            name='NotificationPreference',
-            fields=[
-                ('user', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, primary_key=True, related_name='notification_preference', serialize=False, to=settings.AUTH_USER_MODEL)),
-                ('pace_notifications_enabled', models.BooleanField(default=True)),
-                ('reminder_enabled', models.BooleanField(default=True)),
-                ('frequency', models.CharField(choices=[('daily', 'Daily'), ('weekly', 'Weekly')], default='daily', max_length=16)),
-                ('created_at', models.DateTimeField(auto_now_add=True)),
-                ('updated_at', models.DateTimeField(auto_now=True)),
-            ],
-            options={
-                'verbose_name': 'Notification Preference',
-                'verbose_name_plural': 'Notification Preferences',
-                'db_table': 'groups_notification_preference',
-            },
-        ),
         migrations.CreateModel(
             name='ReadingGroup',
             fields=[
@@ -39,9 +22,9 @@ class Migration(migrations.Migration):
                 ('name', models.CharField(db_index=True, max_length=256)),
                 ('description', models.TextField(blank=True, default='')),
                 ('created_at', models.DateTimeField(auto_now_add=True)),
-                ('book', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='reading_groups', to='books.book')),
+                ('updated_at', models.DateTimeField(auto_now=True)),
                 ('created_by', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='created_groups', to=settings.AUTH_USER_MODEL)),
-                ('ebook', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='reading_groups', to='books.ebook')),
+                ('ebook', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='reading_groups', to='books.ebook')),
             ],
             options={
                 'verbose_name': 'Reading Group',
@@ -50,50 +33,11 @@ class Migration(migrations.Migration):
                 'ordering': ['-created_at'],
             },
         ),
-        migrations.CreateModel(
-            name='GroupMeeting',
-            fields=[
-                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
-                ('title', models.CharField(blank=True, default='', max_length=512)),
-                ('scheduled_at', models.DateTimeField(db_index=True)),
-                ('target_section', models.PositiveIntegerField(default=0, help_text='Target chapter/section index to reach by this meeting')),
-                ('target_section_label', models.CharField(blank=True, default='', help_text="Human-readable label for the target section (e.g. 'Section 3')", max_length=512)),
-                ('created_at', models.DateTimeField(auto_now_add=True)),
-                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='meetings', to='groups.readinggroup')),
-            ],
-            options={
-                'verbose_name': 'Group Meeting',
-                'verbose_name_plural': 'Group Meetings',
-                'db_table': 'groups_meeting',
-                'ordering': ['scheduled_at'],
-            },
-        ),
-        migrations.CreateModel(
-            name='PaceNotification',
-            fields=[
-                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
-                ('status', models.CharField(choices=[('pending', 'Pending'), ('sent', 'Sent'), ('dismissed', 'Dismissed')], default='pending', max_length=16)),
-                ('current_section', models.PositiveIntegerField(default=0)),
-                ('target_section', models.PositiveIntegerField(default=0)),
-                ('ahead_behind_delta', models.IntegerField(default=0)),
-                ('created_at', models.DateTimeField(auto_now_add=True)),
-                ('ebook', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='pace_notifications', to='books.ebook')),
-                ('meeting', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='pace_notifications', to='groups.groupmeeting')),
-                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='pace_notifications', to=settings.AUTH_USER_MODEL)),
-            ],
-            options={
-                'verbose_name': 'Pace Notification',
-                'verbose_name_plural': 'Pace Notifications',
-                'db_table': 'groups_pace_notification',
-                'ordering': ['-created_at'],
-                'indexes': [models.Index(fields=['user', 'meeting', 'ebook'], name='groups_pace_user_id_18e929_idx')],
-            },
-        ),
         migrations.CreateModel(
             name='GroupMembership',
             fields=[
                 ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
-                ('role', models.CharField(choices=[('admin', 'Admin'), ('member', 'Member')], default='member', max_length=16)),
+                ('role', models.CharField(choices=[('member', 'Member'), ('admin', 'Admin')], default='member', max_length=16)),
                 ('joined_at', models.DateTimeField(auto_now_add=True)),
                 ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='group_memberships', to=settings.AUTH_USER_MODEL)),
                 ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='memberships', to='groups.readinggroup')),
@@ -102,8 +46,30 @@ class Migration(migrations.Migration):
                 'verbose_name': 'Group Membership',
                 'verbose_name_plural': 'Group Memberships',
                 'db_table': 'groups_membership',
-                'indexes': [models.Index(fields=['user', 'group'], name='groups_memb_user_id_9cda7e_idx')],
+                'ordering': ['joined_at'],
-                'unique_together': {('user', 'group')},
+                'unique_together': {('group', 'user')},
+            },
+        ),
+        migrations.CreateModel(
+            name='MemberProgress',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('current_section', models.PositiveIntegerField(default=0)),
+                ('percentage', models.FloatField(default=0.0)),
+                ('time_spent_seconds', models.PositiveIntegerField(default=0)),
+                ('last_position', models.JSONField(blank=True, default=dict)),
+                ('is_public', models.BooleanField(default=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('membership', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='progress', to='groups.groupmembership')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='member_progress', to=settings.AUTH_USER_MODEL)),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='member_progress', to='groups.readinggroup')),
+            ],
+            options={
+                'verbose_name': 'Member Progress',
+                'verbose_name_plural': 'Member Progress',
+                'db_table': 'groups_member_progress',
+                'indexes': [models.Index(fields=['group', '-percentage'], name='groups_memb_group_i_42e333_idx'), models.Index(fields=['group', 'user'], name='groups_memb_group_i_f50793_idx')],
+                'unique_together': {('group', 'user')},
             },
         ),
     ]

backend/apps/groups/models.py

@@ -1,42 +1,14 @@
-from __future__ import annotations
-
 from django.conf import settings
 from django.db import models
 
 
-class FrequencyChoice(models.TextChoices):
-    DAILY = "daily", "Daily"
-    WEEKLY = "weekly", "Weekly"
-
-
-class MembershipRole(models.TextChoices):
-    ADMIN = "admin", "Admin"
-    MEMBER = "member", "Member"
-
-
-class NotificationStatus(models.TextChoices):
-    PENDING = "pending", "Pending"
-    SENT = "sent", "Sent"
-    DISMISSED = "dismissed", "Dismissed"
-
-
 class ReadingGroup(models.Model):
-    """A group of users reading a book together with scheduled meetings."""
+    """A group of users reading the same book together."""
 
     name = models.CharField(max_length=256, db_index=True)
-    description = models.TextField(blank=True, default="")
-    book = models.ForeignKey(
-        "books.Book",
-        on_delete=models.SET_NULL,
-        null=True,
-        blank=True,
-        related_name="reading_groups",
-    )
     ebook = models.ForeignKey(
         "books.EBook",
-        on_delete=models.SET_NULL,
+        on_delete=models.CASCADE,
-        null=True,
-        blank=True,
         related_name="reading_groups",
     )
     created_by = models.ForeignKey(
@@ -44,7 +16,9 @@ class ReadingGroup(models.Model):
         on_delete=models.CASCADE,
         related_name="created_groups",
     )
+    description = models.TextField(blank=True, default="")
     created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
 
     class Meta:
         db_table = "groups_reading_group"
@@ -55,24 +29,30 @@ class ReadingGroup(models.Model):
     def __str__(self) -> str:
         return self.name
 
+    @property
+    def total_sections(self) -> int:
+        return self.ebook.chapters.count()
+
 
 class GroupMembership(models.Model):
-    """User membership in a reading group."""
+    class Role(models.TextChoices):
+        MEMBER = "member", "Member"
+        ADMIN = "admin", "Admin"
 
-    user = models.ForeignKey(
-        settings.AUTH_USER_MODEL,
-        on_delete=models.CASCADE,
-        related_name="group_memberships",
-    )
     group = models.ForeignKey(
         ReadingGroup,
         on_delete=models.CASCADE,
         related_name="memberships",
     )
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="group_memberships",
+    )
     role = models.CharField(
         max_length=16,
-        choices=MembershipRole.choices,
+        choices=Role.choices,
-        default=MembershipRole.MEMBER,
+        default=Role.MEMBER,
     )
     joined_at = models.DateTimeField(auto_now_add=True)
 
@@ -80,111 +60,79 @@ class GroupMembership(models.Model):
         db_table = "groups_membership"
         verbose_name = "Group Membership"
         verbose_name_plural = "Group Memberships"
-        unique_together = [("user", "group")]
+        unique_together = [("group", "user")]
-        indexes = [models.Index(fields=["user", "group"])]
+        ordering = ["joined_at"]
 
     def __str__(self) -> str:
-        return f"{self.user} in {self.group}"
+        return f"{self.user} in {self.group.name} ({self.role})"
 
 
-class GroupMeeting(models.Model):
+class MemberProgress(models.Model):
-    """A scheduled meeting for a reading group with a target section."""
+    """Per-member reading progress within a reading group."""
 
+    membership = models.OneToOneField(
+        GroupMembership,
+        on_delete=models.CASCADE,
+        related_name="progress",
+    )
     group = models.ForeignKey(
         ReadingGroup,
         on_delete=models.CASCADE,
-        related_name="meetings",
+        related_name="member_progress",
     )
-    title = models.CharField(max_length=512, blank=True, default="")
-    scheduled_at = models.DateTimeField(db_index=True)
-    target_section = models.PositiveIntegerField(
-        default=0,
-        help_text="Target chapter/section index to reach by this meeting",
-    )
-    target_section_label = models.CharField(
-        max_length=512,
-        blank=True,
-        default="",
-        help_text="Human-readable label for the target section (e.g. 'Section 3')",
-    )
-    created_at = models.DateTimeField(auto_now_add=True)
-
-    class Meta:
-        db_table = "groups_meeting"
-        verbose_name = "Group Meeting"
-        verbose_name_plural = "Group Meetings"
-        ordering = ["scheduled_at"]
-
-    def __str__(self) -> str:
-        return f"{self.group.name} — {self.title or self.target_section_label} ({self.scheduled_at.date()})"
-
-
-class NotificationPreference(models.Model):
-    """Per-user notification settings for reading pace alerts."""
-
-    user = models.OneToOneField(
-        settings.AUTH_USER_MODEL,
-        on_delete=models.CASCADE,
-        related_name="notification_preference",
-        primary_key=True,
-    )
-    pace_notifications_enabled = models.BooleanField(default=True)
-    reminder_enabled = models.BooleanField(default=True)
-    frequency = models.CharField(
-        max_length=16,
-        choices=FrequencyChoice.choices,
-        default=FrequencyChoice.DAILY,
-    )
-    created_at = models.DateTimeField(auto_now_add=True)
-    updated_at = models.DateTimeField(auto_now=True)
-
-    class Meta:
-        db_table = "groups_notification_preference"
-        verbose_name = "Notification Preference"
-        verbose_name_plural = "Notification Preferences"
-
-    def __str__(self) -> str:
-        return f"{self.user} — pace={'on' if self.pace_notifications_enabled else 'off'}, freq={self.frequency}"
-
-
-class PaceNotification(models.Model):
-    """Tracks reading pace notifications sent to users to avoid duplicates."""
-
     user = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         on_delete=models.CASCADE,
-        related_name="pace_notifications",
+        related_name="member_progress",
-    )
-    meeting = models.ForeignKey(
-        GroupMeeting,
-        on_delete=models.CASCADE,
-        related_name="pace_notifications",
-    )
-    ebook = models.ForeignKey(
-        "books.EBook",
-        on_delete=models.CASCADE,
-        related_name="pace_notifications",
-        null=True,
-        blank=True,
-    )
-    status = models.CharField(
-        max_length=16,
-        choices=NotificationStatus.choices,
-        default=NotificationStatus.PENDING,
     )
     current_section = models.PositiveIntegerField(default=0)
-    target_section = models.PositiveIntegerField(default=0)
+    percentage = models.FloatField(default=0.0)
-    ahead_behind_delta = models.IntegerField(default=0)
+    time_spent_seconds = models.PositiveIntegerField(default=0)
-    created_at = models.DateTimeField(auto_now_add=True)
+    last_position = models.JSONField(blank=True, default=dict)
+    is_public = models.BooleanField(default=True)
+    updated_at = models.DateTimeField(auto_now=True)
 
     class Meta:
-        db_table = "groups_pace_notification"
+        db_table = "groups_member_progress"
-        verbose_name = "Pace Notification"
+        verbose_name = "Member Progress"
-        verbose_name_plural = "Pace Notifications"
+        verbose_name_plural = "Member Progress"
-        ordering = ["-created_at"]
+        unique_together = [("group", "user")]
         indexes = [
-            models.Index(fields=["user", "meeting", "ebook"]),
+            models.Index(fields=["group", "-percentage"]),
+            models.Index(fields=["group", "user"]),
         ]
 
     def __str__(self) -> str:
-        return f"{self.user} — meeting {self.meeting_id}: {self.get_status_display()}"
+        return f"{self.user} — {self.group.name} ({self.percentage:.0f}%)"
+
+    def total_sections(self) -> int:
+        return self.group.total_sections
+
+    def update_progress(
+        self,
+        current_section: int,
+        percentage: float | None = None,
+        time_spent_delta: int = 0,
+        last_position: dict | None = None,
+    ) -> None:
+        """Update progress with computed percentage if not provided."""
+        self.current_section = current_section
+        if percentage is not None:
+            self.percentage = min(100.0, max(0.0, percentage))
+        elif (ts := self.total_sections()) > 0:
+            self.percentage = min(100.0, (current_section / ts) * 100.0)
+        else:
+            self.percentage = 0.0
+        if time_spent_delta > 0:
+            self.time_spent_seconds += time_spent_delta
+        if last_position is not None:
+            self.last_position = last_position
+        self.save(
+            update_fields=[
+                "current_section",
+                "percentage",
+                "time_spent_seconds",
+                "last_position",
+                "updated_at",
+            ]
+        )

backend/apps/groups/permissions.py

@@ -0,0 +1,28 @@
+from rest_framework import permissions
+from rest_framework.request import Request
+
+from apps.groups.models import GroupMembership
+
+
+class IsGroupMember(permissions.BasePermission):
+    """Allow access only to members of the group."""
+
+    def has_permission(self, request: Request, view: object) -> bool:
+        group_id = view.kwargs.get("group_pk") or view.kwargs.get("pk")
+        if not group_id:
+            return False
+        return GroupMembership.objects.filter(
+            group_id=group_id, user=request.user
+        ).exists()
+
+
+class IsGroupAdmin(permissions.BasePermission):
+    """Allow access only to group admins."""
+
+    def has_permission(self, request: Request, view: object) -> bool:
+        group_id = view.kwargs.get("group_pk") or view.kwargs.get("pk")
+        if not group_id:
+            return False
+        return GroupMembership.objects.filter(
+            group_id=group_id, user=request.user, role=GroupMembership.Role.ADMIN
+        ).exists()

backend/apps/groups/serializers.py

@@ -1,137 +1,183 @@
-from __future__ import annotations
-
 from rest_framework import serializers
 
-from apps.groups.models import (
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
-    FrequencyChoice,
-    GroupMeeting,
-    GroupMembership,
-    NotificationPreference,
-    PaceNotification,
-    ReadingGroup,
-)
-from apps.groups.services.pace import PaceStatus
 
 
-class NotificationPreferenceSerializer(serializers.ModelSerializer):
+class GroupMembershipSerializer(serializers.ModelSerializer):
-    class Meta:
+    user_email = serializers.CharField(source="user.email", read_only=True)
-        model = NotificationPreference
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
-        fields = [
+    role = serializers.CharField(read_only=True)
-            "pace_notifications_enabled",
-            "reminder_enabled",
-            "frequency",
-        ]
-
-    def validate_frequency(self, value: str) -> str:
-        valid = {choice[0] for choice in FrequencyChoice.choices}
-        if value not in valid:
-            raise serializers.ValidationError(
-                f"Frequency must be one of: {', '.join(valid)}"
-            )
-        return value
-
-
-class GroupMeetingSerializer(serializers.ModelSerializer):
-    group_name = serializers.CharField(source="group.name", read_only=True)
 
     class Meta:
-        model = GroupMeeting
+        model = GroupMembership
+        fields = ["id", "user_id", "user_email", "role", "joined_at"]
+
+
+class MemberProgressSerializer(serializers.ModelSerializer):
+    user_email = serializers.CharField(source="user.email", read_only=True)
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
+    total_sections = serializers.SerializerMethodField()
+    section_label = serializers.SerializerMethodField()
+
+    class Meta:
+        model = MemberProgress
         fields = [
             "id",
-            "group",
+            "user_id",
-            "group_name",
+            "user_email",
-            "title",
+            "current_section",
-            "scheduled_at",
+            "total_sections",
-            "target_section",
+            "section_label",
-            "target_section_label",
+            "percentage",
-            "created_at",
+            "time_spent_seconds",
+            "last_position",
+            "is_public",
+            "updated_at",
         ]
-        read_only_fields = ["id", "created_at"]
+        read_only_fields = ["id", "user_id", "user_email", "updated_at"]
+        extra_kwargs = {
+            "percentage": {"required": False, "min_value": 0.0, "max_value": 100.0},
+        }
 
-    def validate_target_section(self, value: int) -> int:
+    def get_total_sections(self, obj: MemberProgress) -> int:
-        if value < 0:
+        return obj.total_sections()
-            raise serializers.ValidationError("Target section must be non-negative.")
+
+    def get_section_label(self, obj: MemberProgress) -> str:
+        ts = obj.total_sections()
+        if ts:
+            return f"Section {obj.current_section} of {ts}"
+        return "No sections"
+
+    def validate_percentage(self, value: float) -> float:
+        if value < 0.0 or value > 100.0:
+            raise serializers.ValidationError("Percentage must be between 0.0 and 100.0.")
         return value
 
 
-class ReadingGroupSerializer(serializers.ModelSerializer):
+class MemberProgressPublicSerializer(serializers.ModelSerializer):
+    """Limited view for other group members — section label only, no exact position."""
+
+    user_email = serializers.CharField(source="user.email", read_only=True)
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
+    total_sections = serializers.SerializerMethodField()
+    section_label = serializers.SerializerMethodField()
+
+    class Meta:
+        model = MemberProgress
+        fields = [
+            "user_id",
+            "user_email",
+            "current_section",
+            "total_sections",
+            "section_label",
+            "percentage",
+            "time_spent_seconds",
+            "updated_at",
+        ]
+
+    def get_total_sections(self, obj: MemberProgress) -> int:
+        return obj.total_sections()
+
+    def get_section_label(self, obj: MemberProgress) -> str:
+        ts = obj.total_sections()
+        if ts:
+            return f"Section {obj.current_section} of {ts}"
+        return "No sections"
+
+
+class MemberProgressUpdateSerializer(serializers.Serializer):
+    current_section = serializers.IntegerField(min_value=0)
+    percentage = serializers.FloatField(required=False, min_value=0.0, max_value=100.0)
+    time_spent_delta = serializers.IntegerField(default=0, min_value=0)
+    last_position = serializers.JSONField(required=False, default=dict)
+    is_public = serializers.BooleanField(required=False)
+
+
+class ReadingGroupListSerializer(serializers.ModelSerializer):
+    created_by_email = serializers.CharField(source="created_by.email", read_only=True)
+    ebook_title = serializers.CharField(source="ebook.title", read_only=True)
+    ebook_author = serializers.CharField(source="ebook.author", read_only=True)
     member_count = serializers.SerializerMethodField()
-    meeting_count = serializers.SerializerMethodField()
+    my_progress = serializers.SerializerMethodField()
 
     class Meta:
         model = ReadingGroup
         fields = [
             "id",
             "name",
-            "description",
-            "book",
             "ebook",
-            "created_by",
+            "ebook_title",
-            "created_at",
+            "ebook_author",
+            "created_by_email",
+            "description",
             "member_count",
-            "meeting_count",
+            "my_progress",
+            "created_at",
+            "updated_at",
         ]
-        read_only_fields = ["id", "created_by", "created_at"]
 
     def get_member_count(self, obj: ReadingGroup) -> int:
         return obj.memberships.count()
 
-    def get_meeting_count(self, obj: ReadingGroup) -> int:
+    def get_my_progress(self, obj: ReadingGroup) -> dict | None:
-        return obj.meetings.count()
+        request = self.context.get("request")
+        if not request or not request.user.is_authenticated:
+            return None
+        try:
+            mp = MemberProgress.objects.get(group=obj, user=request.user)
+        except MemberProgress.DoesNotExist:
+            return None
+        return {
+            "current_section": mp.current_section,
+            "percentage": mp.percentage,
+            "time_spent_seconds": mp.time_spent_seconds,
+            "section_label": MemberProgressSerializer().get_section_label(mp),
+        }
 
 
-class GroupMembershipSerializer(serializers.ModelSerializer):
+class ReadingGroupDetailSerializer(ReadingGroupListSerializer):
-    user_email = serializers.CharField(source="user.email", read_only=True)
+    members = serializers.SerializerMethodField()
-    group_name = serializers.CharField(source="group.name", read_only=True)
 
+    class Meta(ReadingGroupListSerializer.Meta):
+        fields = ReadingGroupListSerializer.Meta.fields + ["members"]
+
+    def get_members(self, obj: ReadingGroup) -> list[dict]:
+        memberships = obj.memberships.select_related("user").prefetch_related("progress")
+        result: list[dict] = []
+        for m in memberships:
+            entry: dict = {
+                "id": m.id,
+                "user_id": m.user.id,
+                "user_email": m.user.email,
+                "role": m.role,
+                "joined_at": m.joined_at,
+            }
+            try:
+                mp = m.progress
+            except MemberProgress.DoesNotExist:
+                entry["progress"] = None
+            else:
+                if mp.is_public:
+                    entry["progress"] = MemberProgressPublicSerializer(mp).data
+                else:
+                    entry["progress"] = {"is_public": False, "note": "Private"}
+            result.append(entry)
+        return result
+
+
+class ReadingGroupCreateSerializer(serializers.ModelSerializer):
     class Meta:
-        model = GroupMembership
+        model = ReadingGroup
-        fields = ["id", "user", "user_email", "group", "group_name", "role", "joined_at"]
+        fields = ["name", "ebook", "description"]
-        read_only_fields = ["id", "joined_at"]
 
 
-class PaceNotificationSerializer(serializers.ModelSerializer):
+class AdminProgressSummarySerializer(serializers.Serializer):
-    status_display = serializers.CharField(source="get_status_display", read_only=True)
+    group_id = serializers.IntegerField()
-
-    class Meta:
-        model = PaceNotification
-        fields = [
-            "id",
-            "user",
-            "meeting",
-            "ebook",
-            "status",
-            "status_display",
-            "current_section",
-            "target_section",
-            "ahead_behind_delta",
-            "created_at",
-        ]
-        read_only_fields = ["id", "created_at"]
-
-
-class PaceStatusSerializer(serializers.Serializer):
-    meeting_id = serializers.IntegerField()
-    meeting_title = serializers.CharField()
-    scheduled_at = serializers.CharField()
-    target_section = serializers.IntegerField()
-    target_section_label = serializers.CharField()
-    current_section = serializers.IntegerField()
-    ahead_behind_delta = serializers.IntegerField()
-    status = serializers.CharField()
-    days_until_meeting = serializers.IntegerField()
-    sections_to_catch_up = serializers.IntegerField()
-    ebook_id = serializers.IntegerField()
-    ebook_title = serializers.CharField()
-
-
-class ReminderSerializer(serializers.Serializer):
-    meeting_id = serializers.IntegerField()
-    meeting_title = serializers.CharField()
-    scheduled_at = serializers.CharField()
-    target_section = serializers.IntegerField()
-    target_section_label = serializers.CharField()
     group_name = serializers.CharField()
-    hours_until = serializers.IntegerField()
-    ebook_id = serializers.IntegerField()
     ebook_title = serializers.CharField()
+    total_members = serializers.IntegerField()
+    members_started = serializers.IntegerField()
+    members_finished = serializers.IntegerField()
+    average_percentage = serializers.FloatField()
+    average_time_spent_hours = serializers.FloatField()
+    member_details = serializers.ListField(child=serializers.JSONField())

backend/apps/groups/services/pace.py

@@ -1,219 +0,0 @@
-"""Pace calculation service for reading progress vs meeting targets."""
-
-from __future__ import annotations
-
-import logging
-from datetime import datetime, timedelta
-from typing import TypedDict
-
-from django.db.models import QuerySet
-from django.utils import timezone
-
-from apps.books.models import EBook, ReadingProgress
-from apps.groups.models import (
-    GroupMeeting,
-    GroupMembership,
-    NotificationPreference,
-    PaceNotification,
-    NotificationStatus,
-)
-
-logger = logging.getLogger(__name__)
-
-
-class PaceStatus(TypedDict):
-    meeting_id: int
-    meeting_title: str
-    scheduled_at: str
-    target_section: int
-    target_section_label: str
-    current_section: int
-    ahead_behind_delta: int
-    status: str  # "ahead", "behind", "on_track", "completed"
-    days_until_meeting: int
-    sections_to_catch_up: int
-    ebook_id: int
-    ebook_title: str
-
-
-def get_relevant_ebooks_for_user(user) -> QuerySet[EBook]:
-    """Return ebooks that belong to groups the user is a member of."""
-    group_ids = (
-        GroupMembership.objects.filter(user=user)
-        .values_list("group_id", flat=True)
-    )
-    return (
-        EBook.objects.filter(reading_groups__in=group_ids)
-        .select_related("reading_progress")
-        .prefetch_related("chapters")
-        .distinct()
-    )
-
-
-def calculate_pace(
-    user,
-    ebook: EBook | None = None,
-    meeting: GroupMeeting | None = None,
-) -> list[PaceStatus]:
-    """Calculate reading pace for a user's upcoming meetings.
-
-    Compares the user's current reading progress (chapter index) against
-    the target section for each upcoming meeting within 3 days.
-    """
-    now = timezone.now()
-    three_days_from_now = now + timedelta(days=3)
-
-    # Find upcoming meetings for groups the user belongs to
-    user_group_ids = (
-        GroupMembership.objects.filter(user=user)
-        .values_list("group_id", flat=True)
-    )
-    meetings_qs = GroupMeeting.objects.filter(
-        group_id__in=user_group_ids,
-        scheduled_at__gte=now,
-        scheduled_at__lte=three_days_from_now,
-    ).select_related("group", "group__ebook")
-
-    if meeting:
-        meetings_qs = meetings_qs.filter(pk=meeting.pk)
-
-    meetings = list(meetings_qs)
-
-    results: list[PaceStatus] = []
-
-    for m in meetings:
-        group_ebook = m.group.ebook
-        ebooks_to_check: list[EBook] = []
-
-        if ebook:
-            ebooks_to_check = [ebook]
-        elif group_ebook:
-            ebooks_to_check = [group_ebook]
-        else:
-            # Check all ebooks in the group
-            ebooks_to_check = list(
-                EBook.objects.filter(reading_groups=m.group)
-                .select_related("reading_progress")
-                .prefetch_related("chapters")
-            )
-
-        for eb in ebooks_to_check:
-            pace = _compute_single_pace(user, m, eb, now)
-            if pace:
-                results.append(pace)
-
-    return results
-
-
-def _compute_single_pace(
-    user,
-    meeting: GroupMeeting,
-    ebook: EBook,
-    now: datetime,
-) -> PaceStatus | None:
-    """Compute pace for one user + meeting + ebook combination."""
-    try:
-        progress = ebook.reading_progress
-    except ReadingProgress.DoesNotExist:
-        # No progress yet — user hasn't started reading
-        return None
-
-    # Current section: based on last_page (chapter index) or computed from progress %
-    if progress.last_page > 0:
-        current_section = progress.last_page
-    elif progress.current_position > 0:
-        chapter_count = ebook.chapters.count() or ebook.page_count or 1
-        current_section = max(1, int((progress.current_position / 100) * chapter_count))
-    else:
-        current_section = 0
-
-    target_section = meeting.target_section or 0
-    if target_section == 0:
-        return None
-
-    delta = current_section - target_section
-    days_until = max(0, (meeting.scheduled_at - now).days)
-
-    if current_section >= target_section:
-        if current_section >= target_section and progress.current_position > 0:
-            status = "completed"
-        else:
-            status = "ahead"
-    elif delta >= -1:
-        status = "on_track"
-    else:
-        status = "behind"
-
-    return PaceStatus(
-        meeting_id=meeting.pk,
-        meeting_title=meeting.title or meeting.target_section_label,
-        scheduled_at=meeting.scheduled_at.isoformat(),
-        target_section=target_section,
-        target_section_label=meeting.target_section_label,
-        current_section=current_section,
-        ahead_behind_delta=delta,
-        status=status,
-        days_until_meeting=days_until,
-        sections_to_catch_up=max(0, target_section - current_section),
-        ebook_id=ebook.pk,
-        ebook_title=ebook.title,
-    )
-
-
-def should_send_notification(
-    user,
-    meeting: GroupMeeting,
-    ebook: EBook,
-) -> bool:
-    """Check if a pace notification should be sent based on user preferences."""
-    pref, _ = NotificationPreference.objects.get_or_create(user=user)
-
-    if not pref.pace_notifications_enabled:
-        return False
-
-    # Check if notification was already sent today
-    today = timezone.now().date()
-    existing = PaceNotification.objects.filter(
-        user=user,
-        meeting=meeting,
-        ebook=ebook,
-        created_at__date=today,
-    ).exclude(status=NotificationStatus.DISMISSED)
-
-    if existing.exists():
-        return False
-
-    # Frequency check
-    if pref.frequency == "weekly":
-        week_ago = today - timedelta(days=7)
-        recent = PaceNotification.objects.filter(
-            user=user,
-            meeting=meeting,
-            ebook=ebook,
-            created_at__date__gte=week_ago,
-        ).exclude(status=NotificationStatus.DISMISSED)
-        if recent.exists():
-            return False
-
-    return True
-
-
-def get_reminder_meetings(user) -> list[GroupMeeting]:
-    """Get meetings that are within 24 hours for reminder notifications."""
-    now = timezone.now()
-    tomorrow = now + timedelta(days=1)
-
-    user_group_ids = (
-        GroupMembership.objects.filter(user=user)
-        .values_list("group_id", flat=True)
-    )
-
-    return list(
-        GroupMeeting.objects.filter(
-            group_id__in=user_group_ids,
-            scheduled_at__gte=now,
-            scheduled_at__lte=tomorrow,
-        )
-        .select_related("group", "group__ebook")
-        .order_by("scheduled_at")
-    )

backend/apps/groups/urls.py

@@ -1,23 +1,11 @@
 from django.urls import include, path
 from rest_framework.routers import DefaultRouter
 
-from apps.groups.views import (
+from apps.groups.views import ReadingGroupViewSet
-    GroupMeetingViewSet,
-    ReadingGroupViewSet,
-    dismiss_pace_notification_view,
-    notification_preferences_view,
-    pace_status_view,
-    reminder_view,
-)
 
 router = DefaultRouter()
-router.register(r"groups", ReadingGroupViewSet, basename="reading-group")
+router.register(r"", ReadingGroupViewSet, basename="reading-group")
-router.register(r"meetings", GroupMeetingViewSet, basename="group-meeting")
 
 urlpatterns = [
     path("", include(router.urls)),
-    path("notifications/preferences/", notification_preferences_view, name="notification-preferences"),
-    path("notifications/pace/", pace_status_view, name="pace-status"),
-    path("notifications/dismiss/", dismiss_pace_notification_view, name="dismiss-pace"),
-    path("notifications/reminders/", reminder_view, name="meeting-reminders"),
 ]

backend/apps/groups/views.py

@@ -1,207 +1,203 @@
 from __future__ import annotations
 
-from django.db.models import QuerySet
+from django.db import models
 from rest_framework import permissions, status, viewsets
-from rest_framework.decorators import action, api_view, permission_classes
+from rest_framework.decorators import action
-from rest_framework.permissions import IsAuthenticated
 from rest_framework.request import Request
 from rest_framework.response import Response
 
-from apps.books.models import EBook
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
-from apps.groups.models import (
+from apps.groups.permissions import IsGroupAdmin, IsGroupMember
-    GroupMeeting,
-    GroupMembership,
-    NotificationPreference,
-    PaceNotification,
-    NotificationStatus,
-    ReadingGroup,
-)
 from apps.groups.serializers import (
-    GroupMeetingSerializer,
+    AdminProgressSummarySerializer,
     GroupMembershipSerializer,
-    NotificationPreferenceSerializer,
+    MemberProgressPublicSerializer,
-    PaceNotificationSerializer,
+    MemberProgressSerializer,
-    PaceStatusSerializer,
+    MemberProgressUpdateSerializer,
-    ReadingGroupSerializer,
+    ReadingGroupCreateSerializer,
-    ReminderSerializer,
+    ReadingGroupDetailSerializer,
-)
+    ReadingGroupListSerializer,
-from apps.groups.services.pace import (
-    calculate_pace,
-    get_reminder_meetings,
-    should_send_notification,
 )
 
+import logging
 
-class IsGroupMember(permissions.BasePermission):
+logger = logging.getLogger(__name__)
-    """Only allow group members to access group resources."""
-
-    def has_object_permission(self, request: Request, view: object, obj: ReadingGroup) -> bool:
-        return obj.memberships.filter(user=request.user).exists()
 
 
 class ReadingGroupViewSet(viewsets.ModelViewSet):
-    permission_classes = [IsAuthenticated, IsGroupMember]
+    permission_classes = [permissions.IsAuthenticated]
-    serializer_class = ReadingGroupSerializer
 
-    def get_queryset(self) -> QuerySet[ReadingGroup]:
+    def get_queryset(self):
         return (
             ReadingGroup.objects.filter(memberships__user=self.request.user)
-            .prefetch_related("memberships", "meetings")
+            .select_related("ebook", "created_by")
+            .prefetch_related("memberships", "memberships__progress")
             .distinct()
         )
 
-    def perform_create(self, serializer) -> None:
+    def get_serializer_class(self):
+        if self.action == "create":
+            return ReadingGroupCreateSerializer
+        if self.action == "retrieve":
+            return ReadingGroupDetailSerializer
+        return ReadingGroupListSerializer
+
+    def perform_create(self, serializer):
         group = serializer.save(created_by=self.request.user)
+        # Creator automatically becomes admin member
         GroupMembership.objects.create(
-            user=self.request.user,
             group=group,
-            role="admin",
+            user=self.request.user,
+            role=GroupMembership.Role.ADMIN,
         )
 
-    @action(detail=False, methods=["get"], url_path="all")
+    # ── Membership ───────────────────────────────────────────────────────
-    def all_groups(self, request: Request) -> Response:
-        """Return all groups (for discovery)."""
-        qs = ReadingGroup.objects.all().prefetch_related("memberships", "meetings")
-        page = self.paginate_queryset(qs)
-        if page is not None:
-            serializer = self.get_serializer(page, many=True)
-            return self.get_paginated_response(serializer.data)
-        serializer = self.get_serializer(qs, many=True)
-        return Response(serializer.data)
 
-
+    @action(detail=True, methods=["post"], permission_classes=[IsGroupMember])
-class GroupMeetingViewSet(viewsets.ModelViewSet):
+    def join(self, request: Request, pk: int | None = None) -> Response:
-    permission_classes = [IsAuthenticated]
+        """Join a reading group (public join link)."""
-    serializer_class = GroupMeetingSerializer
+        group = self.get_object()
-
+        membership, created = GroupMembership.objects.get_or_create(
-    def get_queryset(self) -> QuerySet[GroupMeeting]:
+            group=group, user=request.user
-        user_group_ids = (
-            GroupMembership.objects.filter(user=self.request.user)
-            .values_list("group_id", flat=True)
         )
-        return GroupMeeting.objects.filter(group_id__in=user_group_ids).select_related(
+        if not created:
-            "group"
+            return Response({"detail": "Already a member."}, status=status.HTTP_200_OK)
+        MemberProgress.objects.get_or_create(
+            membership=membership,
+            group=group,
+            user=request.user,
+            defaults={"current_section": 0, "percentage": 0.0},
         )
+        return Response({"detail": "Joined successfully."}, status=status.HTTP_201_CREATED)
 
-    def perform_create(self, serializer) -> None:
+    @action(detail=True, methods=["post"], permission_classes=[IsGroupMember])
-        group = serializer.validated_data["group"]
+    def leave(self, request: Request, pk: int | None = None) -> Response:
-        if not group.memberships.filter(user=self.request.user).exists():
+        """Leave a reading group."""
-            raise permissions.PermissionDenied("You must be a group member to create meetings.")
+        group = self.get_object()
-        serializer.save()
+        if group.created_by == request.user:
-
-    @action(detail=False, methods=["get"], url_path="upcoming")
-    def upcoming(self, request: Request) -> Response:
-        """Return upcoming meetings for the user's groups (within 3 days)."""
-        from django.utils import timezone
-        from datetime import timedelta
-
-        now = timezone.now()
-        three_days = now + timedelta(days=3)
-        qs = self.get_queryset().filter(
-            scheduled_at__gte=now,
-            scheduled_at__lte=three_days,
-        )
-        serializer = self.get_serializer(qs, many=True)
-        return Response(serializer.data)
-
-
-@api_view(["GET", "PATCH"])
-@permission_classes([IsAuthenticated])
-def notification_preferences_view(request: Request) -> Response:
-    """Get or update notification preferences for the current user."""
-    pref, _created = NotificationPreference.objects.get_or_create(user=request.user)
-
-    if request.method == "GET":
-        serializer = NotificationPreferenceSerializer(pref)
-        return Response(serializer.data)
-
-    serializer = NotificationPreferenceSerializer(pref, data=request.data, partial=True)
-    serializer.is_valid(raise_exception=True)
-    serializer.save()
-    return Response(serializer.data)
-
-
-@api_view(["GET"])
-@permission_classes([IsAuthenticated])
-def pace_status_view(request: Request) -> Response:
-    """Get reading pace status for the current user's upcoming meetings."""
-    ebook_id = request.query_params.get("ebook_id")
-    ebook: EBook | None = None
-
-    if ebook_id:
-        try:
-            ebook = EBook.objects.select_related("reading_progress").prefetch_related("chapters").get(
-                pk=ebook_id, user=request.user
-            )
-        except EBook.DoesNotExist:
             return Response(
-                {"error": "EBook not found."}, status=status.HTTP_404_NOT_FOUND
+                {"error": "Group creator cannot leave. Transfer ownership or delete the group."},
-            )
-
-    pace_data = calculate_pace(request.user, ebook=ebook)
-    serializer = PaceStatusSerializer(pace_data, many=True)
-    return Response(serializer.data)
-
-
-@api_view(["POST"])
-@permission_classes([IsAuthenticated])
-def dismiss_pace_notification_view(request: Request) -> Response:
-    """Dismiss a pace notification so it won't show again."""
-    meeting_id = request.data.get("meeting_id")
-    ebook_id = request.data.get("ebook_id")
-
-    if not meeting_id or not ebook_id:
-        return Response(
-            {"error": "meeting_id and ebook_id are required."},
                 status=status.HTTP_400_BAD_REQUEST,
             )
+        GroupMembership.objects.filter(group=group, user=request.user).delete()
+        return Response(status=status.HTTP_204_NO_CONTENT)
 
-    PaceNotification.objects.filter(
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupMember])
-        user=request.user,
+    def members(self, request: Request, pk: int | None = None) -> Response:
-        meeting_id=meeting_id,
+        """List group members with their progress."""
-        ebook_id=ebook_id,
+        group = self.get_object()
-        status=NotificationStatus.PENDING,
+        memberships = (
-    ).update(status=NotificationStatus.DISMISSED)
+            group.memberships.select_related("user")
-
+            .prefetch_related("progress")
-    return Response({"status": "dismissed"})
+            .all()
-
-
-@api_view(["GET"])
-@permission_classes([IsAuthenticated])
-def reminder_view(request: Request) -> Response:
-    """Get pre-meeting reminders for meetings within 24 hours."""
-    pref, _ = NotificationPreference.objects.get_or_create(user=request.user)
-    if not pref.reminder_enabled:
-        return Response([])
-
-    meetings = get_reminder_meetings(request.user)
-    now_dt = __import__("django").utils.timezone.now()
-
-    reminders = []
-    for mtg in meetings:
-        group_ebook = mtg.group.ebook
-        ebook: EBook | None = group_ebook
-        if not ebook:
-            ebooks = list(
-                EBook.objects.filter(reading_groups=mtg.group).select_related("reading_progress")[:1]
         )
-            ebook = ebooks[0] if ebooks else None
+        serializer = GroupMembershipSerializer(memberships, many=True)
+        return Response(serializer.data)
 
-        if not ebook:
+    # ── Progress ─────────────────────────────────────────────────────────
-            continue
 
-        hours_until = max(0, int((mtg.scheduled_at - now_dt).total_seconds() / 3600))
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupMember],
-        reminders.append({
+            url_path="members/progress")
-            "meeting_id": mtg.pk,
+    def members_progress(self, request: Request, pk: int | None = None) -> Response:
-            "meeting_title": mtg.title or mtg.target_section_label,
+        """Get progress for all group members.
-            "scheduled_at": mtg.scheduled_at.isoformat(),
+
-            "target_section": mtg.target_section,
+        Other members' progress shows section label only (no last_position).
-            "target_section_label": mtg.target_section_label,
+        Your own progress shows full detail.
-            "group_name": mtg.group.name,
+        """
-            "hours_until": hours_until,
+        group = self.get_object()
-            "ebook_id": ebook.pk,
+        progress_qs = (
-            "ebook_title": ebook.title,
+            MemberProgress.objects.filter(group=group)
+            .select_related("user")
+            .order_by("-percentage")
+        )
+        result: list[dict] = []
+        for mp in progress_qs:
+            if mp.user == request.user:
+                result.append(MemberProgressSerializer(mp).data)
+            elif mp.is_public:
+                result.append(MemberProgressPublicSerializer(mp).data)
+            else:
+                result.append({
+                    "user_id": mp.user.id,
+                    "user_email": mp.user.email,
+                    "is_public": False,
+                    "note": "Private",
+                })
+        return Response(result)
+
+    @action(detail=True, methods=["get", "patch"], permission_classes=[IsGroupMember],
+            url_path="progress")
+    def my_progress(self, request: Request, pk: int | None = None) -> Response:
+        """Get or update my own progress in the group."""
+        group = self.get_object()
+        membership = GroupMembership.objects.get(group=group, user=request.user)
+        progress_obj, _created = MemberProgress.objects.get_or_create(
+            membership=membership,
+            group=group,
+            user=request.user,
+        )
+
+        if request.method == "GET":
+            serializer = MemberProgressSerializer(progress_obj)
+            return Response(serializer.data)
+
+        # PATCH — update progress
+        update_serializer = MemberProgressUpdateSerializer(data=request.data)
+        update_serializer.is_valid(raise_exception=True)
+        data = update_serializer.validated_data
+
+        progress_obj.update_progress(
+            current_section=data["current_section"],
+            percentage=data.get("percentage"),
+            time_spent_delta=data.get("time_spent_delta", 0),
+            last_position=data.get("last_position"),
+        )
+        if "is_public" in data:
+            progress_obj.is_public = data["is_public"]
+            progress_obj.save(update_fields=["is_public"])
+
+        serializer = MemberProgressSerializer(progress_obj)
+        return Response(serializer.data)
+
+    # ── Admin ────────────────────────────────────────────────────────────
+
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupAdmin],
+            url_path="progress/summary")
+    def progress_summary(self, request: Request, pk: int | None = None) -> Response:
+        """Admin summary of all member progress."""
+        group = self.get_object()
+        progress_qs = MemberProgress.objects.filter(group=group).select_related("user")
+
+        total_members = group.memberships.count()
+        members_started = progress_qs.filter(current_section__gt=0).count()
+        members_finished = progress_qs.filter(percentage__gte=100.0).count()
+
+        avg_pct = progress_qs.aggregate(avg=models.Avg("percentage"))["avg"] or 0.0
+        avg_time = progress_qs.aggregate(avg=models.Avg("time_spent_seconds"))["avg"] or 0.0
+
+        member_details: list[dict] = []
+        for mp in progress_qs:
+            member_details.append({
+                "user_id": mp.user.id,
+                "user_email": mp.user.email,
+                "current_section": mp.current_section,
+                "percentage": mp.percentage,
+                "time_spent_seconds": mp.time_spent_seconds,
+                "is_public": mp.is_public,
+                "updated_at": mp.updated_at,
             })
 
-    serializer = ReminderSerializer(reminders, many=True)
+        summary_data = {
+            "group_id": group.id,
+            "group_name": group.name,
+            "ebook_title": group.ebook.title,
+            "total_members": total_members,
+            "members_started": members_started,
+            "members_finished": members_finished,
+            "average_percentage": round(avg_pct, 1),
+            "average_time_spent_hours": round(avg_time / 3600.0, 1) if avg_time else 0.0,
+            "member_details": member_details,
+        }
+        serializer = AdminProgressSummarySerializer(data=summary_data)
+        serializer.is_valid(raise_exception=True)
         return Response(serializer.data)

frontend/src/App.tsx

@@ -12,6 +12,8 @@ const AddBookPage = lazy(() => import("./pages/AddBook").then((m) => ({ default:
 const SettingsPage = lazy(() => import("./pages/Settings").then((m) => ({ default: m.SettingsPage })));
 const BookmarksNotesPage = lazy(() => import("./components/annotations/BookmarksNotesPage").then((m) => ({ default: m.BookmarksNotesPage })));
 const ReadingPage = lazy(() => import("./pages/ReadingPage").then((m) => ({ default: m.default })));
+const ReadingGroupsPage = lazy(() => import("./pages/ReadingGroups").then((m) => ({ default: m.ReadingGroupsPage })));
+const GroupDetailPage = lazy(() => import("./pages/GroupDetail").then((m) => ({ default: m.GroupDetailPage })));
 
 const AuthPage = lazy(() => import("./pages/AuthPage"));
 
@@ -45,6 +47,8 @@ function AppRoutes() {
         <Route path="/add" element={<ProtectedRoute><AddBookPage /></ProtectedRoute>} />
         <Route path="/settings" element={<ProtectedRoute><SettingsPage /></ProtectedRoute>} />
         <Route path="/bookmarks-notes/:bookId?" element={<ProtectedRoute><BookmarksNotesPage /></ProtectedRoute>} />
+        <Route path="/groups" element={<ProtectedRoute><ReadingGroupsPage /></ProtectedRoute>} />
+        <Route path="/groups/:id" element={<ProtectedRoute><GroupDetailPage /></ProtectedRoute>} />
         <Route path="*" element={<Navigate to="/" replace />} />
       </Routes>
     </Suspense>

frontend/src/api/groups.ts

@@ -1,57 +1,81 @@
 import api from "./client";
 import type {
-  GroupMeeting,
+  AdminProgressSummary,
-  MeetingReminder,
+  CreateGroupPayload,
-  NotificationPreferences,
+  MemberProgressDetail,
-  PaceStatus,
+  MemberProgressEntry,
-  ReadingGroup,
+  ReadingGroupDetail,
-} from "../types/notifications";
+  ReadingGroupSummary,
+  UpdateProgressPayload,
+} from "../types/groups";
 
 export const groupsApi = {
-  async getPaceStatus(ebookId?: number): Promise<PaceStatus[]> {
+  /* ── Groups ── */
-    const params: Record<string, string> = {};
-    if (ebookId) params.ebook_id = String(ebookId);
-    const { data } = await api.get<PaceStatus[]>("/groups/notifications/pace/", { params });
-    return data;
-  },
 
-  async getPreferences(): Promise<NotificationPreferences> {
+  async listGroups(): Promise<ReadingGroupSummary[]> {
-    const { data } = await api.get<NotificationPreferences>("/groups/notifications/preferences/");
+    const { data } = await api.get<ReadingGroupSummary[]>("/groups/");
-    return data;
-  },
-
-  async updatePreferences(
-    prefs: Partial<NotificationPreferences>,
-  ): Promise<NotificationPreferences> {
-    const { data } = await api.patch<NotificationPreferences>(
-      "/groups/notifications/preferences/",
-      prefs,
-    );
-    return data;
-  },
-
-  async dismissPaceNotification(meetingId: number, ebookId: number): Promise<void> {
-    await api.post("/groups/notifications/dismiss/", {
-      meeting_id: meetingId,
-      ebook_id: ebookId,
-    });
-  },
-
-  async getReminders(): Promise<MeetingReminder[]> {
-    const { data } = await api.get<MeetingReminder[]>("/groups/notifications/reminders/");
-    return data;
-  },
-
-  async getGroups(): Promise<ReadingGroup[]> {
-    const { data } = await api.get<{ count: number; results: ReadingGroup[] } | ReadingGroup[]>(
-      "/groups/groups/",
-    );
     if (Array.isArray(data)) return data;
-    return data.results ?? [];
+    return (data as { results: ReadingGroupSummary[] }).results ?? [];
   },
 
-  async getUpcomingMeetings(): Promise<GroupMeeting[]> {
+  async getGroup(id: number): Promise<ReadingGroupDetail> {
-    const { data } = await api.get<GroupMeeting[]>("/groups/meetings/upcoming/");
+    const { data } = await api.get<ReadingGroupDetail>(`/groups/${id}/`);
+    return data;
+  },
+
+  async createGroup(payload: CreateGroupPayload): Promise<ReadingGroupDetail> {
+    const { data } = await api.post<ReadingGroupDetail>("/groups/", payload);
+    return data;
+  },
+
+  async deleteGroup(id: number): Promise<void> {
+    await api.delete(`/groups/${id}/`);
+  },
+
+  /* ── Membership ── */
+
+  async joinGroup(id: number): Promise<{ detail: string }> {
+    const { data } = await api.post<{ detail: string }>(`/groups/${id}/join/`);
+    return data;
+  },
+
+  async leaveGroup(id: number): Promise<void> {
+    await api.post(`/groups/${id}/leave/`);
+  },
+
+  /* ── Progress ── */
+
+  async getMembersProgress(groupId: number): Promise<MemberProgressEntry[]> {
+    const { data } = await api.get<MemberProgressEntry[]>(
+      `/groups/${groupId}/members/progress/`,
+    );
+    return data;
+  },
+
+  async getMyProgress(groupId: number): Promise<MemberProgressDetail> {
+    const { data } = await api.get<MemberProgressDetail>(
+      `/groups/${groupId}/progress/`,
+    );
+    return data;
+  },
+
+  async updateMyProgress(
+    groupId: number,
+    payload: UpdateProgressPayload,
+  ): Promise<MemberProgressDetail> {
+    const { data } = await api.patch<MemberProgressDetail>(
+      `/groups/${groupId}/progress/`,
+      payload,
+    );
+    return data;
+  },
+
+  /* ── Admin ── */
+
+  async getProgressSummary(groupId: number): Promise<AdminProgressSummary> {
+    const { data } = await api.get<AdminProgressSummary>(
+      `/groups/${groupId}/progress/summary/`,
+    );
     return data;
   },
 };

frontend/src/components/notifications/PaceNotification.tsx

@@ -1,119 +0,0 @@
-import { useEffect, useState } from "react";
-import { useTranslation } from "react-i18n-lite";
-import { groupsApi } from "../api/groups";
-import type { PaceStatus } from "../types/notifications";
-
-interface PaceNotificationProps {
-  ebookId?: number;
-}
-
-export function PaceNotification({ ebookId }: PaceNotificationProps) {
-  const { t } = useTranslation();
-  const [paceItems, setPaceItems] = useState<PaceStatus[]>([]);
-  const [loading, setLoading] = useState(true);
-  const [dismissed, setDismissed] = useState<Set<string>>(new Set());
-
-  useEffect(() => {
-    const load = async () => {
-      try {
-        const data = await groupsApi.getPaceStatus(ebookId);
-        setPaceItems(data);
-      } catch {
-        // Silently fail — notifications are non-critical
-      } finally {
-        setLoading(false);
-      }
-    };
-    void load();
-  }, [ebookId]);
-
-  const handleDismiss = async (meetingId: number, itemEbookId: number) => {
-    const key = `${meetingId}-${itemEbookId}`;
-    setDismissed((prev) => new Set(prev).add(key));
-    try {
-      await groupsApi.dismissPaceNotification(meetingId, itemEbookId);
-    } catch {
-      // Best effort dismissal
-    }
-  };
-
-  if (loading || paceItems.length === 0) return null;
-
-  const visibleItems = paceItems.filter(
-    (p) => !dismissed.has(`${p.meeting_id}-${p.ebook_id}`),
-  );
-  if (visibleItems.length === 0) return null;
-
-  return (
-    <div style={{ display: "flex", flexDirection: "column", gap: 8, padding: "12px 0" }}>
-      {visibleItems.map((item) => {
-        const isBehind = item.status === "behind";
-        const isAhead = item.status === "ahead" || item.status === "completed";
-        const isOnTrack = item.status === "on_track";
-
-        const bgColor = isBehind ? "#fde8e8" : isAhead ? "#d4edda" : "#e8f4fd";
-        const borderColor = isBehind ? "#e74c3c" : isAhead ? "#27ae60" : "#3498db";
-        const textColor = isBehind ? "#a71d2a" : isAhead ? "#155724" : "#0c5460";
-
-        return (
-          <div
-            key={`${item.meeting_id}-${item.ebook_id}`}
-            style={{
-              background: bgColor,
-              border: `1px solid ${borderColor}`,
-              borderRadius: 8,
-              padding: "12px 16px",
-              display: "flex",
-              alignItems: "flex-start",
-              justifyContent: "space-between",
-              gap: 12,
-            }}
-          >
-            <div style={{ flex: 1 }}>
-              <div style={{ fontSize: 14, fontWeight: 600, color: textColor, marginBottom: 4 }}>
-                {isBehind
-                  ? `Behind schedule — catch up ${item.sections_to_catch_up} section${item.sections_to_catch_up !== 1 ? "s" : ""}`
-                  : isOnTrack
-                    ? "On track — keep going!"
-                    : item.status === "completed"
-                      ? "Meeting target completed!"
-                      : "Ahead of schedule — great job!"}
-              </div>
-              <div style={{ fontSize: 13, color: textColor, opacity: 0.85 }}>
-                {item.meeting_title || `Target: ${item.target_section_label || `Section ${item.target_section}`}`}
-                {" — "}
-                {item.ebook_title}
-              </div>
-              <div style={{ fontSize: 12, color: textColor, opacity: 0.7, marginTop: 2 }}>
-                {isBehind
-                  ? `Currently at section ${item.current_section}, need section ${item.target_section}`
-                  : `Section ${item.current_section} of ${item.target_section}`}
-                {item.days_until_meeting > 0 &&
-                  ` · ${item.days_until_meeting} day${item.days_until_meeting !== 1 ? "s" : ""} until meeting`}
-                {item.days_until_meeting === 0 && " · Meeting today"}
-              </div>
-            </div>
-            <button
-              type="button"
-              onClick={() => handleDismiss(item.meeting_id, item.ebook_id)}
-              style={{
-                background: "none",
-                border: "none",
-                color: textColor,
-                fontSize: 20,
-                cursor: "pointer",
-                padding: "0 4px",
-                lineHeight: 1,
-                opacity: 0.6,
-                flexShrink: 0,
-              }}
-              title="Dismiss"
-            >
-              ×
-            </button>
-          </div>
-        );
-      })}
-    </div>
-  );
-}

frontend/src/components/notifications/ReadingPaceBanner.tsx

@@ -1,71 +0,0 @@
-import { useEffect, useState } from "react";
-import { groupsApi } from "../../api/groups";
-import type { PaceStatus } from "../../types/notifications";
-
-interface ReadingPaceBannerProps {
-  ebookId: number;
-  currentSection: number;
-}
-
-export function ReadingPaceBanner({ ebookId, currentSection }: ReadingPaceBannerProps) {
-  const [paceItems, setPaceItems] = useState<PaceStatus[]>([]);
-
-  useEffect(() => {
-    const load = async () => {
-      try {
-        const data = await groupsApi.getPaceStatus(ebookId);
-        setPaceItems(data);
-      } catch {
-        // Silently fail
-      }
-    };
-    void load();
-  }, [ebookId, currentSection]);
-
-  if (paceItems.length === 0) return null;
-
-  // Only show if user is one section away from target
-  const relevantItems = paceItems.filter(
-    (p) => Math.abs(p.target_section - p.current_section) <= 1 && p.status !== "completed",
-  );
-
-  if (relevantItems.length === 0) return null;
-
-  return (
-    <div
-      style={{
-        background: "linear-gradient(135deg, #667eea 0%, #764ba2 100%)",
-        color: "#fff",
-        padding: "10px 16px",
-        fontSize: 13,
-        fontWeight: 500,
-        textAlign: "center",
-        display: "flex",
-        alignItems: "center",
-        justifyContent: "center",
-        gap: 8,
-        flexWrap: "wrap",
-        position: "sticky",
-        top: 0,
-        zIndex: 10,
-      }}
-    >
-      {relevantItems.map((item) => {
-        const isAlmostThere = item.sections_to_catch_up === 1;
-        const isAtTarget = item.sections_to_catch_up === 0;
-
-        return (
-          <span key={item.meeting_id}>
-            {isAtTarget
-              ? `You've reached the target for ${item.meeting_title || `Section ${item.target_section}`}!`
-              : isAlmostThere
-                ? `Almost there! Just 1 section to go for ${item.meeting_title || `Section ${item.target_section}`}.`
-                : `You should be on ${item.target_section_label || `Section ${item.target_section}`} by the upcoming meeting.`}
-            {item.days_until_meeting > 0 &&
-              ` (${item.days_until_meeting} day${item.days_until_meeting !== 1 ? "s" : ""} left)`}
-          </span>
-        );
-      })}
-    </div>
-  );
-}

frontend/src/components/reader/EpubReadingView.tsx

@@ -22,7 +22,6 @@ import { SelectionPopover } from "./SelectionPopover";
 import { BookMarkersPanel } from "./BookMarkersPanel";
 import { BookmarkReaderRail } from "./BookmarkReaderRail";
 import { ResumeReadingButton } from "./ResumeReadingButton";
-import { ReadingPaceBanner } from "../notifications/ReadingPaceBanner";
 import type { MarkerEntry } from "@/types";
 
 const ReaderToolbar = lazy(() => import("./ReaderToolbar"));
@@ -131,10 +130,6 @@ export function EpubReadingView({ book, bookId, initialEpubLocation }: EpubReadi
 
   return (
     <ReaderSuspenseShell theme={settings.theme}>
-        <ReadingPaceBanner
-          ebookId={bookId}
-          currentSection={tocItems.length > 0 ? Math.max(1, Math.ceil((progress / 100) * tocItems.length)) : 0}
-        />
         <ReaderToolbar
           bookTitle={book.title}
           chapterTitle={chapterTitle || t("reader.reading")}

frontend/src/components/reader/PdfReadingView.tsx

@@ -24,7 +24,6 @@ import { BookmarkReaderRail } from "./BookmarkReaderRail";
 import { ResumeReadingButton } from "./ResumeReadingButton";
 import { PdfLimitationsNotice } from "./PdfLimitationsNotice";
 import { PdfViewer } from "./PdfViewer";
-import { ReadingPaceBanner } from "../notifications/ReadingPaceBanner";
 import type { MarkerEntry } from "@/types";
 
 const ReaderToolbar = lazy(() => import("./ReaderToolbar"));
@@ -171,10 +170,6 @@ export function PdfReadingView({ book, bookId, initialAnchor }: PdfReadingViewPr
 
   return (
     <ReaderSuspenseShell theme={settings.theme}>
-        <ReadingPaceBanner
-          ebookId={bookId}
-          currentSection={currentPage}
-        />
         <ReaderToolbar
           bookTitle={book.title}
           chapterTitle={chapterTitle || t("reader.reading")}

frontend/src/pages/GroupDetail.tsx

@@ -0,0 +1,381 @@
+import React, { useCallback, useEffect, useState } from "react";
+import { useNavigate, useParams } from "react-router-dom";
+import { useTranslation } from "react-i18n-lite";
+import { groupsApi } from "../api/groups";
+import type {
+  AdminProgressSummary,
+  MemberProgressEntry,
+  ReadingGroupDetail,
+} from "../types/groups";
+import { useMediaQuery, BREAKPOINTS } from "../hooks/useMediaQuery";
+
+function isDetail(entry: MemberProgressEntry): entry is { user_id: number; is_public: boolean; id: number } {
+  return "id" in entry && "is_public" in entry;
+}
+
+export function GroupDetailPage() {
+  const { t } = useTranslation();
+  const { id } = useParams<{ id: string }>();
+  const navigate = useNavigate();
+  const isMobile = useMediaQuery(BREAKPOINTS.md);
+
+  const [group, setGroup] = useState<ReadingGroupDetail | null>(null);
+  const [progressEntries, setProgressEntries] = useState<MemberProgressEntry[]>([]);
+  const [adminSummary, setAdminSummary] = useState<AdminProgressSummary | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+  const [tab, setTab] = useState<"progress" | "admin">("progress");
+
+  const isAdmin = group?.members.some(
+    (m) => m.user_id === (group as ReadingGroupDetail & { _myUserId?: number })._myUserId && m.role === "admin",
+  );
+
+  const loadGroup = useCallback(async () => {
+    if (!id) return;
+    setLoading(true);
+    setError(null);
+    try {
+      const groupId = Number(id);
+      if (Number.isNaN(groupId)) {
+        setError(t("groupDetail.invalidId") ?? "Invalid group ID");
+        return;
+      }
+      const [groupData, progressData] = await Promise.all([
+        groupsApi.getGroup(groupId),
+        groupsApi.getMembersProgress(groupId).catch(() => [] as MemberProgressEntry[]),
+      ]);
+      setGroup(groupData);
+      setProgressEntries(progressData);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load group");
+    } finally {
+      setLoading(false);
+    }
+  }, [id, t]);
+
+  const loadAdminSummary = useCallback(async () => {
+    if (!id || !isAdmin) return;
+    try {
+      const summary = await groupsApi.getProgressSummary(Number(id));
+      setAdminSummary(summary);
+    } catch {
+      // Admin summary is optional
+    }
+  }, [id, isAdmin]);
+
+  useEffect(() => {
+    void loadGroup();
+  }, [loadGroup]);
+
+  useEffect(() => {
+    if (tab === "admin") {
+      void loadAdminSummary();
+    }
+  }, [tab, loadAdminSummary]);
+
+  const handleJoin = useCallback(async () => {
+    if (!id) return;
+    try {
+      await groupsApi.joinGroup(Number(id));
+      void loadGroup();
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to join");
+    }
+  }, [id, loadGroup]);
+
+  const handleLeave = useCallback(async () => {
+    if (!id) return;
+    try {
+      await groupsApi.leaveGroup(Number(id));
+      navigate("/groups");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to leave");
+    }
+  }, [id, navigate]);
+
+  const containerStyle: React.CSSProperties = {
+    maxWidth: 720,
+    margin: "0 auto",
+    padding: isMobile ? 16 : 24,
+    minHeight: "100vh",
+    background: "#f8f9fa",
+  };
+
+  const backButtonStyle: React.CSSProperties = {
+    display: "inline-flex",
+    alignItems: "center",
+    gap: 4,
+    padding: isMobile ? "10px 16px" : "8px 16px",
+    borderRadius: 8,
+    border: "1px solid #e5e7eb",
+    background: "#fff",
+    color: "#374151",
+    fontSize: isMobile ? 15 : 14,
+    cursor: "pointer",
+    marginBottom: 20,
+    minHeight: 44,
+  };
+
+  const tabBarStyle: React.CSSProperties = {
+    display: "flex",
+    gap: 0,
+    marginBottom: 20,
+    borderBottom: "2px solid #e5e7eb",
+  };
+
+  const tabStyle = (active: boolean): React.CSSProperties => ({
+    padding: "10px 20px",
+    fontSize: 14,
+    fontWeight: active ? 600 : 400,
+    color: active ? "#4f46e5" : "#6b7280",
+    background: "transparent",
+    border: "none",
+    borderBottom: active ? "2px solid #4f46e5" : "2px solid transparent",
+    cursor: "pointer",
+    marginBottom: -2,
+  });
+
+  if (loading) {
+    return (
+      <div style={containerStyle}>
+        <div style={{ height: 32, width: 100, background: "#e5e7eb", borderRadius: 6, marginBottom: 20 }} />
+        <div style={{ height: 28, width: "50%", background: "#e5e7eb", borderRadius: 6, marginBottom: 16 }} />
+        {[1, 2, 3].map((i) => (
+          <div key={i} style={{ height: 60, background: "#e5e7eb", borderRadius: 8, marginBottom: 8 }} />
+        ))}
+      </div>
+    );
+  }
+
+  if (error || !group) {
+    return (
+      <div style={containerStyle}>
+        <button onClick={() => navigate("/groups")} style={backButtonStyle}>
+          ← {t("groupDetail.back") ?? "Back"}
+        </button>
+        <div style={{ textAlign: "center", padding: "60px 20px" }}>
+          <div style={{ fontSize: 48, marginBottom: 16 }}>😕</div>
+          <p style={{ color: "#6b7280", fontSize: 16 }}>
+            {error ?? (t("groupDetail.notFound") ?? "Group not found")}
+          </p>
+        </div>
+      </div>
+    );
+  }
+
+  const isMember = group.members.some((m) => {
+    // Determine membership by matching progress data — user_id can come from members list
+    // We check if there's a progress entry with an "id" (indicates own data)
+    return progressEntries.some((e) => "id" in e);
+  });
+
+  return (
+    <div style={containerStyle}>
+      <button onClick={() => navigate("/groups")} style={backButtonStyle}>
+        ← {t("groupDetail.back") ?? "Back to Groups"}
+      </button>
+
+      {/* Header */}
+      <div style={{ marginBottom: 20 }}>
+        <h1 style={{ fontSize: isMobile ? 20 : 24, fontWeight: 700, color: "#1f2937", margin: "0 0 4px" }}>
+          {group.name}
+        </h1>
+        <p style={{ fontSize: 14, color: "#6b7280", margin: 0 }}>
+          {group.ebook_title} {group.ebook_author ? `— ${group.ebook_author}` : ""}
+        </p>
+      </div>
+
+      {/* Group actions */}
+      <div style={{ display: "flex", gap: 10, marginBottom: 20, flexWrap: "wrap" }}>
+        {!isMember ? (
+          <button
+            onClick={() => void handleJoin()}
+            style={{
+              padding: "10px 20px", borderRadius: 10, border: "none", background: "#4f46e5",
+              color: "#fff", fontSize: 14, fontWeight: 600, cursor: "pointer",
+            }}
+          >
+            {t("groupDetail.join") ?? "Join Group"}
+          </button>
+        ) : (
+          <>
+            <span style={{
+              fontSize: 13, color: "#16a34a", background: "#dcfce7",
+              padding: "4px 12px", borderRadius: 999, display: "inline-flex", alignItems: "center",
+            }}>
+              ✓ {t("groupDetail.member") ?? "Member"}
+            </span>
+            {group.created_by_email !== undefined /* can't check identity here, but leave is always available for non-creators */ && (
+              <button
+                onClick={() => void handleLeave()}
+                style={{
+                  padding: "10px 20px", borderRadius: 10, border: "1px solid #fca5a5",
+                  background: "#fff", color: "#b91c1c", fontSize: 14, cursor: "pointer",
+                }}
+              >
+                {t("groupDetail.leave") ?? "Leave Group"}
+              </button>
+            )}
+          </>
+        )}
+      </div>
+
+      {group.description && (
+        <p style={{ fontSize: 14, color: "#4b5563", marginBottom: 20, lineHeight: 1.6, background: "#fff", padding: isMobile ? 12 : 16, borderRadius: 10, border: "1px solid #e5e7eb" }}>
+          {group.description}
+        </p>
+      )}
+
+      {/* Tabs */}
+      <div style={tabBarStyle}>
+        <button style={tabStyle(tab === "progress")} onClick={() => setTab("progress")}>
+          {t("groupDetail.progressTab") ?? "Progress"}
+        </button>
+        {isAdmin && (
+          <button style={tabStyle(tab === "admin")} onClick={() => setTab("admin")}>
+            {t("groupDetail.adminTab") ?? "Admin Summary"}
+          </button>
+        )}
+      </div>
+
+      {/* Progress tab */}
+      {tab === "progress" && (
+        <div>
+          {progressEntries.length === 0 ? (
+            <div style={{ textAlign: "center", padding: "40px 20px", color: "#9ca3af" }}>
+              <p>{t("groupDetail.noProgress") ?? "No progress data yet."}</p>
+            </div>
+          ) : (
+            progressEntries.map((entry) => {
+              const isPrivate = "is_public" in entry && entry.is_public === false && "note" in entry;
+              const hasDetail = isDetail(entry);
+
+              return (
+                <div
+                  key={entry.user_id}
+                  style={{
+                    background: "#fff", borderRadius: 10, padding: isMobile ? 12 : 16,
+                    marginBottom: 10, border: "1px solid #e5e7eb",
+                    boxShadow: "0 1px 3px rgba(0,0,0,0.04)",
+                  }}
+                >
+                  <div style={{ display: "flex", justifyContent: "space-between", alignItems: "center", marginBottom: 6 }}>
+                    <span style={{ fontSize: 15, fontWeight: 600, color: "#1f2937" }}>
+                      {entry.user_email}
+                      {hasDetail && " (you)"}
+                    </span>
+                    {isPrivate ? (
+                      <span style={{ fontSize: 12, color: "#9ca3af", fontStyle: "italic" }}>
+                        🔒 {t("groupDetail.private") ?? "Private"}
+                      </span>
+                    ) : "section_label" in entry && (
+                      <span style={{ fontSize: 13, color: "#4f46e5", fontWeight: 500 }}>
+                        {entry.section_label}
+                      </span>
+                    )}
+                  </div>
+
+                  {!isPrivate && "percentage" in entry && (
+                    <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
+                      <div style={{
+                        flex: 1, height: 8, borderRadius: 4, background: "#e5e7eb", overflow: "hidden",
+                      }}>
+                        <div style={{
+                          height: "100%",
+                          width: `${Math.min(100, entry.percentage)}%`,
+                          background: hasDetail ? "#4f46e5" : "#818cf8",
+                          borderRadius: 4,
+                          transition: "width 0.3s ease",
+                        }} />
+                      </div>
+                      <span style={{ fontSize: 13, fontWeight: 600, color: "#374151", whiteSpace: "nowrap" }}>
+                        {Math.round(entry.percentage)}%
+                      </span>
+                    </div>
+                  )}
+
+                  {hasDetail && entry.last_position && Object.keys(entry.last_position).length > 0 && (
+                    <div style={{ marginTop: 8, fontSize: 12, color: "#9ca3af" }}>
+                      {t("groupDetail.lastPosition") ?? "Last position"}: {JSON.stringify(entry.last_position)}
+                    </div>
+                  )}
+                </div>
+              );
+            })
+          )}
+        </div>
+      )}
+
+      {/* Admin tab */}
+      {tab === "admin" && adminSummary && (
+        <div>
+          <div style={{
+            display: "grid",
+            gridTemplateColumns: "repeat(auto-fit, minmax(140px, 1fr))",
+            gap: 12,
+            marginBottom: 24,
+          }}>
+            <StatCard
+              label={t("groupDetail.totalMembers") ?? "Members"}
+              value={String(adminSummary.total_members)}
+            />
+            <StatCard
+              label={t("groupDetail.started") ?? "Started"}
+              value={String(adminSummary.members_started)}
+            />
+            <StatCard
+              label={t("groupDetail.finished") ?? "Finished"}
+              value={String(adminSummary.members_finished)}
+            />
+            <StatCard
+              label={t("groupDetail.avgProgress") ?? "Avg Progress"}
+              value={`${Math.round(adminSummary.average_percentage)}%`}
+            />
+            <StatCard
+              label={t("groupDetail.avgTime") ?? "Avg Time"}
+              value={`${adminSummary.average_time_spent_hours}h`}
+            />
+          </div>
+
+          <h3 style={{ fontSize: 15, fontWeight: 600, color: "#1f2937", marginBottom: 12 }}>
+            {t("groupDetail.memberDetails") ?? "Member Details"}
+          </h3>
+          {adminSummary.member_details.map((m) => (
+            <div
+              key={m.user_id}
+              style={{
+                background: "#fff", borderRadius: 10, padding: isMobile ? 12 : 14,
+                marginBottom: 8, border: "1px solid #e5e7eb",
+                display: "flex", justifyContent: "space-between", alignItems: "center",
+              }}
+            >
+              <div>
+                <span style={{ fontSize: 14, fontWeight: 500, color: "#1f2937" }}>{m.user_email}</span>
+                <span style={{ fontSize: 12, color: "#9ca3af", marginLeft: 8 }}>
+                  {m.is_public ? "👁" : "🔒"}
+                </span>
+              </div>
+              <div style={{ display: "flex", gap: 16, fontSize: 13, color: "#6b7280" }}>
+                <span>Section {m.current_section}</span>
+                <span style={{ fontWeight: 600, color: "#4f46e5" }}>{Math.round(m.percentage)}%</span>
+                <span>⏱ {Math.round(m.time_spent_seconds / 60)}m</span>
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}
+
+function StatCard({ label, value }: { label: string; value: string }) {
+  return (
+    <div style={{
+      background: "#fff", borderRadius: 10, padding: "14px 16px",
+      border: "1px solid #e5e7eb", textAlign: "center",
+    }}>
+      <div style={{ fontSize: 22, fontWeight: 700, color: "#4f46e5" }}>{value}</div>
+      <div style={{ fontSize: 12, color: "#6b7280", marginTop: 2 }}>{label}</div>
+    </div>
+  );
+}

frontend/src/pages/Library.tsx

@@ -19,7 +19,6 @@ import { useVoiceSearch } from "../hooks/useVoiceSearch";
 import { useMediaQuery, BREAKPOINTS } from "../hooks/useMediaQuery";
 import { SearchSuggestions } from "../components/search/SearchSuggestions";
 import { BookContextMenu } from "../components/BookContextMenu";
-import { PaceNotification } from "../components/notifications/PaceNotification";
 
 interface FilterState {
   genre: string;
@@ -243,6 +242,7 @@ export function LibraryPage() {
             <>
               <button onClick={() => navigate("/add")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.addBook")}>➕</button>
               <button onClick={() => navigate("/bookmarks-notes")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.bookmarks")}>🔖</button>
+              <button onClick={() => navigate("/groups")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title="Reading Groups">👥</button>
               <button onClick={() => navigate("/settings")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.settings")}>⚙️</button>
               <button onClick={logout} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.logout")}>🚪</button>
             </>
@@ -250,6 +250,7 @@ export function LibraryPage() {
             <>
               <button onClick={() => navigate("/add")} className="btn">+ {t("library.addBook")}</button>
               <button onClick={() => navigate("/bookmarks-notes")} className="btn btn-secondary">{t("library.bookmarks")}</button>
+              <button onClick={() => navigate("/groups")} className="btn btn-secondary">👥 Reading Groups</button>
               <button onClick={() => navigate("/settings")} className="btn btn-secondary">{t("library.settings")}</button>
               <button onClick={logout} className="btn btn-danger">{t("library.logout")}</button>
             </>
@@ -257,9 +258,6 @@ export function LibraryPage() {
         </div>
       </header>
 
-      {/* Pace Notifications */}
-      <PaceNotification />
-
       {/* Search Bar */}
       <div style={{ marginBottom: 16 }}>
         <div style={{ display: "flex", gap: 8, alignItems: "center" }}>

frontend/src/pages/ReadingGroups.tsx

@@ -0,0 +1,288 @@
+import React, { useCallback, useEffect, useState } from "react";
+import { useNavigate } from "react-router-dom";
+import { useTranslation } from "react-i18n-lite";
+import { groupsApi } from "../api/groups";
+import { booksApi } from "../api/books";
+import type { ReadingGroupSummary } from "../types/groups";
+import type { EBookListItem } from "../types/book";
+import { useMediaQuery, BREAKPOINTS } from "../hooks/useMediaQuery";
+
+export function ReadingGroupsPage() {
+  const { t } = useTranslation();
+  const navigate = useNavigate();
+  const isMobile = useMediaQuery(BREAKPOINTS.md);
+
+  const [groups, setGroups] = useState<ReadingGroupSummary[]>([]);
+  const [ebooks, setEbooks] = useState<EBookListItem[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+  const [showCreate, setShowCreate] = useState(false);
+  const [createName, setCreateName] = useState("");
+  const [createEbook, setCreateEbook] = useState<number | null>(null);
+  const [createDesc, setCreateDesc] = useState("");
+  const [creating, setCreating] = useState(false);
+
+  const loadGroups = useCallback(async () => {
+    try {
+      const data = await groupsApi.listGroups();
+      setGroups(data);
+      setError(null);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load groups");
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  const loadEbooks = useCallback(async () => {
+    try {
+      const data = await booksApi.getEBooks();
+      setEbooks(data);
+    } catch {
+      // Ebook list is optional; groups page still works without it
+    }
+  }, []);
+
+  useEffect(() => {
+    void loadGroups();
+    void loadEbooks();
+  }, [loadGroups, loadEbooks]);
+
+  const handleCreate = useCallback(async () => {
+    if (!createName.trim() || createEbook === null) return;
+    setCreating(true);
+    try {
+      await groupsApi.createGroup({
+        name: createName.trim(),
+        ebook: createEbook,
+        description: createDesc.trim(),
+      });
+      setShowCreate(false);
+      setCreateName("");
+      setCreateEbook(null);
+      setCreateDesc("");
+      void loadGroups();
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to create group");
+    } finally {
+      setCreating(false);
+    }
+  }, [createName, createEbook, createDesc, loadGroups]);
+
+  const containerStyle: React.CSSProperties = {
+    maxWidth: 720,
+    margin: "0 auto",
+    padding: isMobile ? 16 : 24,
+    minHeight: "100vh",
+    background: "#f8f9fa",
+  };
+
+  const headerBar: React.CSSProperties = {
+    display: "flex",
+    justifyContent: "space-between",
+    alignItems: "center",
+    marginBottom: 24,
+  };
+
+  const cardStyle: React.CSSProperties = {
+    background: "#fff",
+    borderRadius: 12,
+    padding: isMobile ? 14 : 18,
+    marginBottom: 12,
+    cursor: "pointer",
+    boxShadow: "0 1px 4px rgba(0,0,0,0.06)",
+    border: "1px solid #e5e7eb",
+  };
+
+  if (loading) {
+    return (
+      <div style={containerStyle}>
+        <div style={{ height: 24, width: 200, background: "#e5e7eb", borderRadius: 6, marginBottom: 24 }} />
+        {[1, 2, 3].map((i) => (
+          <div key={i} style={{ ...cardStyle, cursor: "default" }}>
+            <div style={{ height: 20, width: "60%", background: "#e5e7eb", borderRadius: 4, marginBottom: 8 }} />
+            <div style={{ height: 14, width: "40%", background: "#e5e7eb", borderRadius: 4 }} />
+          </div>
+        ))}
+      </div>
+    );
+  }
+
+  return (
+    <div style={containerStyle}>
+      <div style={headerBar}>
+        <h1 style={{ fontSize: isMobile ? 20 : 24, fontWeight: 700, color: "#1f2937", margin: 0 }}>
+          📚 {t("readingGroups.title") ?? "Reading Groups"}
+        </h1>
+        <button
+          onClick={() => setShowCreate(true)}
+          style={{
+            padding: isMobile ? "10px 18px" : "8px 18px",
+            borderRadius: 10,
+            border: "none",
+            background: "#4f46e5",
+            color: "#fff",
+            fontSize: 14,
+            fontWeight: 600,
+            cursor: "pointer",
+            minHeight: 40,
+          }}
+        >
+          + {t("readingGroups.create") ?? "New Group"}
+        </button>
+      </div>
+
+      {error && (
+        <div style={{ padding: "12px 16px", background: "#fef2f2", borderRadius: 8, color: "#b91c1c", marginBottom: 16, fontSize: 14 }}>
+          {error}
+        </div>
+      )}
+
+      {/* Create modal */}
+      {showCreate && (
+        <div style={{
+          position: "fixed", inset: 0, background: "rgba(0,0,0,0.4)",
+          display: "flex", alignItems: "center", justifyContent: "center", zIndex: 100,
+        }}>
+          <div style={{
+            background: "#fff", borderRadius: 16, padding: 24, maxWidth: 420, width: "90%",
+            boxShadow: "0 10px 40px rgba(0,0,0,0.15)",
+          }}>
+            <h2 style={{ fontSize: 18, fontWeight: 700, marginBottom: 16, color: "#1f2937" }}>
+              {t("readingGroups.createTitle") ?? "Create Reading Group"}
+            </h2>
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.groupName") ?? "Group Name"}
+            </label>
+            <input
+              type="text"
+              value={createName}
+              onChange={(e) => setCreateName(e.target.value)}
+              placeholder={t("readingGroups.namePlaceholder") ?? "e.g., Book Club June"}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 14, boxSizing: "border-box",
+              }}
+            />
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.selectBook") ?? "Select Book"}
+            </label>
+            <select
+              value={createEbook ?? ""}
+              onChange={(e) => setCreateEbook(e.target.value ? Number(e.target.value) : null)}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 14, boxSizing: "border-box", background: "#fff",
+              }}
+            >
+              <option value="">-- {t("readingGroups.choose") ?? "Choose"} --</option>
+              {ebooks.map((eb) => (
+                <option key={eb.id} value={eb.id}>
+                  {eb.title} {eb.author ? `— ${eb.author}` : ""}
+                </option>
+              ))}
+            </select>
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.description") ?? "Description"} ({t("common.optional") ?? "optional"})
+            </label>
+            <textarea
+              value={createDesc}
+              onChange={(e) => setCreateDesc(e.target.value)}
+              rows={3}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 18, boxSizing: "border-box", resize: "vertical",
+              }}
+            />
+
+            <div style={{ display: "flex", gap: 10, justifyContent: "flex-end" }}>
+              <button
+                onClick={() => setShowCreate(false)}
+                style={{
+                  padding: "10px 20px", borderRadius: 8, border: "1px solid #d1d5db",
+                  background: "#fff", color: "#374151", fontSize: 14, cursor: "pointer",
+                }}
+              >
+                {t("common.cancel") ?? "Cancel"}
+              </button>
+              <button
+                onClick={() => void handleCreate()}
+                disabled={creating || !createName.trim() || createEbook === null}
+                style={{
+                  padding: "10px 20px", borderRadius: 8, border: "none",
+                  background: (!createName.trim() || createEbook === null) ? "#9ca3af" : "#4f46e5",
+                  color: "#fff", fontSize: 14, fontWeight: 600, cursor: (!createName.trim() || createEbook === null) ? "not-allowed" : "pointer",
+                }}
+              >
+                {creating ? (t("common.creating") ?? "Creating...") : (t("readingGroups.create") ?? "Create")}
+              </button>
+            </div>
+          </div>
+        </div>
+      )}
+
+      {/* Group list */}
+      {groups.length === 0 ? (
+        <div style={{ textAlign: "center", padding: "60px 20px", color: "#6b7280" }}>
+          <div style={{ fontSize: 48, marginBottom: 12 }}>📖</div>
+          <p style={{ fontSize: 16, marginBottom: 16 }}>
+            {t("readingGroups.empty") ?? "No reading groups yet. Create one to read together!"}
+          </p>
+        </div>
+      ) : (
+        groups.map((g) => (
+          <div
+            key={g.id}
+            style={cardStyle}
+            onClick={() => navigate(`/groups/${g.id}`)}
+          >
+            <div style={{ display: "flex", justifyContent: "space-between", alignItems: "flex-start" }}>
+              <div>
+                <h2 style={{ fontSize: isMobile ? 16 : 17, fontWeight: 600, color: "#1f2937", margin: "0 0 4px" }}>
+                  {g.name}
+                </h2>
+                <p style={{ fontSize: 13, color: "#6b7280", margin: "0 0 6px" }}>
+                  {g.ebook_title} {g.ebook_author ? `— ${g.ebook_author}` : ""}
+                </p>
+              </div>
+              <span style={{
+                fontSize: 12, color: "#4f46e5", background: "#eef2ff",
+                padding: "2px 10px", borderRadius: 999, whiteSpace: "nowrap",
+                minHeight: 24, display: "inline-flex", alignItems: "center",
+              }}>
+                {g.member_count} {g.member_count === 1
+                  ? (t("readingGroups.member") ?? "member")
+                  : (t("readingGroups.members") ?? "members")}
+              </span>
+            </div>
+
+            {g.my_progress && (
+              <div style={{ marginTop: 8, display: "flex", alignItems: "center", gap: 8 }}>
+                <div style={{
+                  flex: 1, height: 6, borderRadius: 3, background: "#e5e7eb", overflow: "hidden",
+                }}>
+                  <div style={{
+                    height: "100%", width: `${Math.min(100, g.my_progress.percentage)}%`,
+                    background: "#4f46e5", borderRadius: 3, transition: "width 0.3s ease",
+                  }} />
+                </div>
+                <span style={{ fontSize: 12, color: "#6b7280", whiteSpace: "nowrap" }}>
+                  {g.my_progress.section_label}
+                </span>
+              </div>
+            )}
+
+            {g.description && (
+              <p style={{ fontSize: 13, color: "#9ca3af", margin: "8px 0 0", lineHeight: 1.5 }}>
+                {g.description}
+              </p>
+            )}
+          </div>
+        ))
+      )}
+    </div>
+  );
+}

frontend/src/pages/Settings.tsx

@@ -2,9 +2,7 @@ import { useEffect, useState } from "react";
 import { useNavigate } from "react-router-dom";
 import { useTranslation } from "react-i18n-lite";
 import { booksApi } from "../api/books";
-import { groupsApi } from "../api/groups";
 import type { ReadingSettings } from "../types/book";
-import type { NotificationPreferences } from "../types/notifications";
 import type { SupportedLanguage } from "../locales";
 import { SimpleFormPageLayout } from "../components/layout/SimpleFormPageLayout";
 
@@ -19,7 +17,6 @@ export function SettingsPage() {
   const { t, language, setLanguage } = useTranslation();
   const navigate = useNavigate();
   const [settings, setSettings] = useState<ReadingSettings | null>(null);
-  const [notifPrefs, setNotifPrefs] = useState<NotificationPreferences | null>(null);
   const [loading, setLoading] = useState(true);
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -27,14 +24,7 @@ export function SettingsPage() {
 
   useEffect(() => {
     const load = async () => {
-      try {
+      try { const data = await booksApi.getSettings(); setSettings(data); }
-        const [data, notifData] = await Promise.all([
-          booksApi.getSettings(),
-          groupsApi.getPreferences(),
-        ]);
-        setSettings(data);
-        setNotifPrefs(notifData);
-      }
       catch (err) { setError(err instanceof Error ? err.message : t("settings.loadFailed")); }
       finally { setLoading(false); }
     };
@@ -42,15 +32,9 @@ export function SettingsPage() {
   }, [t]);
 
   const handleSave = async () => {
-    if (!settings || !notifPrefs) return;
+    if (!settings) return;
     setSaving(true); setError(null); setSuccess(false);
-    try {
+    try { await booksApi.updateSettings(settings); setSuccess(true); setTimeout(() => setSuccess(false), 2000); }
-      await Promise.all([
-        booksApi.updateSettings(settings),
-        groupsApi.updatePreferences(notifPrefs),
-      ]);
-      setSuccess(true); setTimeout(() => setSuccess(false), 2000);
-    }
     catch (err) { setError(err instanceof Error ? err.message : t("settings.saveFailed")); }
     finally { setSaving(false); }
   };
@@ -101,48 +85,6 @@ export function SettingsPage() {
           </div>
         </>}
 
-        {notifPrefs && <>
-          <div style={{ borderTop: "1px solid #e5e7eb", paddingTop: 20 }}>
-            <h3 style={{ fontSize: 16, fontWeight: 600, color: "#1f2937", marginBottom: 16 }}>
-              Notification Settings
-            </h3>
-
-            <div style={{ display: "flex", flexDirection: "column", gap: 12 }}>
-              <label style={{ display: "flex", alignItems: "center", gap: 10, fontSize: 14, color: "#374151", cursor: "pointer" }}>
-                <input
-                  type="checkbox"
-                  checked={notifPrefs.pace_notifications_enabled}
-                  onChange={(e) => setNotifPrefs({ ...notifPrefs, pace_notifications_enabled: e.target.checked })}
-                  style={{ width: 18, height: 18, cursor: "pointer" }}
-                />
-                Enable pace notifications
-              </label>
-
-              <label style={{ display: "flex", alignItems: "center", gap: 10, fontSize: 14, color: "#374151", cursor: "pointer" }}>
-                <input
-                  type="checkbox"
-                  checked={notifPrefs.reminder_enabled}
-                  onChange={(e) => setNotifPrefs({ ...notifPrefs, reminder_enabled: e.target.checked })}
-                  style={{ width: 18, height: 18, cursor: "pointer" }}
-                />
-                Enable pre-meeting reminders (24h before)
-              </label>
-
-              <div style={{ display: "flex", flexDirection: "column", gap: 8 }}>
-                <label style={{ fontSize: 14, fontWeight: 600, color: "#555" }}>Notification frequency</label>
-                <select
-                  value={notifPrefs.frequency}
-                  onChange={(e) => setNotifPrefs({ ...notifPrefs, frequency: e.target.value as NotificationPreferences["frequency"] })}
-                  style={{ padding: "10px 12px", borderRadius: 6, border: "1px solid #ddd", fontSize: 16, background: "#fff", outline: "none" }}
-                >
-                  <option value="daily">Daily</option>
-                  <option value="weekly">Weekly</option>
-                </select>
-              </div>
-            </div>
-          </div>
-        </>}
-
         <button onClick={handleSave} disabled={saving} style={{ padding: "12px 24px", borderRadius: 8, border: "none", background: "#1a1a2e", color: "#fff", fontSize: 16, fontWeight: 600, cursor: "pointer", opacity: saving ? 0.6 : 1, marginTop: 8 }}>{saving ? t("common.saving") : t("settings.saveSettings")}</button>
       </div>
     </SimpleFormPageLayout>

frontend/src/types/groups.ts

@@ -0,0 +1,104 @@
+/* ── Reading Groups ── */
+
+export interface MemberProgressPublic {
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  updated_at: string;
+}
+
+export interface MemberProgressDetail {
+  id: number;
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  last_position: Record<string, unknown>;
+  is_public: boolean;
+  updated_at: string;
+}
+
+export interface MemberProgressPrivateStub {
+  user_id: number;
+  user_email: string;
+  is_public: false;
+  note: string;
+}
+
+export type MemberProgressEntry =
+  | MemberProgressDetail
+  | MemberProgressPublic
+  | MemberProgressPrivateStub;
+
+export interface GroupMember {
+  id: number;
+  user_id: number;
+  user_email: string;
+  role: "member" | "admin";
+  joined_at: string;
+  progress: MemberProgressPublic | { is_public: false; note: string } | null;
+}
+
+export interface ReadingGroupSummary {
+  id: number;
+  name: string;
+  ebook: number;
+  ebook_title: string;
+  ebook_author: string;
+  created_by_email: string;
+  description: string;
+  member_count: number;
+  my_progress: {
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    section_label: string;
+  } | null;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface ReadingGroupDetail extends ReadingGroupSummary {
+  members: GroupMember[];
+}
+
+export interface CreateGroupPayload {
+  name: string;
+  ebook: number;
+  description?: string;
+}
+
+export interface UpdateProgressPayload {
+  current_section: number;
+  percentage?: number;
+  time_spent_delta?: number;
+  last_position?: Record<string, unknown>;
+  is_public?: boolean;
+}
+
+export interface AdminProgressSummary {
+  group_id: number;
+  group_name: string;
+  ebook_title: string;
+  total_members: number;
+  members_started: number;
+  members_finished: number;
+  average_percentage: number;
+  average_time_spent_hours: number;
+  member_details: {
+    user_id: number;
+    user_email: string;
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    is_public: boolean;
+    updated_at: string;
+  }[];
+}

frontend/src/types/notifications.ts

@@ -1,65 +0,0 @@
-export interface PaceStatus {
-  meeting_id: number;
-  meeting_title: string;
-  scheduled_at: string;
-  target_section: number;
-  target_section_label: string;
-  current_section: number;
-  ahead_behind_delta: number;
-  status: "ahead" | "behind" | "on_track" | "completed";
-  days_until_meeting: number;
-  sections_to_catch_up: number;
-  ebook_id: number;
-  ebook_title: string;
-}
-
-export interface NotificationPreferences {
-  pace_notifications_enabled: boolean;
-  reminder_enabled: boolean;
-  frequency: "daily" | "weekly";
-}
-
-export interface MeetingReminder {
-  meeting_id: number;
-  meeting_title: string;
-  scheduled_at: string;
-  target_section: number;
-  target_section_label: string;
-  group_name: string;
-  hours_until: number;
-  ebook_id: number;
-  ebook_title: string;
-}
-
-export interface ReadingGroup {
-  id: number;
-  name: string;
-  description: string;
-  book: number | null;
-  ebook: number | null;
-  created_by: number;
-  created_at: string;
-  member_count: number;
-  meeting_count: number;
-}
-
-export interface GroupMeeting {
-  id: number;
-  group: number;
-  group_name: string;
-  title: string;
-  scheduled_at: string;
-  target_section: number;
-  target_section_label: string;
-  created_at: string;
-}
-
-export interface GroupMembership {
-  id: number;
-  user: number;
-  user_email: string;
-  group: number;
-  group_name: string;
-  role: "admin" | "member";
-  joined_at: string;
-}

packages/shared/src/types.ts

@@ -216,3 +216,35 @@ export interface ApiError {
   detail?: string;
   [key: string]: unknown;
 }
+
+// ---- Reading Groups ----
+
+export interface ReadingGroupSummary {
+  id: number;
+  name: string;
+  ebook: number;
+  ebook_title: string;
+  ebook_author: string;
+  created_by_email: string;
+  description: string;
+  member_count: number;
+  my_progress: {
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    section_label: string;
+  } | null;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface MemberProgressPublic {
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  updated_at: string;
+}

packages/shared/src/utils.ts

@@ -114,4 +114,13 @@ export const API_ENDPOINTS = {
     bookmarkDetail: (id: string) => `/api/annotations/bookmarks/${id}/`,
     noteDetail: (id: string) => `/api/annotations/notes/${id}/`,
   },
+  groups: {
+    list: "/api/groups/",
+    detail: (id: number) => `/api/groups/${id}/`,
+    membersProgress: (id: number) => `/api/groups/${id}/members/progress/`,
+    myProgress: (id: number) => `/api/groups/${id}/progress/`,
+    progressSummary: (id: number) => `/api/groups/${id}/progress/summary/`,
+    join: (id: number) => `/api/groups/${id}/join/`,
+    leave: (id: number) => `/api/groups/${id}/leave/`,
+  },
 } as const;