"""Approval workflow serializers for procurement requests."""

from django.contrib.auth import get_user_model
from drf_spectacular.utils import extend_schema_field
from rest_framework import serializers

from procurement.constants import get_default_approval_step_name
from procurement.models import Approval, ApprovalRoute

from ...employees.serializers import DepartmentBriefSerializer, EmployeeBriefSerializer

User = get_user_model()


class ProcurementRequestCreateOptionsSerializer(serializers.Serializer):
    """Опции формы создания заявки на закупку."""

    processing_departments = DepartmentBriefSerializer(many=True)
    default_processing_department = serializers.IntegerField(allow_null=True)
    subscription_processing_departments = DepartmentBriefSerializer(many=True)
    subscription_default_processing_department = serializers.IntegerField(
        allow_null=True
    )


class ProcurementManualApprovalStepSerializer(serializers.Serializer):
    """Ручной этап согласования при отправке заявки."""

    priority = serializers.IntegerField(min_value=1)
    approver = serializers.PrimaryKeyRelatedField(
        queryset=User.objects.visible_in_ui().filter(is_active=True),
    )
    step_name = serializers.CharField(
        required=False,
        allow_blank=True,
        max_length=150,
    )

    def validate_priority(self, value):
        if not ApprovalRoute.objects.filter(priority=value).exists():
            raise serializers.ValidationError("Выберите настроенный этап согласования.")
        return value


class ProcurementManualApprovalStepsSerializer(serializers.Serializer):
    """Список ручных этапов согласования."""

    approval_steps = ProcurementManualApprovalStepSerializer(
        many=True,
        required=False,
        allow_empty=True,
    )

    def validate_approval_steps(self, value):
        priorities = [item["priority"] for item in value]
        duplicate_priorities = {
            priority for priority in priorities if priorities.count(priority) > 1
        }
        if duplicate_priorities:
            raise serializers.ValidationError(
                "Каждый этап согласования можно выбрать только один раз."
            )
        return value


class ApprovalSerializer(serializers.ModelSerializer):
    """Сериализатор для согласований."""

    approver = EmployeeBriefSerializer(read_only=True)
    approver_name = serializers.CharField(
        source="approver.get_full_name", read_only=True
    )
    status_display = serializers.CharField(source="get_status_display", read_only=True)
    step_label = serializers.SerializerMethodField()

    @extend_schema_field(serializers.CharField())
    def get_step_label(self, obj):
        return obj.step_name or get_default_approval_step_name(obj.priority)

    class Meta:
        model = Approval
        fields = [
            "id",
            "request",
            "approver",
            "approver_name",
            "priority",
            "step_name",
            "step_label",
            "status",
            "status_display",
            "comment",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "created_at",
            "updated_at",
            "approver_name",
            "step_name",
            "step_label",
            "status_display",
        ]