from rest_framework import serializers
from django.conf import settings
from .models import Competition, CompetitionEnrollment, ScoreDimension, Project, ProjectFile, Score, Comment, HomePageConfig, CarouselItem
from shop.serializers import WeChatUserSerializer


def _media_url(file_field):
    """返回 media 文件的相对路径，避免 build_absolute_uri 生成容器内部地址"""
    if file_field and file_field.name:
        return settings.MEDIA_URL + file_field.name
    return None


class CarouselItemSerializer(serializers.ModelSerializer):
    display_image = serializers.SerializerMethodField()
    
    class Meta:
        model = CarouselItem
        fields = ['id', 'carousel_type', 'image', 'image_url', 'display_image', 
                  'title', 'subtitle', 'status', 'status_color', 'date', 'location', 
                  'order', 'is_active']
    
    def get_display_image(self, obj):
        return _media_url(obj.image) or obj.image_url


class HomePageConfigSerializer(serializers.ModelSerializer):
    display_banner = serializers.SerializerMethodField()
    carousel1_items = serializers.SerializerMethodField()
    carousel2_items = serializers.SerializerMethodField()

    class Meta:
        model = HomePageConfig
        fields = ['id', 'banner_image', 'banner_image_url', 'display_banner',
                  'main_title', 'carousel1_title', 'carousel2_title',
                  'organizer', 'undertaker', 'carousel1_items', 'carousel2_items']

    def get_display_banner(self, obj):
        return _media_url(obj.banner_image) or obj.banner_image_url

    def get_carousel1_items(self, obj):
        items = CarouselItem.objects.filter(carousel_type='carousel1', is_active=True)
        return CarouselItemSerializer(items, many=True, context=self.context).data

    def get_carousel2_items(self, obj):
        items = CarouselItem.objects.filter(carousel_type='carousel2', is_active=True)
        return CarouselItemSerializer(items, many=True, context=self.context).data


class ScoreDimensionSerializer(serializers.ModelSerializer):
    class Meta:
        model = ScoreDimension
        fields = ['id', 'name', 'description', 'weight', 'max_score', 'order']


class CompetitionSerializer(serializers.ModelSerializer):
    score_dimensions = ScoreDimensionSerializer(many=True, read_only=True)
    display_cover_image = serializers.SerializerMethodField()
    status_display = serializers.CharField(source='get_status_display', read_only=True)

    class Meta:
        model = Competition
        fields = ['id', 'title', 'description', 'rule_description', 'condition_description',
                  'cover_image', 'cover_image_url', 'display_cover_image',
                  'start_time', 'end_time', 'status', 'project_visibility', 'status_display', 'is_active',
                  'score_dimensions', 'created_at']

    def get_display_cover_image(self, obj):
        return _media_url(obj.cover_image) or obj.cover_image_url


class CompetitionEnrollmentSerializer(serializers.ModelSerializer):
    user = WeChatUserSerializer(read_only=True)
    
    class Meta:
        model = CompetitionEnrollment
        fields = ['id', 'competition', 'user', 'role', 'status', 'created_at']
        read_only_fields = ['status']


class ProjectFileSerializer(serializers.ModelSerializer):
    class Meta:
        model = ProjectFile
        fields = ['id', 'project', 'file_type', 'file', 'file_url', 'name', 'created_at']

    def validate_file(self, value):
        if not value:
            return value
        limit_mb = 50
        if value.size > limit_mb * 1024 * 1024:
            raise serializers.ValidationError(f"文件大小不能超过 {limit_mb}MB")
        return value


class ProjectSerializer(serializers.ModelSerializer):
    files = ProjectFileSerializer(many=True, read_only=True)
    contestant_info = serializers.SerializerMethodField()
    display_cover_image = serializers.SerializerMethodField()
    
    class Meta:
        model = Project
        fields = ['id', 'competition', 'contestant', 'title', 'description', 'team_info', 
                  'cover_image', 'cover_image_url', 'display_cover_image',
                  'status', 'final_score', 'files', 'contestant_info', 'created_at']
        read_only_fields = ['final_score', 'contestant']

    def get_contestant_info(self, obj):
        return {
            "nickname": obj.contestant.user.nickname,
            "avatar_url": obj.contestant.user.avatar_url
        }

    def get_display_cover_image(self, obj):
        return _media_url(obj.cover_image) or obj.cover_image_url


class ScoreSerializer(serializers.ModelSerializer):
    judge_name = serializers.CharField(source='judge.user.nickname', read_only=True)
    dimension_name = serializers.CharField(source='dimension.name', read_only=True)
    
    class Meta:
        model = Score
        fields = ['id', 'project', 'judge', 'dimension', 'score', 'judge_name', 'dimension_name', 'created_at']
        read_only_fields = ['judge']


class CommentSerializer(serializers.ModelSerializer):
    judge_name = serializers.CharField(source='judge.user.nickname', read_only=True)
    score = serializers.SerializerMethodField()
    
    class Meta:
        model = Comment
        fields = ['id', 'project', 'judge', 'content', 'judge_name', 'created_at', 'score']
        read_only_fields = ['judge']

    def get_score(self, obj):
        scores = Score.objects.filter(project=obj.project, judge=obj.judge)
        if not scores.exists():
            return None
        total_score = 0
        total_weight = 0
        for score in scores:
            total_score += score.score * score.dimension.weight
            total_weight += score.dimension.weight
        if total_weight > 0:
            return round(total_score / total_weight, 1)
        return None