import os
import gevent
import time
import sys

path_to_read = './input'

def is_ignored(basename):
	'if basename in queue >= 10 sec + len(queue) then ignore'
	if 'ignored_dict' not in globals():
		global ignored_dict
		ignored_dict = {}
	if basename in ignored_dict:
		delta = ignored_dict[basename]['delta']
		if delta.next() >= 10+len(watchdir_list):
			return True
		else:
			return False
	else:
		ignored_dict.update({basename: {'delta': iter_delta()}})
		return False


def watchdog():
	'eventloop delete basename who in queue more than 5min'
	while True:
		if 'ignored_dict' in globals():
			if ignored_dict:
				for basename, iterator in ignored_dict.items():
					#delete all ignored (300sec)5min old
					if iterator['delta'].next() > 300:
						del ignored_dict[basename]
		gevent.sleep(5)
	raise SystemExit('watchdog')


def iter_delta():
	'return time delta as generator'
	timestamp = int((time.time() + 0.5))
	while True:
		current_timestamp = int((time.time() + 0.5))
		yield (current_timestamp - timestamp)


def watch_dir():
	'eventloop append basename in queue if not ignored'
	while True:
		if os.path.exists(path_to_read):
			if 'watchdir_list' not in globals():
				global watchdir_list
				watchdir_list = []
			for basename in os.listdir(path_to_read):
				if basename not in watchdir_list:
					if not is_ignored(basename):
						watchdir_list.append(basename)
		else:
			raise SystemExit('watch_dir')
		gevent.sleep(0.1)


def read_file():
	'eventloop read first basename from queue'
	while True:
		if 'watchdir_list' not in globals():
			break
		if watchdir_list:
			basename = watchdir_list[0]
			path = os.path.join(path_to_read, basename)
			if os.path.isfile(path):
				try:
					with open(path, 'r') as fd:
						data = fd.read()
					fd.close()
					print basename,'read ok'
					watchdir_list.remove(basename)
				except IOError as err:
					print basename,'read bad'
					watchdir_list.remove(basename)
			else:
				pass
		gevent.sleep(0.1)
	raise SystemExit('read_file')


def init():
	try:
		g_watch_dir = gevent.spawn(watch_dir)
		g_read_file = gevent.spawn(read_file)
		g_watchdog = gevent.spawn(watchdog)
		#
		g_watch_dir.join()
		g_read_file.join()
		g_watchdog.join()
	except KeyboardInterrupt as err:
		sys.exit(1)


init()