Add db & pydantic models + set up alembic

backend/app/alembic/README

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+Generic single-database configuration.

backend/app/alembic/env.py

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+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+import os
+from dotenv import load_dotenv
+from sqlmodel import SQLModel
+from app.models import Client, Supplier, Product, Payment, Credit
+
+load_dotenv()
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+target_metadata = SQLModel.metadata
+url = os.getenv("DATABASE_URL")
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        url=url,
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

backend/app/alembic/script.py.mako

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+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    ${downgrades if downgrades else "pass"}

backend/app/alembic/versions/5840d2b52dd8_rebuild.py

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+"""Rebuild
+
+Revision ID: 5840d2b52dd8
+Revises: 
+Create Date: 2025-06-01 14:27:25.657473
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+
+# revision identifiers, used by Alembic.
+revision: str = '5840d2b52dd8'
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('client',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('tin_number', sa.Integer(), nullable=False),
+    sa.Column('names', sqlmodel.sql.sqltypes.AutoString(length=100), nullable=False),
+    sa.Column('phone_number', sqlmodel.sql.sqltypes.AutoString(length=10), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('tin_number')
+    )
+    op.create_table('product',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('product_code', sqlmodel.sql.sqltypes.AutoString(length=10), nullable=False),
+    sa.Column('product_name', sqlmodel.sql.sqltypes.AutoString(length=20), nullable=False),
+    sa.Column('purchase_price', sa.Integer(), nullable=False),
+    sa.Column('date_modified', sa.DateTime(), server_default=sa.text('now()'), nullable=True),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('product_code'),
+    sa.UniqueConstraint('product_name')
+    )
+    op.create_table('supplier',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('tin_number', sa.Integer(), nullable=False),
+    sa.Column('names', sqlmodel.sql.sqltypes.AutoString(length=100), nullable=False),
+    sa.Column('phone_number', sqlmodel.sql.sqltypes.AutoString(length=10), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('tin_number')
+    )
+    op.create_table('credit',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('transcation_type', sa.Enum('BUY', 'SELL', name='tradetype'), nullable=False),
+    sa.Column('product_code', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('client_id', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('supplier_id', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('qty', sa.Integer(), nullable=False),
+    sa.Column('amount', sa.Integer(), nullable=False),
+    sa.Column('date', sa.DateTime(), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
+    sa.ForeignKeyConstraint(['product_code'], ['product.product_code'], ),
+    sa.ForeignKeyConstraint(['supplier_id'], ['supplier.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('payment',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('payment_type', sa.Enum('BUY', 'SELL', name='tradetype'), nullable=False),
+    sa.Column('product_code', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('client_id', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('supplier_id', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('amount', sa.Integer(), nullable=False),
+    sa.Column('payment_method', sqlmodel.sql.sqltypes.AutoString(length=24), nullable=False),
+    sa.Column('date', sa.DateTime(), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
+    sa.ForeignKeyConstraint(['product_code'], ['product.product_code'], ),
+    sa.ForeignKeyConstraint(['supplier_id'], ['supplier.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('payment')
+    op.drop_table('credit')
+    op.drop_table('supplier')
+    op.drop_table('product')
+    op.drop_table('client')
+    # ### end Alembic commands ###

backend/app/alembic/versions/bfb086d8d500_fix_client_id_in_credit_type_to_int.py

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+"""Fix client_id in Credit type to int
+
+Revision ID: bfb086d8d500
+Revises: 5840d2b52dd8
+Create Date: 2025-06-01 14:53:57.095181
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+# revision identifiers, used by Alembic.
+revision: str = 'bfb086d8d500'
+down_revision: Union[str, None] = '5840d2b52dd8'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('credit',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('transcation_type', sa.Enum('BUY', 'SELL', name='tradetype'), nullable=False),
+    sa.Column('product_code', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('client_id', sa.Integer(), nullable=False),
+    sa.Column('supplier_id', sa.Integer(), nullable=False),
+    sa.Column('qty', sa.Integer(), nullable=False),
+    sa.Column('amount', sa.Integer(), nullable=False),
+    sa.Column('date', sa.DateTime(), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
+    sa.ForeignKeyConstraint(['product_code'], ['product.product_code'], ),
+    sa.ForeignKeyConstraint(['supplier_id'], ['supplier.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('payment',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('payment_type', sa.Enum('BUY', 'SELL', name='tradetype'), nullable=False),
+    sa.Column('product_code', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('client_id', sa.Integer(), nullable=False),
+    sa.Column('supplier_id', sa.Integer(), nullable=False),
+    sa.Column('amount', sa.Integer(), nullable=False),
+    sa.Column('payment_method', sqlmodel.sql.sqltypes.AutoString(length=24), nullable=False),
+    sa.Column('date', sa.DateTime(), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
+    sa.ForeignKeyConstraint(['product_code'], ['product.product_code'], ),
+    sa.ForeignKeyConstraint(['supplier_id'], ['supplier.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('payment')
+    op.drop_table('credit')
+    # ### end Alembic commands ###

backend/app/api/api.py

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+"""
+API Home
+"""
+from fastapi import APIRouter
+
+
+api_router = APIRouter()

backend/app/config.py

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+import secrets
+import warnings
+from typing import Annotated, Any, Literal
+from pydantic import (
+    MySQLDsn
+)
+from pydantic_core import MultiHostUrl
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    """
+    """
+    model_config = SettingsConfigDict(
+        # One level above ./backend
+        env_file='../.env',
+        env_ignore_empty=True,
+        extra='ignore'
+    )
+    SECRET_KEY: str = secrets.token_urlsafe(32)
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 8 # 8 days
+
+    MYSQL_SERVER: str
+    MYSQL_PORT: int = 3306
+    MYSQL_USER: str
+    MYSQL_PASSWORD: str = ""
+    MYSQL_DB: str = ""
+
+    @computed_field # type: ignore[prop-decorator]
+    @property
+    def SQLALCHEMY_DATABASE_URI(self) -> MySQLDsn:
+        return MultiHostUrl.build(
+            scheme="mysql+mysqldb",
+            username=self.MYSQL_USER,
+            password=self.MYSQL_PASSWORD,
+            host=self.MYSQL_SERVER,
+            port=self.MYSQL_PORT,
+            path=self.MYSQL_DB
+        ) # type: ignore
+
+settings = Settings() # type: ignore

backend/app/crud/client.py

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+"""
+The Client table
+"""
+from fastapi import APIRouter, HTTPException
+from sqlmodel import func, select
+from app.models import Client, Supplier, Product, Payment, Credit
+from typing import Any
+
+router = APIRouter(prefix="/client", tags=["items"])
+
+
+@router.get("/", response_model=Client)
+def read_clients(
+    session: SessionDep,
+)

backend/app/crud/product.py

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+"""
+TODO: when Credit.purchase_price is updated, update Product.purchase_price
+"""

backend/app/db.py

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+from sqlmodel import Session, create_engine, select
+from app.config import settings
+from app.models import Client, Supplier
+
+engine = create_engine(str(settings.SQLALCHEMY_DATABASE_URI))
+
+
+def init_db(session: Session) -> None:
+    """"""

backend/app/main.py

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+#!/usr/bin/env python3
+"""Entry point for fastapi app 
+
+NOTE:
+- 
+"""
+from app.config import settings
+from typing import Union
+from fastapi import FastAPI
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json"
+)
+
+@app.get("/")
+def read_root():
+    """
+    """
+    return {"Hello": "World"}

backend/app/models.py

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+"""
+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())
+    )