Adding a common moneratary amount field type

api/app/account/models.py

@@ -1,8 +1,6 @@
-from typing import Optional, Any
+from typing import Optional
 
-from pydantic import computed_field
 from sqlmodel import Relationship
-from sqlalchemy.sql import text
 
 from account.enums import CategoryFamily, Asset, Liability, AccountFamily
 from account.schemas import AccountBaseId

api/app/account/schemas.py

@@ -3,11 +3,12 @@ from decimal import Decimal
 from typing import Optional
 from uuid import UUID, uuid4
 
-from pydantic.json_schema import SkipJsonSchema
 from sqlmodel import Field, SQLModel
 from pydantic import Field as PydField
+from pydantic.json_schema import SkipJsonSchema
 
 from account.enums import Asset, Liability, CategoryFamily
+from core.types import MonetaryAmount
 
 class AccountBase(SQLModel):
     name: str = Field(index=True)
@@ -39,7 +40,7 @@ class AccountWrite(BaseAccountWrite):
         }
     })
     opening_date: date = Field()
-    opening_balance: Decimal = Field(decimal_places=2, default=0)
+    opening_balance: MonetaryAmount = Field()
 
 class AccountCreate(AccountWrite):
     pass

api/app/core/types.py

@@ -0,0 +1,41 @@
+from dataclasses import dataclass
+from decimal import Decimal
+from typing import Any
+
+from pydantic import GetCoreSchemaHandler
+from pydantic_core import core_schema
+
+@dataclass
+class MonetaryAmount:
+    amount: Decimal# = Field(decimal_places=2, default=0)
+
+    @classmethod
+    def __get_pydantic_core_schema__(
+            cls, source: type[Any], handler: GetCoreSchemaHandler
+    ) -> core_schema.CoreSchema:
+        assert source is MonetaryAmount
+        return core_schema.no_info_after_validator_function(
+            cls._validate,
+            core_schema.float_schema(multiple_of=0.01),
+            serialization=core_schema.plain_serializer_function_ser_schema(
+                cls._serialize,
+                info_arg=False,
+                return_schema=core_schema.float_schema(multiple_of=0.01),
+            ),
+        )
+
+    @staticmethod
+    def _validate(value: str) -> 'CompressedString':
+        inverse_dictionary: dict[str, int] = {}
+        text: list[int] = []
+        for word in value.split(' '):
+            if word not in inverse_dictionary:
+                inverse_dictionary[word] = len(inverse_dictionary)
+            text.append(inverse_dictionary[word])
+        return MonetaryAmount(
+            {v: k for k, v in inverse_dictionary.items()}, text
+        )
+
+    @staticmethod
+    def _serialize(value: 'CompressedString') -> str:
+        return value.amount