from __future__ import annotations

from typing import Generic, TypeVar

from sqlalchemy import Select, func, or_, select
from sqlalchemy.orm import Session

ModelT = TypeVar("ModelT")


class Repository(Generic[ModelT]):
    model: type[ModelT]

    def __init__(self, session: Session) -> None:
        self.session = session

    def get(self, item_id: str) -> ModelT | None:
        return self.session.get(self.model, item_id)

    search_columns: tuple[str, ...] = ()

    def _search_statement(self, search: str | None = None) -> Select[tuple[ModelT]]:
        statement: Select[tuple[ModelT]] = select(self.model)
        if search and self.search_columns:
            term = f"%{search.strip()}%"
            filters = [getattr(self.model, column).ilike(term) for column in self.search_columns]
            statement = statement.where(or_(*filters))
        return statement

    def list(self, limit: int = 20, offset: int = 0, search: str | None = None) -> list[ModelT]:
        statement = self._search_statement(search).offset(offset).limit(limit)
        return list(self.session.scalars(statement))

    def count(self, search: str | None = None) -> int:
        subquery = self._search_statement(search).subquery()
        return self.session.scalar(select(func.count()).select_from(subquery)) or 0

    def add(self, item: ModelT) -> ModelT:
        self.session.add(item)
        self.session.flush()
        return item

    def delete(self, item: ModelT) -> None:
        self.session.delete(item)
        self.session.flush()