from adrf.serializers import (
    ModelSerializer, SerializerMethodField,
)
from .models import Course, Chapter, ChapterContent, CourseMaterial


class ChapterSerializer(ModelSerializer):
    video_poster_url = SerializerMethodField()
    video_local_url = SerializerMethodField()

    class Meta:
        model = Chapter
        fields = ['id', 'title', 'sort_order', 'duration', 'is_free', 'video_url', 'video_source', 'video_local_url', 'video_poster_url', 'created_at', 'updated_at']

    async def get_video_poster_url(self, obj):
        if obj.video_poster:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.video_poster.url)
            return obj.video_poster.url
        return ''

    async def get_video_local_url(self, obj):
        if obj.video_local:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.video_local.url)
            return obj.video_local.url
        return ''


class ChapterContentSerializer(ModelSerializer):
    class Meta:
        model = ChapterContent
        fields = ['id', 'chapter', 'content_md', 'content_html', 'md_file_path', 'updated_at']


class MaterialSerializer(ModelSerializer):
    file_url = SerializerMethodField()
    file_size_display = SerializerMethodField()
    file_type_display = SerializerMethodField()

    class Meta:
        model = CourseMaterial
        fields = ['id', 'title', 'file_url', 'file_type', 'file_type_display', 'file_size', 'file_size_display', 'download_count', 'sort_order', 'created_at']

    async def get_file_url(self, obj):
        if obj.file:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.file.url)
            return obj.file.url
        return ''

    async def get_file_size_display(self, obj):
        size = obj.file_size
        if size < 1024:
            return f'{size} B'
        elif size < 1024 * 1024:
            return f'{size / 1024:.1f} KB'
        else:
            return f'{size / (1024 * 1024):.1f} MB'

    async def get_file_type_display(self, obj):
        type_map = {
            'pdf': 'PDF',
            'code': '代码',
            'doc': '文档',
            'video': '视频',
            'dataset': '数据集',
            'zip': '压缩包',
            'other': '其他',
        }
        return type_map.get(obj.file_type, '其他')


class ChapterSerializer(ModelSerializer):
    video_poster_url = SerializerMethodField()

    class Meta:
        model = Chapter
        fields = ['id', 'title', 'sort_order', 'duration', 'is_free', 'video_url', 'video_poster_url', 'created_at', 'updated_at']

    async def get_video_poster_url(self, obj):
        if obj.video_poster:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.video_poster.url)
            return obj.video_poster.url
        return ''


class ChapterContentSerializer(ModelSerializer):
    class Meta:
        model = ChapterContent
        fields = ['id', 'chapter', 'content_md', 'content_html', 'md_file_path', 'updated_at']


class CourseListSerializer(ModelSerializer):
    author_name = SerializerMethodField()
    chapters_count = SerializerMethodField()
    students_count = SerializerMethodField()
    cover_image_url = SerializerMethodField()

    class Meta:
        model = Course
        fields = [
            'id', 'title', 'description', 'category', 'level',
            'cover_image_url', 'color', 'icon_name', 'author_name',
            'chapters_count', 'students_count', 'status',
            'sort_order', 'is_hot', 'is_new', 'created_at', 'updated_at',
        ]

    async def get_chapters_count(self, obj):
        return await obj.chapters.acount()

    async def get_students_count(self, obj):
        return 0

    async def get_cover_image_url(self, obj):
        if obj.cover_image:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.cover_image.url)
            return obj.cover_image.url
        return ''

    async def get_author_name(self, obj):
        if obj.author:
            return obj.author.get_full_name() or obj.author.username
        return ''


class CourseDetailSerializer(ModelSerializer):
    author_name = SerializerMethodField()
    chapters = ChapterSerializer(many=True, read_only=True)
    chapters_count = SerializerMethodField()
    students_count = SerializerMethodField()
    cover_image_url = SerializerMethodField()

    class Meta:
        model = Course
        fields = [
            'id', 'title', 'description', 'category', 'level',
            'cover_image_url', 'color', 'icon_name', 'author_name',
            'chapters', 'chapters_count', 'students_count', 'status',
            'sort_order', 'is_hot', 'is_new', 'created_at', 'updated_at',
        ]

    async def get_chapters_count(self, obj):
        return await obj.chapters.acount()

    async def get_students_count(self, obj):
        return 0

    async def get_cover_image_url(self, obj):
        if obj.cover_image:
            request = self.context.get('request')
            if request:
                return request.build_absolute_uri(obj.cover_image.url)
            return obj.cover_image.url
        return ''

    async def get_author_name(self, obj):
        if obj.author:
            return obj.author.get_full_name() or obj.author.username
        return ''


class CourseCreateUpdateSerializer(ModelSerializer):
    class Meta:
        model = Course
        fields = ['title', 'description', 'category', 'level', 'cover_image', 'color', 'icon_name', 'status', 'sort_order', 'is_hot', 'is_new']

    async def acreate(self, validated_data):
        validated_data['author'] = self.context['request'].user
        return await super().acreate(validated_data)


class CourseManageSerializer(ModelSerializer):
    author_name = SerializerMethodField()
    chapters_count = SerializerMethodField()

    class Meta:
        model = Course
        fields = [
            'id', 'title', 'category', 'level', 'status',
            'sort_order', 'is_hot', 'is_new', 'chapters_count',
            'author_name', 'created_at', 'updated_at',
        ]

    async def get_chapters_count(self, obj):
        return await obj.chapters.acount()

    async def get_author_name(self, obj):
        if obj.author:
            return obj.author.get_full_name() or obj.author.username
        return ''