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

engine = create_engine("sqlite:///:memory:", connect_args={"check_same_thread": False})
TestSession = sessionmaker(bind=engine)
Base.metadata.create_all(bind=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 Todo", "description": "This is a test todo.", "due_date": "2023-12-31"})
    assert response.status_code == 201
    assert response.json()["title"] == "Test Todo"
    assert response.json()["status"] == "pending"

def test_read_todos():
    client.post("/todos", json={"title": "Todo 1", "description": "First todo.", "due_date": "2023-12-31"})
    client.post("/todos", json={"title": "Todo 2", "description": "Second todo.", "due_date": "2024-01-01"})
    response = client.get("/todos")
    assert response.status_code == 200
    assert len(response.json()) == 2

def test_read_todo():
    todo = client.post("/todos", json={"title": "Test Todo", "description": "This is a test todo.", "due_date": "2023-12-31"})
    response = client.get(f"/todos/{todo.json()['id']}")
    assert response.status_code == 200
    assert response.json()["title"] == "Test Todo"

def test_read_todo_not_found():
    response = client.get("/todos/999")
    assert response.status_code == 404

def test_update_todo():
    todo = client.post("/todos", json={"title": "Test Todo", "description": "This is a test todo.", "due_date": "2023-12-31"})
    response = client.put(f"/todos/{todo.json()['id']}", json={"title": "Updated Todo", "description": "Updated description.", "due_date": "2024-01-01", "status": "completed"})
    assert response.status_code == 200
    assert response.json()["title"] == "Updated Todo"
    assert response.json()["status"] == "completed"

def test_delete_todo():
    todo = client.post("/todos", json={"title": "Test Todo", "description": "This is a test todo.", "due_date": "2023-12-31"})
    response = client.delete(f"/todos/{todo.json()['id']}")
    assert response.status_code == 204
    response = client.get(f"/todos/{todo.json()['id']}")
    assert response.status_code == 404