#!/usr/bin/env python
# -*- Mode: Python -*-
# vi:si:et:sw=4:sts=4:ts=4

# discoverer.py
# (c) 2005 Edward Hervey <edward at fluendo dot com>
# Discovers multimedia information on files

# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# 
# This library 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
# Lesser General Public License for more details.
# 
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

"""
Class and functions for getting multimedia information about files
"""

import os.path

import pygtk
pygtk.require('2.0')
import gobject

import pygst
pygst.require('0.10')
import gst

from gst.extend.pygobject import gsignal

class Discoverer(gst.Pipeline):
    """
    Discovers information about files.
    This class is event-based and needs a mainloop to work properly.
    Emits the 'discovered' signal when discovery is finished.

    The 'discovered' callback has one boolean argument, which is True if the
    file contains decodable multimedia streams.
    """
    __gsignals__ = {
        'discovered' : (gobject.SIGNAL_RUN_FIRST,
                        None,
                        (gobject.TYPE_BOOLEAN, ))
        }
    
    mimetype = None

    audiocaps = {}
    videocaps = {}

    videowidth = 0
    videoheight = 0
    videorate = 0

    audiofloat = False
    audiorate = 0
    audiodepth = 0
    audiowidth = 0
    audiochannels = 0

    audiolength = 0L
    videolength = 0L

    is_video = False
    is_audio = False

    otherstreams = []

    finished = False
    tags = {}


    def __init__(self, filename):
        gobject.GObject.__init__(self)

        self.mimetype = None

        self.audiocaps = {}
        self.videocaps = {}

        self.videowidth = 0
        self.videoheight = 0
        self.videorate = gst.Fraction(0,1)

        self.audiofloat = False
        self.audiorate = 0
        self.audiodepth = 0
        self.audiowidth = 0
        self.audiochannels = 0

        self.audiolength = 0L
        self.videolength = 0L

        self.is_video = False
        self.is_audio = False

        self.otherstreams = []

        self.finished = False
        self.tags = {}
        self._success = False

        self._timeoutid = 0
        
        if not os.path.isfile(filename):
            self.finished = True
            return
        
        # the initial elements of the pipeline
        self.src = gst.element_factory_make("filesrc")
        self.src.set_property("location", filename)
        self.src.set_property("blocksize", 1000000)
        self.dbin = gst.element_factory_make("decodebin")
        self.add(self.src, self.dbin)
        self.src.link(self.dbin)
        self.typefind = self.dbin.get_by_name("typefind")

        # callbacks
        self.typefind.connect("have-type", self._have_type_cb)
        self.dbin.connect("new-decoded-pad", self._new_decoded_pad_cb)
        self.dbin.connect("unknown-type", self._unknown_type_cb)

    def _finished(self, success=False):
        self.debug("success:%d" % success)
        self._success = success
        self.bus.remove_signal_watch()
        if self._timeoutid:
            gobject.source_remove(self._timeoutid)
            self._timeoutid = 0
        gobject.idle_add(self._stop)
        return False

    def _stop(self):
        self.debug("success:%d" % self._success)
        self.finished = True
        self.set_state(gst.STATE_READY)
        self.debug("about to emit signal")
        self.emit('discovered', self._success)
        

    def _bus_message_cb(self, bus, message):
        if message.type == gst.MESSAGE_EOS:
            self._finished()
        elif message.type == gst.MESSAGE_TAG:
            for key in message.parse_tag().keys():
                self.tags[key] = message.structure[key]
        elif message.type == gst.MESSAGE_ERROR:
            self._finished()

    def discover(self):
        """Find the information on the given file asynchronously"""
        self.debug("starting discovery")
        if self.finished:
            self.emit('discovered', False)
            return

        self.bus = self.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect("message", self._bus_message_cb)

        # 3s timeout
        self._timeoutid = gobject.timeout_add(3000, self._finished)
        
        self.info("setting to PLAY")
        if not self.set_state(gst.STATE_PLAYING):
            self._finished()

    def _time_to_string(self, value):
        """
        transform a value in nanoseconds into a human-readable string
        """
        ms = value / gst.MSECOND
        sec = ms / 1000
        ms = ms % 1000
        min = sec / 60
        sec = sec % 60
        return "%2dm %2ds %3d" % (min, sec, ms)

    def print_info(self):
        """prints out the information on the given file"""
        if not self.finished:
            return
        if not self.mimetype:
            print "Unknown media type"
            return
        print "Mime Type :\t", self.mimetype
        if not self.is_video and not self.is_audio:
            return
        print "Length :\t", self._time_to_string(max(self.audiolength, self.videolength))
        print "\tAudio:", self._time_to_string(self.audiolength), "\tVideo:", self._time_to_string(self.videolength)
        if self.is_video and self.videorate:
            print "Video :"
            print "\t%d x %d @ %d/%d fps" % (self.videowidth,
                                            self.videoheight,
                                            self.videorate.num, self.videorate.denom)
            if self.tags.has_key("video-codec"):
                print "\tCodec :", self.tags.pop("video-codec")
        if self.is_audio:
            print "Audio :"
            if self.audiofloat:
                print "\t%d channels(s) : %dHz @ %dbits (float)" % (self.audiochannels,
                                                                    self.audiorate,
                                                                    self.audiowidth)
            else:
                print "\t%d channels(s) : %dHz @ %dbits (int)" % (self.audiochannels,
                                                                  self.audiorate,
                                                                  self.audiodepth)
            if self.tags.has_key("audio-codec"):
                print "\tCodec :", self.tags.pop("audio-codec")
        for stream in self.otherstreams:
            if not stream == self.mimetype:
                print "Other unsuported Multimedia stream :", stream
        if self.tags:
            print "Additional information :"
            for tag in self.tags.keys():
                print "%20s :\t" % tag, self.tags[tag]

    def _unknown_type_cb(self, dbin, pad, caps):
        self.debug("unknown type : %s" % caps.to_string())
        # if we get an unknown type and we don't already have an
        # audio or video pad, we are finished !
        self.otherstreams.append(caps.to_string())
        if not self.is_video and not self.is_audio:
            self.finished = True
            self._finished()

    def _have_type_cb(self, typefind, prob, caps):
        self.mimetype = caps.to_string()

    def _notify_caps_cb(self, pad, args):
        caps = pad.get_negotiated_caps()
        if not caps:
            pad.info("no negotiated caps available")
            return
        pad.info("caps:%s" % caps.to_string)
        # the caps are fixed
        # We now get the total length of that stream
        q = gst.query_new_duration(gst.FORMAT_TIME)
        pad.info("sending position query")
        if pad.get_peer().query(q):
            format, length = q.parse_duration()
            pad.info("got position query answer : %d:%d" % (length, format))
        else:
            length = -1
            gst.warning("position query didn't work")

        # We store the caps and length in the proper location
        if "audio" in caps.to_string():
            self.audiocaps = caps
            self.audiolength = length
            self.audiorate = caps[0]["rate"]
            self.audiowidth = caps[0]["width"]
            self.audiochannels = caps[0]["channels"]
            if "x-raw-float" in caps.to_string():
                self.audiofloat = True
            else:
                self.audiodepth = caps[0]["depth"]
            if (not self.is_video) or self.videocaps:
                self._finished(True)
        elif "video" in caps.to_string():
            self.videocaps = caps
            self.videolength = length
            self.videowidth = caps[0]["width"]
            self.videoheight = caps[0]["height"]
            self.videorate = caps[0]["framerate"]
            if (not self.is_audio) or self.audiocaps:
                self._finished(True)

    def _new_decoded_pad_cb(self, dbin, pad, is_last):
        # Does the file contain got audio or video ?
        caps = pad.get_caps()
        gst.info("caps:%s" % caps.to_string())
        if "audio" in caps.to_string():
            self.is_audio = True
        elif "video" in caps.to_string():
            self.is_video = True
        else:
            self.warning("got a different caps.. %s" % caps.to_string())
            return
        if is_last and not self.is_video and not self.is_audio:
            self._finished(False)
            return
        # we connect a fakesink to the new pad...
        pad.info("adding queue->fakesink")
        fakesink = gst.element_factory_make("fakesink")
        queue = gst.element_factory_make("queue")
        self.add(fakesink, queue)
        queue.link(fakesink)
        sinkpad = fakesink.get_pad("sink")
        queuepad = queue.get_pad("sink")
        # ... and connect a callback for when the caps are fixed
        sinkpad.connect("notify::caps", self._notify_caps_cb)
        if pad.link(queuepad):
            pad.warning("##### Couldn't link pad to queue")
        queue.set_state(gst.STATE_PLAYING)
        fakesink.set_state(gst.STATE_PLAYING)
        gst.info('finished here')
