"""
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(default=None, 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(
        default=None,
        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(
        default=None,
        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(
        default=None,
        sa_column=Column(DateTime, server_default=func.now())
    )