import sys
import os
import subprocess
import importlib.util
import time
import threading


# --- 关键修正：依赖包检查与安装 ---
def check_and_install_packages(packages):
    """检查并安装所有必需的Python库。"""
    print("===== 依赖检查 =====")
    for package_name in packages:
        if importlib.util.find_spec(package_name) is None:
            print(f"⚠️ 未找到库: '{package_name}'，正在尝试自动安装...")
            try:
                subprocess.check_call([sys.executable, "-m", "pip", "install", package_name])
                print(f"✅ 成功安装 '{package_name}'")
            except subprocess.CalledProcessError:
                print(f"❌ 安装 '{package_name}' 失败。请手动运行 'pip install {package_name}' 后再试。")
                sys.exit(1)
        else:
            print(f"✔️ 库 '{package_name}' 已安装。")
    print("===== 依赖检查完成 =====\n")

# --- 配置 ---
REQUIRED_PACKAGES = ["requests","uvicorn[standard]"]
TXT_URL = os.environ.get('TXT_URL', "")
LOCAL_CODE_FILE = "api.py"  # 根据您的日志更新了文件名
PORT = 7860  # 根据您的日志更新了端口号
CHECK_INTERVAL = 20

# --- 全局变量 ---
current_code_identifier = None
stop_event = threading.Event()

def update_local_code_file():
    """检查远程代码更新。如果有更新，则下载并覆盖本地文件。"""
    global current_code_identifier
    # 为了简洁，这里省略了函数的内部代码，它和上一版完全相同
    print(f"[{time.strftime('%Y-%m-%d %H:%M:%S', time.localtime())}] 正在检查代码更新...")
    try:
        headers = {}
        if current_code_identifier and current_code_identifier.startswith('"'):
            headers['If-None-Match'] = current_code_identifier
        response = requests.get(TXT_URL, headers=headers, timeout=10)
        if response.status_code == 304:
            print("代码无变化。")
            return False
        response.raise_for_status()
        new_code_content = response.text
        new_etag = response.headers.get('ETag')
        new_identifier = new_etag if new_etag else hash(new_code_content)
        if new_identifier != current_code_identifier:
            print("检测到代码更新！正在更新本地文件...")
            with open(LOCAL_CODE_FILE, "w", encoding="utf-8") as f:
                f.write(new_code_content)
            current_code_identifier = new_identifier
            print(f"本地文件 '{LOCAL_CODE_FILE}' 已更新。Uvicorn 将自动重载。")
            return True
        else:
            print("代码无变化。")
            return False
    except requests.exceptions.RequestException as e:
        print(f"检查更新失败: {e}")
        return False

def monitor_in_background():
    """在后台线程中运行的监视器循环。"""
    while not stop_event.is_set():
        update_local_code_file()
        stop_event.wait(CHECK_INTERVAL)

if __name__ == "__main__":
    # 0. 首先，检查并安装所有依赖！
    check_and_install_packages(REQUIRED_PACKAGES)
    
    # 动态导入 requests 模块，因为它现在才确认被安装
    import requests

    # 1. 首次运行：必须先下载一次代码
    print("首次启动，正在下载初始代码...")
    update_local_code_file()
    if not os.path.exists(LOCAL_CODE_FILE):
        print(f"初始代码下载失败或内容为空，无法启动服务器。请检查URL: {TXT_URL}")
        sys.exit(1)

    # 2. 启动后台线程来监控未来的更新
    monitor_thread = threading.Thread(target=monitor_in_background)
    monitor_thread.daemon = True
    monitor_thread.start()
    print("后台更新监视器已启动。")

    # 3. 在主线程中启动 Uvicorn
    module_name = LOCAL_CODE_FILE.replace('.py', '')
    command = [
        sys.executable, "-m", "uvicorn",
        f"{module_name}:app",
        "--host", "0.0.0.0",
        "--port", str(PORT),
        "--reload"
    ]
    
    uvicorn_process = None
    try:
        print(f"正在启动 Uvicorn (reload模式)... 命令: {' '.join(command)}")
        uvicorn_process = subprocess.Popen(command)
        uvicorn_process.wait()
    except KeyboardInterrupt:
        print("\n检测到手动中断 (Ctrl+C)...")
    except Exception as e:
        print(f"\n启动Uvicorn时发生错误: {e}")
    finally:
        print("正在关闭后台监视器和Uvicorn...")
        stop_event.set()
        if uvicorn_process:
            uvicorn_process.terminate()
        print("程序已退出。")