import pytest
from fastapi.testclient import TestClient
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from main import app, get_db
from models import Base

TEST_DB = "sqlite:///./test.db"
test_engine = create_engine(TEST_DB, connect_args={"check_same_thread": False})
TestSession = sessionmaker(autocommit=False, autoflush=False, bind=test_engine)
Base.metadata.create_all(bind=test_engine)

def override_get_db():
    db = TestSession()
    try:
        yield db
    finally:
        db.close()

app.dependency_overrides[get_db] = override_get_db
client = TestClient(app)

def test_create_todo():
    response = client.post('/todos/', json={"title": "Test title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"})
    assert response.status_code == 201
    data = response.json()
    assert "id" in data

def test_list_todos():
    client.post('/todos/', json={"title": "Test title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"})
    response = client.get('/todos/')
    assert response.status_code == 200
    assert len(response.json()) >= 1

def test_get_todo_by_id():
    created = client.post('/todos/', json={"title": "Test title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"}).json()
    item_id = created['id']
    response = client.get(f'/todos/{item_id}')
    assert response.status_code == 200
    assert response.json()['id'] == item_id

def test_get_todo_not_found():
    response = client.get('/todos/99999')
    assert response.status_code == 404

def test_update_todo():
    created = client.post('/todos/', json={"title": "Test title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"}).json()
    item_id = created['id']
    response = client.put(f'/todos/{item_id}', json={"title": "Updated title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"})
    assert response.status_code == 200

def test_delete_todo():
    created = client.post('/todos/', json={"title": "Test title", "description": "Test description", "due_date": "2024-01-15", "status": "pending"}).json()
    item_id = created['id']
    response = client.delete(f'/todos/{item_id}')
    assert response.status_code == 204
    response = client.get(f'/todos/{item_id}')
    assert response.status_code == 404