from django.contrib.auth import get_user_model
from rest_framework import serializers

from apps.accounts.models import ApiKey

User = get_user_model()


class PkAsIdMixin(serializers.Serializer):
    """Keep JSON `id` stable after ERD-named primary keys."""

    id = serializers.IntegerField(source="pk", read_only=True)


class UserSerializer(PkAsIdMixin, serializers.ModelSerializer):
    managed_by = serializers.PrimaryKeyRelatedField(
        queryset=User.objects.filter(status__in=["buh", "bu_admin"]),
        allow_null=True,
        required=False,
    )
    managed_by_name = serializers.CharField(
        source="managed_by.user_name", read_only=True, allow_null=True
    )
    managed_by_pending = serializers.PrimaryKeyRelatedField(read_only=True)
    managed_by_pending_name = serializers.CharField(
        source="managed_by_pending.user_name", read_only=True, allow_null=True
    )

    class Meta:
        model = User
        fields = [
            "id",
            "user_name",
            "status",
            "is_superuser",
            "managed_by",
            "managed_by_name",
            "managed_by_pending",
            "managed_by_pending_name",
            "managed_by_requested_at",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "is_superuser",
            "managed_by_name",
            "managed_by_pending",
            "managed_by_pending_name",
            "managed_by_requested_at",
            "created_at",
            "updated_at",
        ]


class UserWriteSerializer(PkAsIdMixin, serializers.ModelSerializer):
    """Create/update users for Account Admin. Password required on create."""

    password = serializers.CharField(write_only=True, required=False, allow_blank=False)
    managed_by = serializers.PrimaryKeyRelatedField(
        queryset=User.objects.filter(status__in=["buh", "bu_admin"]),
        allow_null=True,
        required=False,
    )
    managed_by_name = serializers.CharField(
        source="managed_by.user_name", read_only=True, allow_null=True
    )
    managed_by_pending = serializers.PrimaryKeyRelatedField(read_only=True)
    managed_by_pending_name = serializers.CharField(
        source="managed_by_pending.user_name", read_only=True, allow_null=True
    )

    class Meta:
        model = User
        fields = [
            "id",
            "user_name",
            "status",
            "is_superuser",
            "password",
            "managed_by",
            "managed_by_name",
            "managed_by_pending",
            "managed_by_pending_name",
            "managed_by_requested_at",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "is_superuser",
            "managed_by_name",
            "managed_by_pending",
            "managed_by_pending_name",
            "managed_by_requested_at",
            "created_at",
            "updated_at",
        ]

    def validate_password(self, value: str) -> str:
        if value is not None and not str(value).strip():
            raise serializers.ValidationError("Password cannot be blank.")
        return value

    def validate(self, attrs):
        if self.instance is None and not attrs.get("password"):
            raise serializers.ValidationError({"password": "This field is required."})

        new_status = attrs.get("status")
        if new_status == User.STATUS_SUPERUSER:
            raise serializers.ValidationError(
                {"status": "Superuser accounts cannot be created or assigned here."}
            )

        request = self.context.get("request")
        actor = getattr(request, "user", None) if request else None
        instance = self.instance
        if (
            instance is not None
            and actor is not None
            and getattr(actor, "is_authenticated", False)
            and instance.pk == actor.pk
            and "status" in attrs
            and attrs["status"] != instance.status
        ):
            if attrs["status"] == User.STATUS_INACTIVE:
                raise serializers.ValidationError(
                    {"status": "You cannot deactivate your own account."}
                )
            raise serializers.ValidationError(
                {"status": "You cannot change your own account status."}
            )
        return attrs

    def create(self, validated_data):
        password = validated_data.pop("password")
        user_name = validated_data.pop("user_name")
        return User.objects.create_user(
            user_name=user_name, password=password, **validated_data
        )

    def update(self, instance, validated_data):
        password = validated_data.pop("password", None)
        for attr, value in validated_data.items():
            setattr(instance, attr, value)
        if password:
            instance.set_password(password)
        instance.save()
        return instance


class SetPasswordSerializer(serializers.Serializer):
    password = serializers.CharField(write_only=True, allow_blank=False)

    def validate_password(self, value: str) -> str:
        if not str(value).strip():
            raise serializers.ValidationError("Password cannot be blank.")
        return value


class LoginSerializer(serializers.Serializer):
    user_name = serializers.CharField(max_length=30)
    password = serializers.CharField(write_only=True)


class ApiKeySerializer(serializers.ModelSerializer):
    class Meta:
        model = ApiKey
        fields = [
            "id",
            "name",
            "prefix",
            "is_active",
            "last_used_at",
            "created_at",
            "updated_at",
            "user",
        ]
        read_only_fields = fields


class ApiKeyCreateSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=100)
    user_id = serializers.IntegerField(required=False)