import time
import threading
import os
import subprocess
import sys


import pyperclip

def is_url_but_not_bitly(url):
    if url.startswith("https://www.youtube.com"):
        return True
    return False

def print_to_stdout(clipboard_content):
    print "     Yosh! Found an URL"
    tempstring = str(clipboard_content)
    pyperclip.copy('')
    print "     Launching youtube-dl to download"
    with open(os.devnull, "w") as fnull:
        subprocess.call("start youtube "+tempstring, stdout = fnull, stderr = fnull, shell = True)
    
class ClipboardWatcher(threading.Thread):
    def __init__(self, predicate, callback, pause=5.):
        super(ClipboardWatcher, self).__init__()
        self._predicate = predicate
        self._callback = callback
        self._pause = 5
        self._stopping = False

    def run(self):       
        recent_value = ""
        while not self._stopping:
            tmp_value = pyperclip.paste()
            if tmp_value != recent_value:
                recent_value = tmp_value
                if self._predicate(recent_value):
                    self._callback(recent_value)
            time.sleep(self._pause)

    def stop(self):
        self._stopping = True

def main():
    watcher = ClipboardWatcher(is_url_but_not_bitly, 
                               print_to_stdout,
                               5.)
    watcher.start()
    while True:
        try:
            print "Waiting for a youtube URL..."
            time.sleep(10)
        except KeyboardInterrupt:
            watcher.stop()
            break


if __name__ == "__main__":
    main()