from datetime import datetime, date
from typing import TYPE_CHECKING

from sqlalchemy import ForeignKey, Table, Column
from sqlalchemy.orm import Mapped, mapped_column, relationship

from models import BaseModel

if TYPE_CHECKING:
    from models import User


expenses_expense_tags = Table(
    'expenses_expense_tags',
    BaseModel.metadata,
    Column('expense_id', ForeignKey('expenses.id', ondelete='CASCADE'), primary_key=True),
    Column('expense_tag_id', ForeignKey('expense_tags.id'), primary_key=True),
)


class Expense(BaseModel):
    __tablename__ = 'expenses'

    id: Mapped[int] = mapped_column(primary_key=True)
    created_at: Mapped[datetime] = mapped_column(nullable=False)
    spent_date: Mapped[date] = mapped_column(nullable=False)
    name: Mapped[str] = mapped_column()
    comment: Mapped[str] = mapped_column()
    amount: Mapped[float] = mapped_column()

    created_by_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), nullable=False)
    created_by_user: Mapped["User"] = relationship(foreign_keys=[created_by_user_id], lazy="selectin")

    tags: Mapped[list["ExpenseTag"]] = relationship(
        secondary=expenses_expense_tags,
        lazy='selectin',
        back_populates='expenses',
        cascade='all, delete',
    )


class ExpenseTag(BaseModel):
    __tablename__ = 'expense_tags'
    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(unique=True)

    expenses: Mapped[list["Expense"]] = relationship(
        secondary=expenses_expense_tags,
        lazy='selectin',
        back_populates='tags',
    )