"""Equipment serializers."""

from drf_spectacular.utils import extend_schema_field
from rest_framework import serializers

from procurement.models import Equipment
from procurement.services import InventoryNumberGenerator

from ..equipment_policy import (
    EquipmentCreationPolicy,
    EquipmentPolicyValidationError,
    validate_responsible_department,
)


class EquipmentListSerializer(serializers.ModelSerializer):
    """Сериализатор для списка оборудования."""

    category_name = serializers.CharField(source="category.name", read_only=True)
    category_icon = serializers.CharField(
        source="category.icon", read_only=True, default="bi-box-seam"
    )
    department_name = serializers.CharField(source="department.name", read_only=True)
    responsible_name = serializers.CharField(
        source="responsible_person.get_full_name", read_only=True
    )
    status_display = serializers.CharField(source="get_status_display", read_only=True)
    is_under_warranty = serializers.BooleanField(read_only=True)
    comments_count = serializers.IntegerField(read_only=True, default=0)

    class Meta:
        model = Equipment
        fields = [
            "id",
            "name",
            "inventory_number",
            "serial_number",
            "category",
            "category_name",
            "category_icon",
            "status",
            "status_display",
            "department",
            "department_name",
            "responsible_person",
            "responsible_name",
            "location",
            "purchase_date",
            "purchase_cost",
            "notes",
            "is_under_warranty",
            "comments_count",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "inventory_number",
            "category_name",
            "category_icon",
            "department_name",
            "responsible_name",
            "status_display",
            "is_under_warranty",
            "comments_count",
            "created_at",
            "updated_at",
        ]

    def create(self, validated_data):
        """Автоматическая генерация инвентарного номера при создании."""
        validated_data["inventory_number"] = InventoryNumberGenerator.generate()
        return super().create(validated_data)

    def validate(self, attrs):
        """Validate department access and responsible-person consistency."""
        request = self.context.get("request")
        user = request.user if request else None

        try:
            if self.instance is None:
                responsible = attrs.get("responsible_person")
                if responsible is not None and not responsible.is_active:
                    raise EquipmentPolicyValidationError(
                        {
                            "responsible_person": (
                                "Ответственным может быть только активный сотрудник."
                            )
                        }
                    )
                return EquipmentCreationPolicy.resolve(user).validate_create(attrs)

            department = attrs.get("department", self.instance.department)
            responsible = attrs.get(
                "responsible_person",
                self.instance.responsible_person,
            )
            responsible_changed = (
                "responsible_person" in attrs
                and getattr(responsible, "id", None)
                != self.instance.responsible_person_id
            )
            department_changed = (
                "department" in attrs and department.id != self.instance.department_id
            )
            if (
                responsible_changed
                and responsible is not None
                and not responsible.is_active
            ):
                raise EquipmentPolicyValidationError(
                    {
                        "responsible_person": (
                            "Ответственным может быть только активный сотрудник."
                        )
                    }
                )
            if (
                responsible is not None
                and responsible.is_active
                and (responsible_changed or department_changed)
            ):
                validate_responsible_department(
                    department=department,
                    responsible=responsible,
                )
            return attrs
        except EquipmentPolicyValidationError as exc:
            raise serializers.ValidationError(exc.errors) from exc


class EquipmentDetailSerializer(serializers.ModelSerializer):
    """Сериализатор для детальной информации об оборудовании."""

    category_name = serializers.CharField(source="category.name", read_only=True)
    department_name = serializers.CharField(source="department.name", read_only=True)
    responsible_name = serializers.CharField(
        source="responsible_person.get_full_name", read_only=True
    )
    status_display = serializers.CharField(source="get_status_display", read_only=True)
    is_under_warranty = serializers.BooleanField(read_only=True)
    maintenance_count = serializers.SerializerMethodField()

    class Meta:
        model = Equipment
        fields = [
            "id",
            "name",
            "inventory_number",
            "serial_number",
            "category",
            "category_name",
            "status",
            "status_display",
            "department",
            "department_name",
            "responsible_person",
            "responsible_name",
            "location",
            "purchase_date",
            "warranty_until",
            "is_under_warranty",
            "purchase_cost",
            "notes",
            "maintenance_count",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "created_at",
            "updated_at",
            "is_under_warranty",
            "maintenance_count",
        ]

    @extend_schema_field(serializers.IntegerField())
    def get_maintenance_count(self, obj):
        """Количество записей обслуживания."""
        return obj.maintenance_history.count()