#!/usr/bin/python

import os, sys, time

if len(sys.argv) < 4:
    print "Usage: %s <title> <files to watch> <cmd>"%(sys.argv[0])
    sys.exit(1)

cmd = sys.argv[-1]
title = sys.argv[1]
watched_files = sys.argv[2:-1]

for file in watched_files:
    if not os.path.exists(file):
        raise RuntimeError, "The file %s must exist."%file

t = None
def update_timestamps():
    global t
    t = dict([(name,os.path.getctime(name)) for name in watched_files])

update_timestamps()

def run():
    print "\x1b]2;* (%s) Running %s\x07"%(title, cmd)
    print cmd
    t = time.time()
    if os.system(cmd):
        status = 'error'
    else:
        status = 'success'
    print "\x1b]2;(%s) %s (%.1fs)\x07"%(title, status, time.time()-t)


run()

def go():
    global t
    while True:
        try:
            for watch_file in watched_files:
                try:
                    t2 = os.path.getctime(watch_file)
                except:
                    continue
                if t2 != t[watch_file]:
                    update_timestamps()
                    print "%s changed"%watch_file
                    run()
                    break
        except OSError:
            pass
        time.sleep(1)

try:
    go()
except KeyboardInterrupt:
    print "Ctrl-C pressed; exiting watch."