Corp/backend/api/v1/commerce/serializers.py

from rest_framework import serializers

from commerce.models import (
    Cost,
    Product,
    ProductBinding,
    Sale,
    SaleLine,
    SourceSystem,
    StockSnapshot,
)


class SourceSystemSerializer(serializers.ModelSerializer):
    class Meta:
        model = SourceSystem
        fields = [
            "id",
            "code",
            "name",
            "is_active",
            "metadata",
            "created_at",
            "updated_at",
        ]
        read_only_fields = ["id", "created_at", "updated_at"]


class ProductBindingSerializer(serializers.ModelSerializer):
    source_code = serializers.CharField(source="source.code", read_only=True)

    class Meta:
        model = ProductBinding
        fields = [
            "id",
            "product",
            "source",
            "source_code",
            "external_id",
            "external_sku",
            "is_primary",
            "created_at",
            "updated_at",
        ]
        read_only_fields = ["id", "created_at", "updated_at"]


class ProductSerializer(serializers.ModelSerializer):
    bindings = ProductBindingSerializer(many=True, read_only=True)
    variants_count = serializers.IntegerField(read_only=True)

    class Meta:
        model = Product
        fields = [
            "id",
            "parent",
            "kind",
            "sku",
            "name",
            "barcode",
            "description",
            "is_active",
            "variants_count",
            "bindings",
            "created_at",
            "updated_at",
        ]
        read_only_fields = ["id", "created_at", "updated_at"]


class SaleLineSerializer(serializers.ModelSerializer):
    net_amount = serializers.DecimalField(
        max_digits=18, decimal_places=2, read_only=True
    )

    class Meta:
        model = SaleLine
        fields = [
            "id",
            "sale",
            "product",
            "external_id",
            "external_product_id",
            "external_sku",
            "name",
            "quantity",
            "gross_amount",
            "discount_amount",
            "net_amount",
            "cost_amount",
            "metadata",
        ]

    def validate(self, attrs):
        gross = attrs.get("gross_amount", getattr(self.instance, "gross_amount", 0))
        discount = attrs.get(
            "discount_amount", getattr(self.instance, "discount_amount", 0)
        )
        if discount > gross:
            raise serializers.ValidationError(
                {"discount_amount": "Скидка не может превышать сумму позиции."}
            )
        return attrs


class SaleSerializer(serializers.ModelSerializer):
    source_code = serializers.CharField(source="source.code", read_only=True)
    lines = SaleLineSerializer(many=True, read_only=True)

    class Meta:
        model = Sale
        fields = [
            "id",
            "source",
            "source_code",
            "source_record",
            "external_id",
            "number",
            "event_type",
            "channel",
            "status",
            "counts_as_sale",
            "currency",
            "occurred_at",
            "source_updated_at",
            "lines",
            "created_at",
            "updated_at",
        ]


class CostSerializer(serializers.ModelSerializer):
    source_code = serializers.CharField(source="source.code", read_only=True)

    class Meta:
        model = Cost
        fields = [
            "id",
            "source",
            "source_code",
            "product",
            "sale_line",
            "external_id",
            "channel",
            "cost_type",
            "amount",
            "currency",
            "occurred_at",
            "metadata",
            "created_at",
        ]
        validators = []

    def validate(self, attrs):
        product = attrs.get("product", getattr(self.instance, "product", None))
        sale_line = attrs.get("sale_line", getattr(self.instance, "sale_line", None))
        if product is None and sale_line is None:
            raise serializers.ValidationError(
                "Нужно указать товар или позицию продажи."
            )
        external_id = attrs.get(
            "external_id", getattr(self.instance, "external_id", "")
        )
        if external_id:
            source = attrs.get("source", getattr(self.instance, "source", None))
            cost_type = attrs.get(
                "cost_type", getattr(self.instance, "cost_type", None)
            )
            duplicate = Cost.objects.filter(
                source=source,
                external_id=external_id,
                cost_type=cost_type,
            )
            if self.instance:
                duplicate = duplicate.exclude(pk=self.instance.pk)
            if duplicate.exists():
                raise serializers.ValidationError(
                    {"external_id": "Расход с таким внешним ID уже существует."}
                )
        return attrs


class StockSnapshotSerializer(serializers.ModelSerializer):
    source_code = serializers.CharField(source="source.code", read_only=True)
    available = serializers.DecimalField(
        max_digits=18, decimal_places=4, read_only=True
    )

    class Meta:
        model = StockSnapshot
        fields = [
            "id",
            "product",
            "source",
            "source_code",
            "warehouse_external_id",
            "warehouse_name",
            "quantity",
            "reserved",
            "available",
            "in_transit",
            "captured_at",
            "metadata",
            "created_at",
        ]


class ProductMetricsQuerySerializer(serializers.Serializer):
    date_from = serializers.DateTimeField(required=False)
    date_to = serializers.DateTimeField(required=False)

    def validate(self, attrs):
        if (
            attrs.get("date_from")
            and attrs.get("date_to")
            and attrs["date_from"] > attrs["date_to"]
        ):
            raise serializers.ValidationError(
                {"date_to": "Дата окончания должна быть не раньше даты начала."}
            )
        return attrs