import pytest
from pymongo import MongoClient
from pymongo.errors import ConnectionFailure  # Import ConnectionFailure
from datetime import datetime
from bson.objectid import ObjectId
from pyxr.app import app

@pytest.fixture
def client():
    app.config['TESTING'] = True
    with app.test_client() as client:
        yield client

@pytest.fixture
def mongo_client():
    # 使用测试数据库
    client = MongoClient('localhost', 27017)
    db = client.test_flask_db
    todos = db.todos
    yield todos
    # 清理测试数据
    todos.delete_many({})
    client.close()

def test_get_todos_empty(client, mongo_client):
    # 测试空数据库情况
    response = client.get('/api/todos')
    assert response.status_code == 200
    assert response.json == []

def test_create_todo(client, mongo_client):
    # 测试创建待办事项
    test_todo = {
        'content': '测试待办事项',
        'degree': 1
    }
    response = client.post('/api/todos', json=test_todo)
    assert response.status_code == 201
    assert '_id' in response.json
    
    # 验证数据是否正确保存
    saved_todo = mongo_client.find_one({'_id': ObjectId(response.json['_id'])})
    assert saved_todo is not None
    assert saved_todo['content'] == test_todo['content']
    assert saved_todo['degree'] == test_todo['degree']
    assert 'timestamp' in saved_todo

def test_delete_todo(client, mongo_client):
    # 先创建一个待办事项
    todo = {
        'content': '要删除的待办事项',
        'degree': 1,
        'timestamp': datetime.now()
    }
    result = mongo_client.insert_one(todo)
    todo_id = str(result.inserted_id)
    
    # 测试删除
    response = client.delete(f'/api/todos/{todo_id}')
    assert response.status_code == 204
    
    # 验证是否已删除
    assert mongo_client.find_one({'_id': ObjectId(todo_id)}) is None

def test_delete_nonexistent_todo(client):
    # 测试删除不存在的待办事项
    fake_id = str(ObjectId())
    response = client.delete(f'/api/todos/{fake_id}')
    assert response.status_code == 204  # 即使不存在也返回204