WIP: initial fastapi endpoint implementation

Client endpoint - GET & POST implemented

backend/app/schemas/models.py

@@ -0,0 +1,100 @@
+"""
+This module contains Pydantic/Database Models that map database tables validate
+and serialize api responses.
+
+If the logic is identical -> SQLModel is used to do both.
+Otherwise pydantic - for api responses
+And SQLAlchemy is used for db data validation.
+
+TODO:
+Mapping & validation for:
+- Clients, Suppliers, Products, payments
+
+Done:
+* Table mappings
+"""
+from sqlmodel import SQLModel, Field, UniqueConstraint
+from datetime import datetime
+from sqlalchemy import Column, DateTime, func, Enum as SQLEnum
+from enum import Enum
+from typing import Optional
+
+
+class TradeType(str, Enum):
+    BUY = "Buy"
+    SELL = "Sell"
+
+
+class Client(SQLModel, table=True):
+    """Clients table mapping, api response validation and serialisation"""
+    id: Optional[int] = Field(default=None, primary_key=True)
+    tin_number: int = Field(nullable=False, unique=True)
+    names: str = Field(max_length=100, nullable=False)
+    phone_number: str = Field(max_length=10, nullable=False)
+
+
+class Supplier(SQLModel, table=True):
+    """Supplier table mapping, api response validation and serialisation"""
+    id: Optional[int] = Field(default=None, primary_key=True)
+    tin_number: int = Field(nullable=False, unique=True)
+    names: str = Field(max_length=100, nullable=False)
+    phone_number: str = Field(max_length=10, nullable=False)
+
+
+class Product(SQLModel, table=True):
+    """Products table mapping, api response validation and serialisation
+
+    NOTE: purchase price should update every time a supplier credits us goods
+        and price has changed
+    """
+    __table_args__ = (UniqueConstraint("product_code"),)
+
+    id: Optional[int] = Field(nullable=False, primary_key=True)
+    product_code: str = Field(max_length=10, nullable=False)
+    product_name: str = Field(max_length=20, nullable=False, unique=True)
+    purchase_price: int = Field(nullable=False)
+    date_modified: datetime = Field(
+        sa_column=Column(DateTime,
+                         server_default=func.now(),
+                         server_onupdate=func.now())
+    )
+
+
+class Payment(SQLModel, table=True):
+    """
+    Payments table mapping, api response validation and serialisation
+
+    Include both payments to suppliers and from clients
+    """
+    id: Optional[int] = Field(default=None, primary_key=True)
+    payment_type: TradeType = Field(
+        sa_column=Column(SQLEnum(TradeType), nullable=False)
+    )
+    product_code: str = Field(nullable=False, foreign_key="product.product_code")
+    client_id: Optional[int] = Field(nullable=False, foreign_key="client.id")
+
+    supplier_id: Optional[int] = Field(nullable=False, foreign_key="supplier.id")
+    amount: int = Field(nullable=False)
+    payment_method: str = Field(max_length=24, nullable=False)
+    date: datetime = Field(
+        sa_column=Column(DateTime, server_default=func.now())
+    )
+
+
+class Credit(SQLModel, table=True):
+    """Credit table mapping, api response validation and serialisation
+
+    Include both credit from suppliers and to clients
+    """
+    id: Optional[int] = Field(default=None, primary_key=True)
+    transcation_type: TradeType = Field(
+        sa_column=Column(SQLEnum(TradeType), nullable=False)
+    )
+    product_code: str = Field(nullable=False, foreign_key="product.product_code")
+    client_id: Optional[int] = Field(nullable=False, foreign_key="client.id")
+    supplier_id: Optional[int] = Field(nullable=False, foreign_key="supplier.id")
+    qty: int = Field(nullable=False)
+    amount: int = Field(nullable=False)
+    date: datetime = Field(
+        sa_column=Column(DateTime, server_default=func.now())
+    )