from django.conf import settings
from django.db import models


class Bookmark(models.Model):
    """A user bookmark at a specific page in a document."""
    document = models.ForeignKey(
        "documents.Document",
        on_delete=models.CASCADE,
        related_name="bookmarks",
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="bookmarks",
    )
    page = models.PositiveIntegerField()
    label = models.CharField(max_length=300, blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "reading_bookmark"
        ordering = ["page"]
        unique_together = [["document", "user", "page"]]

    def __str__(self) -> str:
        return f"{self.document.title} p.{self.page}"


class Highlight(models.Model):
    """A highlighted passage in a document."""
    document = models.ForeignKey(
        "documents.Document",
        on_delete=models.CASCADE,
        related_name="highlights",
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="highlights",
    )
    page = models.PositiveIntegerField()
    color = models.CharField(max_length=20, default="yellow")
    text = models.TextField()
    note = models.TextField(blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "reading_highlight"
        ordering = ["-created_at"]

    def __str__(self) -> str:
        return f"Highlight on {self.document.title} p.{self.page}"


class ReadingProgress(models.Model):
    """Tracks the user's reading progress through a document."""
    document = models.ForeignKey(
        "documents.Document",
        on_delete=models.CASCADE,
        related_name="reading_progress",
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="reading_progress",
    )
    current_page = models.PositiveIntegerField(default=1)
    total_pages = models.PositiveIntegerField(default=0)
    percentage = models.FloatField(default=0.0)
    last_read_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "reading_progress"
        unique_together = [["document", "user"]]
        verbose_name_plural = "Reading progress"

    def __str__(self) -> str:
        return f"{self.document.title} — {self.percentage:.0f}%"

    def save(self, *args, **kwargs):
        if self.total_pages > 0:
            self.percentage = round((self.current_page / self.total_pages) * 100, 1)
        super().save(*args, **kwargs)