from decimal import Decimal

from rest_framework import serializers

from apps.accounts.models import Team, TeamMember, User
from apps.ai.models import AITask, QualityWord
from apps.assets.models import Asset

# 成本异常阈值:实际成本 > 预估 × 此倍数(且预估 > 0)即标异常
COST_ANOMALY_RATIO = Decimal("1.5")


def is_cost_anomaly(estimated, actual) -> bool:
    est = estimated or Decimal("0")
    act = actual or Decimal("0")
    return bool(est > 0 and act > est * COST_ANOMALY_RATIO)


class QualityWordSerializer(serializers.ModelSerializer):
    class Meta:
        model = QualityWord
        fields = ["id", "stage", "slot", "text", "sort", "enabled", "created_at"]
        read_only_fields = ["id", "created_at"]


class AdminReviewAssetSerializer(serializers.ModelSerializer):
    """跨团队人像审核队列行:复用 AssetFileSerializer 的首图 preview_url。"""

    team_name = serializers.CharField(source="team.name", read_only=True, default=None)
    preview_url = serializers.SerializerMethodField()

    class Meta:
        model = Asset
        fields = ["id", "name", "category", "review_status", "review_error", "team", "team_name", "preview_url", "created_at"]
        read_only_fields = fields

    def get_preview_url(self, obj):
        from apps.assets.serializers import AssetFileSerializer

        # 用 prefetch 缓存(list(...))而非 .first():后者会另发查询,列表页 N+1 拖慢到数秒
        files = list(obj.files.all())
        return AssetFileSerializer(files[0]).data.get("preview_url", "") if files else ""


class AdminTeamSerializer(serializers.ModelSerializer):
    owner_username = serializers.CharField(source="owner.username", read_only=True, default=None)
    member_count = serializers.SerializerMethodField()
    balance = serializers.SerializerMethodField()

    class Meta:
        model = Team
        fields = ["id", "name", "status", "owner", "owner_username", "member_count", "balance", "created_at"]
        read_only_fields = fields

    def get_member_count(self, obj):
        anno = getattr(obj, "member_count_anno", None)
        return anno if anno is not None else obj.members.count()

    def get_balance(self, obj):
        acct = getattr(obj, "credit_account", None)
        return str(acct.balance) if acct is not None else "0"


class AdminTeamMemberSerializer(serializers.ModelSerializer):
    username = serializers.CharField(source="user.username", read_only=True)
    user_status = serializers.CharField(source="user.status", read_only=True)

    class Meta:
        model = TeamMember
        fields = ["id", "username", "role", "status", "user_status", "monthly_credit_limit"]
        read_only_fields = fields


class AdminUserSerializer(serializers.ModelSerializer):
    teams = serializers.SerializerMethodField()

    class Meta:
        model = User
        fields = ["id", "username", "status", "is_platform_admin", "date_joined", "teams"]
        read_only_fields = fields

    def get_teams(self, obj):
        return [
            {"team_id": str(m.team_id), "team_name": m.team.name, "role": m.role}
            for m in obj.team_memberships.select_related("team").all()
        ]


class AdminTaskSerializer(serializers.ModelSerializer):
    team_name = serializers.CharField(source="team.name", read_only=True, default=None)
    model_name = serializers.CharField(source="model_config.name", read_only=True, default=None)
    cost_anomaly = serializers.SerializerMethodField()

    class Meta:
        model = AITask
        fields = [
            "id", "task_type", "status", "team", "team_name", "model_name",
            "estimated_cost", "actual_cost", "cost_anomaly", "error_code", "created_at",
        ]
        read_only_fields = fields

    def get_cost_anomaly(self, obj) -> bool:
        return is_cost_anomaly(obj.estimated_cost, obj.actual_cost)


class AdminTaskDetailSerializer(AdminTaskSerializer):
    class Meta(AdminTaskSerializer.Meta):
        fields = AdminTaskSerializer.Meta.fields + [
            "project", "idempotency_key", "request_payload", "response_payload",
            "error_message", "submitted_at", "completed_at",
        ]
        read_only_fields = fields