from rest_framework import serializers
from django.db.models import Avg
from core.apps.accounts.choices import AccountType
from core.apps.api.models import AdModel, AdVariantModel, CategoryModel, AdImageModel, AdOptionModel
from core.apps.accounts.models import UserLike
from core.apps.api.choices import AdVariantType
from core.apps.api.serializers.common.color import ListColorSerializer
from core.apps.api.serializers.common.size import ListSizeSerializer


class AdOptionSerializer(serializers.ModelSerializer):
    class Meta:
        model = AdOptionModel
        fields = ["id", "name", "value"]
        read_only_fields = ["id"]


class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = CategoryModel
        fields = ["id", "name"]
        read_only_fields = ["id"]


class AdImageSerializer(serializers.ModelSerializer):
    class Meta:
        model = AdImageModel
        fields = ["id", "image", "ad_variant", "is_primary", "order"]
        read_only_fields = ["id"]

    def to_representation(self, instance):
        data = super().to_representation(instance)
        if not instance.ad_variant:
            data.pop("ad_variant", None)
        return data


class AdVariantSerializer(serializers.ModelSerializer):
    color = ListColorSerializer()
    size = ListSizeSerializer()

    class Meta:
        model = AdVariantModel
        fields = ["id", "size", "color", "is_available", "price", "stock_quantity"]
        read_only_fields = ["id", "color_name"]


class AdListSerializer(serializers.ModelSerializer):
    is_liked = serializers.SerializerMethodField()
    rating = serializers.SerializerMethodField()
    reviews_count = serializers.SerializerMethodField()

    class Meta:
        model = AdModel
        fields = ["id", "name", "price", "image", "discount", "is_liked", "rating", "reviews_count", "is_available"]
        read_only_fields = fields

    def get_rating(self, obj):
        """Get average rating from feedbacks"""
        avg = obj.feedbacks.aggregate(avg=Avg("star"))["avg"]
        return round(avg, 1) if avg else 0

    def get_reviews_count(self, obj):
        """Get total count of feedbacks"""
        return obj.feedbacks.count()

    def get_is_liked(self, obj):
        """Check if current user liked this ad"""
        request = self.context.get("request")
        if not request or not request.user.is_authenticated:
            return False
        return UserLike.objects.filter(user=request.user, ad=obj).exists()


class AdDetailSerializer(AdListSerializer):
    variants = AdVariantSerializer(many=True, read_only=True)
    images = AdImageSerializer(many=True, read_only=True)
    colors = serializers.SerializerMethodField()
    sizes = serializers.SerializerMethodField()
    creator = serializers.SerializerMethodField()
    options = AdOptionSerializer(many=True, read_only=True)
    category = CategorySerializer(read_only=True)

    class Meta(AdListSerializer.Meta):
        fields = AdListSerializer.Meta.fields + [
            "description",
            "images",
            "variants",
            "colors",
            "sizes",
            "creator",
            "options",
            "category",
            "ad_type",
            "physical_product",
        ]

    def get_colors(self, obj):
        """Get unique colors from variants"""
        return list(obj.variants.values_list("color", flat=True).distinct())

    def get_sizes(self, obj):
        """Get unique sizes from variants"""
        return list(obj.variants.values_list("size", flat=True).distinct())

    def get_creator(self, obj):
        """Get creator information"""
        user = obj.user
        request = self.context.get("request")

        avatar_url = None
        if user.avatar and request:
            avatar_url = request.build_absolute_uri(user.avatar.url)

        if user.account_type == AccountType.BUSINESS:
            username = user.business.name if hasattr(user, "business") else user.username
        else:
            username = f"{user.first_name} {user.last_name}".strip() or user.username

        return {
            "id": user.id,
            "username": username,
            "avatar": avatar_url,
            "account_type": user.account_type,
            "joined_at": user.date_joined,
        }


class AdCreateSerializer(serializers.ModelSerializer):
    class Meta:
        model = AdModel
        fields = [
            "name",
            "ad_type",
            "category",
            "ad_category_type",
            "discount",
            "is_available",
            "physical_product",
            "plan",
            "tags",
            "image",
            "description",
        ]

    def create(self, validated_data):
        validated_data["user"] = self.context["request"].user
        return super().create(validated_data)