from rest_framework import serializers

from apps.books.models import Book, Chapter, ReadingProgress


class BookSerializer(serializers.ModelSerializer):
    """Serialize Book data."""

    class Meta:
        model = Book
        fields = [
            "id",
            "title",
            "author",
            "total_pages",
            "cover_image",
            "created_at",
            "updated_at",
        ]
        read_only_fields = ["id", "created_at", "updated_at"]


class BookListSerializer(serializers.ModelSerializer):
    """Lightweight serializer for list views (excludes heavy fields)."""

    class Meta:
        model = Book
        fields = ["id", "title", "author", "total_pages", "cover_image"]


class ChapterSummarySerializer(serializers.ModelSerializer):
    """Compact serializer for TOC listing — no content body."""

    class Meta:
        model = Chapter
        fields = ["id", "book", "title", "number"]


class ChapterDetailSerializer(serializers.ModelSerializer):
    """Full serializer with chapter content for reading view."""

    class Meta:
        model = Chapter
        fields = ["id", "book", "title", "number", "content", "created_at", "updated_at"]
        read_only_fields = ["id", "created_at", "updated_at"]


class ReadingProgressSerializer(serializers.ModelSerializer):
    """Serialize reading progress for a book."""

    class Meta:
        model = ReadingProgress
        fields = [
            "id",
            "book",
            "current_chapter",
            "current_position",
            "percentage",
            "updated_at",
        ]
        read_only_fields = ["id", "updated_at"]

    def validate_percentage(self, value: float) -> float:
        if value < 0.0 or value > 100.0:
            raise serializers.ValidationError("Percentage must be between 0 and 100.")
        return value

    def validate_current_chapter(self, value: int) -> int:
        if value < 1:
            raise serializers.ValidationError("Chapter number must be positive.")
        return value