from sqlalchemy.exc import SQLAlchemyError

from models import Todo


class FakeScalarResult:
    def __init__(self, todos: list[Todo]) -> None:
        self.todos = todos

    def all(self) -> list[Todo]:
        return self.todos


class FakeSession:
    def __init__(self) -> None:
        self.todo_to_return: Todo | None = None
        self.added_todo: Todo | None = None
        self.committed = False
        self.deleted_todo: Todo | None = None
        self.should_fail_commit = False
        self.rolled_back = False
        self.todos_to_return: list[Todo] = []

    def add(self, todo: Todo) -> None:
        self.added_todo = todo
        todo.id = 1
        todo.completion = False

    def commit(self) -> None:
        if self.should_fail_commit:
            raise SQLAlchemyError("simulated commit failure")

        self.committed = True

    def get(
        self,
        _model: type[Todo],
        _todo_id: int,
    ) -> Todo | None:
        return self.todo_to_return

    def delete(self, todo: Todo) -> None:
        self.deleted_todo = todo

    def rollback(self) -> None:
        self.rolled_back = True

    def scalars(self, _statement: object) -> FakeScalarResult:
        return FakeScalarResult(self.todos_to_return)