from sqlalchemy import event, text

from app.auth.services import create_user
from app.extensions import db as database
from app.tasks.models import Task
from app.tasks.services import paginate_tasks


def seed_tasks(user_id: int, count: int) -> None:
    database.session.add_all(
        [
            Task(
                user_id=user_id,
                title=f"Paginated task {number:03d}",
                status="not_started",
                priority="normal",
            )
            for number in range(count)
        ]
    )
    database.session.commit()


def login(client, email: str) -> None:
    client.post(
        "/auth/login",
        data={"email": email, "password": "secure password"},
    )


def test_task_list_paginates_at_fifty_items(client, db):
    user = create_user("page_user", "page@example.com", "secure password")
    seed_tasks(user.id, 55)
    login(client, user.email)

    first = client.get("/tasks/")
    second = client.get("/tasks/?page=2")

    assert first.data.count(b'class="task-card ') == 50
    assert b"Page 1 of 2" in first.data
    assert second.data.count(b'class="task-card ') == 5
    assert b"Page 2 of 2" in second.data
    assert client.get("/tasks/?page=0").status_code == 400
    assert client.get("/tasks/?page=word").status_code == 400
    assert client.get("/tasks/?page=3").status_code == 404


def test_paginated_service_uses_bounded_query_count(app, db):
    user = create_user("query_user", "query@example.com", "secure password")
    seed_tasks(user.id, 55)
    user_id = user.id
    query_count = 0

    def count_query(*_args):
        nonlocal query_count
        query_count += 1

    event.listen(database.engine, "before_cursor_execute", count_query)
    try:
        page = paginate_tasks(user_id, page=1)
    finally:
        event.remove(database.engine, "before_cursor_execute", count_query)

    assert len(page.items) == 50
    assert page.total == 55
    assert query_count <= 3


def test_task_visibility_index_exists(db):
    indexes = database.session.execute(text("PRAGMA index_list('task')")).all()

    assert "ix_task_owner_visibility_status_due" in {row[1] for row in indexes}