from rest_framework import serializers

from .models import CreditAccount, CreditLedger, CreditReservation, QuotaPolicy


class CreditAccountSerializer(serializers.ModelSerializer):
    class Meta:
        model = CreditAccount
        fields = ["id", "balance", "reserved_balance", "currency", "updated_at"]
        read_only_fields = fields


class CreditLedgerSerializer(serializers.ModelSerializer):
    # 成员展示名:优先真实姓名 → 用户名 → 邮箱;系统流水(无 user)留空
    user_label = serializers.SerializerMethodField()
    # 扣费项目:与任务监控类型列同源,供账户中心流水展示
    task_type = serializers.SerializerMethodField()
    project_title = serializers.SerializerMethodField()

    class Meta:
        model = CreditLedger
        fields = [
            "id",
            "user",
            "user_label",
            "project",
            "project_title",
            "task",
            "task_type",
            "ledger_type",
            "amount",
            "balance_after",
            "reason",
            "metadata",
            "created_at",
        ]
        read_only_fields = fields

    def get_user_label(self, obj):
        user = obj.user
        if user is None:
            return ""
        return user.first_name or user.username or user.email or ""

    def get_task_type(self, obj):
        task = getattr(obj, "task", None)
        return getattr(task, "task_type", "") or ""

    def get_project_title(self, obj):
        project = getattr(obj, "project", None)
        if project is None:
            return ""
        return getattr(project, "title", None) or getattr(project, "name", None) or ""


class CreditReservationSerializer(serializers.ModelSerializer):
    class Meta:
        model = CreditReservation
        fields = ["id", "user", "project", "task", "amount", "status", "expires_at", "created_at"]
        read_only_fields = fields


class QuotaPolicySerializer(serializers.ModelSerializer):
    class Meta:
        model = QuotaPolicy
        fields = ["id", "user", "project", "monthly_limit", "project_limit", "per_task_limit", "is_active"]
        read_only_fields = ["id"]