feat(api): make category and tags create or get

app/apps/api/fields/transactions.py

@@ -0,0 +1,69 @@
+from drf_spectacular.types import OpenApiTypes
+from drf_spectacular.utils import extend_schema_field
+from rest_framework import serializers
+
+from apps.transactions.models import TransactionCategory, TransactionTag
+
+
+@extend_schema_field(
+    {
+        "oneOf": [{"type": "string"}, {"type": "integer"}],
+        "description": "TransactionCategory ID or name. If the name doesn't exist, a new one will be created",
+    }
+)
+class TransactionCategoryField(serializers.Field):
+    def to_representation(self, value):
+        return {"id": value.id, "name": value.name}
+
+    def to_internal_value(self, data):
+        if isinstance(data, int):
+            try:
+                return TransactionCategory.objects.get(pk=data)
+            except TransactionCategory.DoesNotExist:
+                raise serializers.ValidationError(
+                    "Category with this ID does not exist."
+                )
+        elif isinstance(data, str):
+            category, created = TransactionCategory.objects.get_or_create(name=data)
+            return category
+        raise serializers.ValidationError(
+            "Invalid category data. Provide an ID or name."
+        )
+
+    @staticmethod
+    def get_schema():
+        return {
+            "type": "array",
+            "items": {"type": "string", "description": "TransactionTag ID or name"},
+        }
+
+
+@extend_schema_field(
+    {
+        "type": "array",
+        "items": {"oneOf": [{"type": "string"}, {"type": "integer"}]},
+        "description": "TransactionTag ID or name. If the name doesn't exist, a new one will be created",
+    }
+)
+class TransactionTagField(serializers.Field):
+    def to_representation(self, value):
+        return [{"id": tag.id, "name": tag.name} for tag in value.all()]
+
+    def to_internal_value(self, data):
+        tags = []
+        for item in data:
+            if isinstance(item, int):
+                try:
+                    tag = TransactionTag.objects.get(pk=item)
+                except TransactionTag.DoesNotExist:
+                    raise serializers.ValidationError(
+                        f"Tag with ID {item} does not exist."
+                    )
+            elif isinstance(item, str):
+                tag, created = TransactionTag.objects.get_or_create(name=item)
+            else:
+                raise serializers.ValidationError(
+                    "Invalid tag data. Provide an ID or name."
+                )
+            tags.append(tag)
+        return tags