#!/usr/bin/python -tt

# Axia GPIO-controlled recording v1.0
# Copyright (c) 2008, John Morrissey <jwm@horde.net>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#	* Redistributions of source code must retain the above copyright notice,
#	  this list of conditions and the following disclaimer.
#	* Redistributions in binary form must reproduce the above copyright
#	  notice, this list of conditions and the following disclaimer in the
#	  documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

GPIO_NODE = 'gpio0.example.com'
GPIO_PORT = 93
GPO_CHANNEL = 1
STREAM_URL = 'http://streaming.example.com/stream'
DEST_DIR = '/output/path'

import os
import re
import sys
from syslog import *
from tempfile import mkstemp
from time import strftime

from twisted.internet import reactor, protocol
from twisted.protocols import basic
from twisted.web import client

STREAM_TRANSPORTS = []
STREAM_AUTORESTART = True

class StoppableHTTPPageDownloader(client.HTTPPageDownloader):
	def connectionMade(self):
		# Threads can race to access the stream_transport global, so keep a
		# list of transports and have everything that needs the transport
		# for the recently completed connection use the 0 index. This list
		# should never be more than two entries; if it is, something has
		# gone awry and old transports are not being properly reaped.
		globals()['STREAM_TRANSPORTS'].append(self.transport)
		return client.HTTPPageDownloader.connectionMade(self)

class StoppableHTTPDownloader(client.HTTPDownloader):
	protocol = StoppableHTTPPageDownloader

def stream_record_complete(result, filename):
	if result:
		syslog(LOG_INFO, 'Stream record to %s complete: %s' % (filename, str(result)))
	else:
		syslog(LOG_INFO, 'Stream record to %s complete.' % filename)

	if globals()['STREAM_AUTORESTART']:
		syslog(LOG_INFO,
			'Received stream end-of-file for %s, but recording still in progress. Resuming recording...' %
			filename)
		start_stream_download(STREAM_URL)

	completed_name = \
		re.sub(r'inprogress-(\d{4}-\w{3}-\d{2}-[\d:]{8})-.{6}.mp3', 
			r'complete-\1-%s.mp3' % strftime('%Y-%b-%d-%H:%M:%S').lower(),
			filename)
	syslog(LOG_DEBUG,
		'Renaming output file %s to %s.' % (filename, completed_name))
	os.rename(filename, completed_name)
	STREAM_AUTORESTART = True

def stream_record_failed(failure, filename):
	syslog(LOG_ERR, 'Stream record failed: %s' % str(failure))
	if globals()['STREAM_AUTORESTART']:
		syslog(LOG_ERR,
			'Error while recording stream to %s, attempting to resume recording: %s' %
			(filename, failure.getErrorMessage()))
		start_stream_download(STREAM_URL)
	STREAM_AUTORESTART = True

def start_stream_download(url):
	fd, name = mkstemp(dir=DEST_DIR, suffix='.mp3',
		prefix='inprogress-%s-' % strftime('%Y-%b-%d-%H:%M:%S').lower())
	os.close(fd)

	scheme, host, port, path = client._parse(url)
	factory = StoppableHTTPDownloader(url, name)
	factory.deferred.addCallback(
		stream_record_complete, name).addErrback(
		stream_record_failed, name)
	reactor.connectTCP(host, port, factory)
	return factory

class GpioClient(basic.LineReceiver):
	def connectionMade(self):
		syslog(LOG_INFO, 'Connected to GPIO node %s on port %d.' %
			(GPIO_NODE, GPIO_PORT))
		self.transport.write('ADD GPO\n')

	def lineReceived(self, data):
		global STREAM_TRANSPORTS, STREAM_AUTORESTART

		data = data.rstrip()
		syslog(LOG_DEBUG, 'Received GPIO trigger: %s' % data)
		if data.startswith('GPO %d l' % GPO_CHANNEL):
			# If we see pin #1 ("on" light) already low (triggered)
			# and we aren't recording, we must have missed the initial
			# trigger ("L"). Start recording.
			if not STREAM_TRANSPORTS:
				start_stream_download(STREAM_URL)
		elif data.startswith('GPO %d L' % GPO_CHANNEL):
			# If we see pin #1 ("on" light) go low (triggered),
			# stop any existing recording (we must have missed the
			# line going high) and start recording.
			if STREAM_TRANSPORTS:
				STREAM_AUTORESTART = False
				syslog(LOG_DEBUG, 'GPO L: closing stream connection.')
				STREAM_TRANSPORTS[0].loseConnection()
				del STREAM_TRANSPORTS[0]
			start_stream_download(STREAM_URL)
		elif re.match(r'^GPO %d [hH]' % GPO_CHANNEL, data):
			# Whenever we see pin #1 ("on" light) go high (released),
			# we want to stop recording, regardless of whether the
			# line is going high *right now* ("H") or went high previously
			# ("h"), since we might have missed the line's release ("H").
			if STREAM_TRANSPORTS:
				STREAM_AUTORESTART = False
				syslog(LOG_DEBUG, 'GPO [hH]: closing stream connection.')
				STREAM_TRANSPORTS[0].loseConnection()
				del STREAM_TRANSPORTS[0]

class GpioFactory(protocol.ReconnectingClientFactory):
	protocol = GpioClient

	def buildProtocol(self, addr):
		self.resetDelay()
		return self.protocol()

	def clientConnectionFailed(self, connector, reason):
		if reason.value.args:
			syslog(LOG_ERR,
				'GPIO connection failed; attempting reconnect: %s' %
				' '.join(reason.value.args))
		else:
			syslog(LOG_ERR, 'GPIO connection failed; attempting reconnect.')
		protocol.ReconnectingClientFactory.clientConnectionFailed(
			self, connector, reason)

	def clientConnectionLost(self, connector, reason):
		if reason.value.args:
			syslog(LOG_NOTICE,
				'GPIO connection lost; attempting reconnect: %s' %
				' '.join(reason.value.args))
		else:
			syslog(LOG_NOTICE, 'GPIO connection lost; attempting reconnect.')
		protocol.ReconnectingClientFactory.clientConnectionLost(
			self, connector, reason)

if __name__ == '__main__':
	openlog(os.path.basename(sys.argv[0]), LOG_PID)

	reactor.connectTCP(GPIO_NODE, GPIO_PORT, GpioFactory())
	reactor.run()