#! /usr/bin/env python
#    Copyright 2012 Paul Munday
#    PO Box 28228, Portland, OR, USA 97228
#    paul at gatheringstorms.org

#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.

#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.

#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#    or <http://www.gatheringstorms.org/code/gpl.txt>.


import os.path
import sys
import urllib
import StringIO
import xml.etree.ElementTree as ET
import time

appID = "8D8D196B90DA0E177306D3CE8";

def get_stopID():
	
	'''Returns the Stop ID, first checking the command line, then the
	for the presence of a .stopID file in the users home directory,
	finally prompting for a stop ID'''
	
	home = os.path.expanduser("~")
	id_file = home + '/' +'.stopid'
	
	if (len(sys.argv) > 1):
		stopID = sys.argv[1]
	
	elif os.path.isfile(id_file):
		with open(id_file, 'r') as f:
			firstline = f.readline()
			stopID = firstline.rstrip()
	# TODO implement method to derive stop ID from text alias 
	
	else:
		stopID = raw_input ('please enter a stop ID number ')
	return stopID

def get_arrivals_info (stop_id, app_id):
	
	'''Queries Trimet for xml derived from Stop ID
	and returns it as a string'''
	
	arrivals_url = 'http://developer.trimet.org/ws/V1/arrivals/locIDs/' + stop_id + '/appID/' + app_id
	try:
		arrivals_data = urllib.urlopen(arrivals_url).read()
	except IOError:
		print 'Unable to make network connection!'
		sys.exit(2)
	if len(arrivals_data) == 0:
		print 'Arrival info was blank!'
		sys.exit(2)
	return arrivals_data

def conv_time (time_in):
	'''converts from milliseconds, returns formatted local time'''
	time_out = time.strftime("%I:%M %p",(time.localtime(time_in / 1000)))
	return time_out

# MAIN
stopID = get_stopID()
arrivals_info = get_arrivals_info(stopID,appID)

arrivals_tree = ET.parse(StringIO.StringIO(arrivals_info))
prefix = '{urn:trimet:arrivals}'
fp= './/' + prefix

# set human readable location, which direction bus is heading
for node in arrivals_tree.findall(fp + 'location'):
	if node.attrib['locid'] == stopID:
		stop_location =  node.attrib['desc']
		stop_direction =  node.attrib['dir']
# print arrivals info
try:
	print 'The next arrivals due at ' + stop_location + ' (Stop ID ' + stopID+ ') are:'
except NameError:
	print 'Invalid Stop ID!'
	sys.exit(3)
isabus = None	
for node in arrivals_tree.findall(fp + 'arrival'):
	print node.attrib['fullSign'] + ', ' + stop_direction
	if node.attrib['status'] == 'estimated':
		print 'Estimated arrival time: ' + conv_time(int(node.attrib['estimated']))	
		isabus = 'true' 
	elif node.attrib['status'] == 'scheduled':
		print 'Scheduled arrival time: ' + conv_time(int(node.attrib['scheduled']))
		isabus = 'true'
	elif node.attrib['status'] == 'delayed':
		print "This vehicle is delayed, arrival time is uncertain"
		isabus = 'true'
	elif node.attrib['status'] == 'cancelled':
		print 'This service has been cancelled'
		isabus = 'true'

	# warn if detour	
	if node.attrib['detour'] == 'true':
		print 'detours are in operation on this route'

# report on route status/inclement weather effects
for node in arrivals_tree.findall(fp + 'routeStatus'):
	print 'Route ' + node.attrib['route']
	if node.attrib['status'] == 'estimatedOnly':
		print 'Arrivals are only being reported if they can be estimated in the next hour due to inclement weather conditions'
	elif node.attrib['status'] == 'off':
		print "No arrivals are being reported for this route because conditions such as snow and ice make prediction impossible. Hope you don't get too cold. Snowpocalypse strikes again!"
	

# found stop but not a bus
if not isabus:
	print 'Oops! There does not appear to be a bus scheduled at this stop any time soon, you might consider walking.'