#!/usr/bin/env python
# Copyright 2006 John-Mark Gurney <gurney_j@resnet.uoregon.edu>
'''MPEG-TS Handling'''

__version__ = '$Change$'
# $Id$

default_audio_lang = 'eng'

import os
import sets

import sys
mpegtspath = '/Users/jgurney/p4/bktrau/info'
if mpegtspath not in sys.path:
	sys.path.append(mpegtspath)
import mpegts

from DIDLLite import StorageFolder, VideoItem, Resource
from FSStorage import FSObject, registerklassfun

from twisted.python import log, threadable
from twisted.spread import pb
from twisted.web import resource, server

class _LimitedFile(file):
	def __init__(self, *args, **kwargs):
		self.__size = kwargs['size']
		del kwargs['size']
		file.__init__(self, *args, **kwargs)

	def remain(self):
		pos = self.tell()
		if pos > self.__size:
			return 0
		return self.__size - pos

	def read(self, size=-1):
		if size < 0:
			return file.read(self, self.remain())

		return file.read(self, min(size, self.remain()))

def _gennameindexes(chan):
	ret = []
	d = {}

	for i in chan:
		t = '%s %s.%s' % (i['name'], i['major'], i['minor'])
		ret.append(t)
		d[t] = i

	return ret, d

class MPEGTSTransfer(pb.Viewable):
	def __init__(self, iterable, request):
		self.iter = iter(iterable)
		self.request = request
		request.registerProducer(self, 0)

	def resumeProducing(self):
		if not self.request:
			return
		# get data and write to request.
		try:
			data = self.iter.next()
			if data:
				# this .write will spin the reactor, calling
				# .doWrite and then .resumeProducing again, so
				# be prepared for a re-entrant call
				self.request.write(data)
		except StopIteration:
			if self.request:
				self.request.unregisterProducer()
				self.request.finish()
				self.request = None

	def pauseProducing(self):
		pass

	def stopProducing(self):
		# close zipfile
		self.request = None

	# Remotely relay producer interface.

	def view_resumeProducing(self, issuer):
		self.resumeProducing()

	def view_pauseProducing(self, issuer):
		self.pauseProducing()

	def view_stopProducing(self, issuer):
		self.stopProducing()

	synchronized = ['resumeProducing', 'stopProducing']

threadable.synchronize(MPEGTSTransfer)

class MPEGTSResource(resource.Resource):
	isLeaf = True

	def __init__(self, iter_):
		resource.Resource.__init__(self)

		self.iter = iter_

	def render(self, request):
		request.setHeader('content-type', 'video/mpeg')

		if request.method == 'HEAD':
			return ''

		# return data
		MPEGTSTransfer(self.iter, request)
		# and make sure the connection doesn't get closed
		return server.NOT_DONE_YET

class MPEGTS(FSObject, VideoItem):
	def __init__(self, *args, **kwargs):
		path = kwargs['path']
		del kwargs['path']
		self.tvct = kwargs['tvct']
		del kwargs['tvct']

		kwargs['content'] = MPEGTSResource(
		    mpegts.iteravpids(mpegts.TSPStream(open(path)),
		    sum(mpegts.getaudiovideopids(self.tvct['PMT']), [])))
		VideoItem.__init__(self, *args, **kwargs)
		FSObject.__init__(self, path)

		self.url = '%s/%s' % (self.cd.urlbase, self.id)
		self.res = Resource(self.url, 'http-get:*:video/mpeg:*')

	def doUpdate(self):
		pass

class MultiMPEGTS(FSObject, StorageFolder):
	def __init__(self, *args, **kwargs):
		path = kwargs['path']
		del kwargs['path']

		StorageFolder.__init__(self, *args, **kwargs)
		FSObject.__init__(self, path)

		# mapping from path to objectID
		self.pathObjmap = {}

	def doUpdate(self):
		f = mpegts.TSPStream(_LimitedFile(self.FSpath,
		    size= 2*1024*1024))
		self.tvct = mpegts.GetTVCT(f)

		doupdate = False
		origchildren, toindex = _gennameindexes(self.tvct['channels'])
		children = sets.Set(origchildren)
		for i in self.pathObjmap.keys():
			if i not in children:
				doupdate = True
				# delete
				self.cd.delItem(self.pathObjmap[i])
				del self.pathObjmap[i]

		for i in origchildren:
			if i in self.pathObjmap:
				continue

			# new object
			self.pathObjmap[i] = self.cd.addItem(self.id, MPEGTS,
			    i, path = self.FSpath, tvct = toindex[i])
			doupdate = True

		if doupdate:
			StorageFolder.doUpdate(self)

def detectmpegts(path, fobj):
	f = mpegts.TSPStream(_LimitedFile(path, size= 2*1024*1024))
	tvct = mpegts.GetTVCT(f)

	if len(tvct['channels']) == 1:
		return None, None
		# We might reenable this once we have pid filtering working
		# fast enough.
		#return MPEGTS, { 'path': path, 'tvct': tvct['channels'][0] }
	elif len(tvct['channels']) > 1:
		return MultiMPEGTS, { 'path': path }

	return None, None

registerklassfun(detectmpegts)