import os
import subprocess
import sys
import time

from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer


def log(s):
 print('[Monitor] %s' % s)


class MyFileSystemEventHander(FileSystemEventHandler):

 def __init__(self, fn):
 super(MyFileSystemEventHander, self).__init__()
 self.restart = fn

 # 完成修改后启动
 def on_modified(self, event):
 if event.src_path.endswith('.py'):
 log('Python source file changed: %s' % event.src_path)
 self.restart()

process = None


def kill_process():
 global process
 if process:
 log('Kill process [%s]...' % process.pid)
 process.kill()
 process.wait()
 log('Process ended with code %s.' % process.returncode)
 process = None


def start_process():
 global process
 command = []
 # 加入Python 命令符
 command.append("python")
 appPath = os.path.abspath("./PythonWebApp/www/app.py")
 print(appPath)
 command.append(appPath)

 log('Start process command -> %s...' % ' '.join(command))
 process = subprocess.Popen(
 command, stdin=sys.stdin, stdout=sys.stdout, stderr=sys.stderr)


def restart_process():
 kill_process()
 start_process()


def start_watch(path, callback):

 # 监视目录文件
 observer = Observer()
 observer.schedule(MyFileSystemEventHander(
 restart_process), path, recursive=True)
 log('Watching directory %s...' % path)
 observer.start()

 # 开始执行入口文件
 start_process()
 try:
 while True:
 time.sleep(0.5)
 except KeyboardInterrupt:
 observer.stop()
 # 检测到键盘 ctrl C 终止命令后结束
 observer.join()


if __name__ == '__main__':
 print(os.path.abspath("."))
 # 在当前目录的子目录中进行监视
 path = os.path.abspath('./PythonWebApp/www/')
 print(os.path.exists(path))
 start_watch(path, None)