#!/usr/bin/env python
# -*- Mode: Python -*-
# vi:si:et:sw=4:sts=4:ts=4
#
# GStreamer python bindings
# Copyright (C) 2005 Edward Hervey <edward at fluendo dot com>
# Copyright (C) 2005 Thomas Vander Stichele <thomas at apestaart dot org>

# 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

import os
import sys
import pickle
import random as rand

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

import utils
from pygobject import gsignal
import sources
from leveller import Leveller

class Jukebox(gst.Bin):
    gsignal('done', str)
    gsignal('prerolled')        # emitted when at least 2 sources are ready
    gsignal('changed', str, gobject.TYPE_UINT64) # clocktime, filename
    gsignal('looped')

    def __init__(self, files, rms=0.2, loops=0, random=False,
                 caps="audio/x-raw-int,channels=2,rate=44100",
                 picklepath='level.pck'):
        # with pygtk 2.4 this call is needed for the gsignal to work
        self.__gobject_init__()

        self._target_rms = rms
        self._loopsleft = loops
        self._loopsdone = 0
        self._random = random
        self._picklepath = picklepath
        self._caps = gst.caps_from_string(caps)
        self._files = files[:] # copy
        self._levels = {} # filename -> rms, mixin, mixout, length
        self._prerolled = False
        self._playing = False
        self._scani = 0 # index into self._files for scanning
        self._playi = 0 # index into self._files for playing

        self._lastadded = None # last file added to composition
        self._lastposition = long(0) # last position where file was added

        if not len(files) > 1:
            raise TypeError, 'Must have at least 2 files'

        self._composition = gst.element_factory_make("gnlcomposition")
        self._composition.connect('pad-added', self._composition_pad_added_cb)
        self.add(self._composition)

        self._srcpad = None

        # load our pickle if it exists
        if os.path.exists(self._picklepath):
            file = open(self._picklepath)
            self._levels = pickle.load(file)
            file.close()

        # randomize our list if asked for
        if self._random:
            self._files = rand.sample(self._files, len(self._files))


    ## public API

    def preroll(self):
        # scan the first few files and start playing
        gst.debug("starting jukebox prerolling")
        self._scan()

    def start(self):
        ##
        ## FIXME : THIS SHOULD'T BE NEEDED !
        ## USE STATE CHANGES INSTEAD
        ## 
        if not self._prerolled:
            raise Exception, "baby"
        self.set_state(gst.STATE_PAUSED)

         
    ## Scanning private methods

    def _scan(self):
        # start a leveller for a new _toscan file
        if self._scani >= len(self._files):
            gst.debug("We're done scanning !")
            return

        file = self._files[self._scani]
        self._scani += 1

        if file in self._levels.keys():
            gst.debug("already did file %s" % file)
            self._check_prerolled()
            gobject.timeout_add(0, self._scan)
            return
            
        gst.debug("creating leveller for %s" % file)
        leveller = Leveller(file)
        leveller.connect('done', self._leveller_done_cb, file)
        gobject.timeout_add(0, leveller.start)
        ##gobject.idle_add(leveller.iterate)

    def _leveller_done_cb(self, l, reason, file):
        if reason != sources.EOS:
            gst.debug("Error: %s" % reason)
            return

        gst.debug("in: %s, out: %s" % (gst.TIME_ARGS(l.mixin),
                                       gst.TIME_ARGS(l.mixout)))
        gst.debug("rms: %f, %f dB" % (l.rms, l.rmsdB))

        # store infos
        self._levels[file] = (l.rms, l.mixin, l.mixout, l.length)
        
        gst.debug("writing level pickle")
        file = open(self._picklepath, "w")
        pickle.dump(self._levels, file)
        file.close()

        self._check_prerolled()
        self._scan()

        # clean up leveller after this handler
        gobject.timeout_add(0, l.clean)


    ## GnlSource-related methods

    def _new_gnl_source(self, location, start):
        """
        Creates a new GnlSource containing an AudioSource with the following
        properties correctly set:
        _ volume level
        _ priority
        _ duration
        The start position MUST be given
        """
        if not self._levels[location]:
            return None
        self.debug("Creating new GnlSource at %s for %s" % (gst.TIME_ARGS(start), location))
        idx = self._files.index(location) + self._loopsdone * len(self._files)
        rms, mixin, mixout, duration = self._levels[location]
        gnls = gst.element_factory_make("gnlsource", "source-%d-%s" % (idx, location))
        src = sources.AudioSource(location)
        gnls.add(src)

        # set volume
        level = 1.0
        if rms > self._target_rms:
            level = self._target_rms / rms
            gst.debug('setting volume of %f' % level)
        else:
            gst.debug('not going to go above 1.0 level')
        src.set_volume(level)

        # set proper position/duration/priority in composition
        gnls.props.priority = (2 * self._loopsdone) + 1 + (idx % 2)
        gnls.props.start = long(start)
        gnls.props.duration = long(duration)
        gnls.props.media_duration = long(duration)
        gnls.props.media_start = long(0)

        return gnls

    def _new_mixer(self, start, duration):
        gnlo = gst.element_factory_make("gnloperation")
        ad = gst.element_factory_make("adder")
        gnlo.add(ad)
        gnlo.props.sinks = 2
        gnlo.props.start = start
        gnlo.props.duration = duration
        gnlo.props.priority = 0

        return gnlo

    def _append_file(self, location):
        """
        Appends the given file to the composition, along with the proper mixer effect
        """
        self.debug("location:%s" % location)
        start = self._lastposition
        if self._lastadded:
            start += self._levels[self._lastadded][2]
            start -= self._levels[location][1]
        
        gnls = self._new_gnl_source(location, start)
        self._composition.add(gnls)

        if self._lastadded:
            # create the mixer
            duration = self._levels[self._lastadded][3] - self._levels[self._lastadded][2] + self._levels[location][1]
            mixer = self._new_mixer(start, duration)
            self._composition.add(mixer)

        self._lastposition = start
        self._lastadded = location
        
        self.debug("lastposition:%s , lastadded:%s" % (gst.TIME_ARGS(self._lastposition),
                                                       self._lastadded))

    def _check_prerolled(self):
        gst.debug("_check_prerolled: index: scan %d, play %d" % (
            self._scani, self._playi))
        if not self._prerolled and self._scani > self._playi + 1:
            self._prerolled = True
            # add initial sources here
            self._append_file(self._files[0])
            self._append_file(self._files[1])
            self.debug("now prerolled and ready to play")
            self.emit('prerolled')


    def _emit_changed(self, file, when):
        print "emitting changed for %s at %r" % (file, when)
        self.emit('changed', file, when)

    def _source_clean(self, source):
        source.set_state(gst.STATE_NULL)
        self.remove(source)
        source.clean()

    ## composition callbacks

    def _composition_pad_added_cb(self, comp, pad):
        if self._srcpad:
            return
        self.debug("Ghosting source pad %s" % pad)
        self._srcpad = gst.GhostPad("src", pad)
        self.add_pad(self._srcpad)

    ## gst.Bin/Element virtual methods

    def do_handle_message(self, message):
        self.debug("got message %s / %s / %r" % (message.src.get_name(), message.type.first_value_name, message))

        # chaining up
        gst.Bin.do_handle_message(self, message)

    def do_state_change(self, transition):
        if not self._prerolled:
            gst.error("Call Jukebox.preroll() before!")
            return gst.STATE_CHANGE_FAILURE
        # chaining up
        return gst.Bin.do_state_change(self, message)
        
gobject.type_register(Jukebox)
        
# helper functions
def _find_elements_recurse(element):
    if not isinstance(element, gst.Bin):
        return [element, ]
    l = []
    for e in element.elements():
        l.extend(_find_elements_recurse(e))
    return l

def _find_unconnected_pad(bin, direction):
    for e in _find_elements_recurse(bin):
        for p in e.pads():
            if p.get_direction() == direction and not p.get_peer():
                return p

    return None

# run us to test
if __name__ == "__main__":
    main = gobject.MainLoop()
    pipeline = gst.Pipeline('jukebox')
    list = open(sys.argv[1]).read().rstrip().split('\n')
    print list
    #source = Jukebox(list, random=True, loops=-1)
    source = Jukebox(list, random=True, loops=1)

    def _jukebox_prerolled_cb(jukebox):
        print "prerolled"
        _start()

    def _jukebox_changed_cb(jukebox, filename, when):
        print "changed file to %s at %s" % (filename, float(when) / gst.TIME_ARGS(gst.SECOND))

    def _jukebox_looped_cb(jukebox):
        print "jukebox looped"
        
    def _start():
        source.start()
        print "setting pipeline to PLAYING"
        pipeline.set_state(gst.STATE_PLAYING)
        print "set pipeline to PLAYING"

    def jukebox_pad_added(comp, pad, sinkpad):
        pad.link(sinkpad)

    def jukebox_message(bus, message):
        if message.type == gst.MESSAGE_ERROR:
            print "Error: %s" % message.parse_error()
            main.quit()
        elif message.type == gst.MESSAGE_EOS:
            print "done"
            main.quit()

    source.connect('prerolled', _jukebox_prerolled_cb)
    source.connect('changed', _jukebox_changed_cb)
    source.connect('looped', _jukebox_looped_cb)
    source.preroll()
    pipeline.add(source)

    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect("message", jukebox_message)

    p = "alsasink"
    if len(sys.argv) > 2:
        p = " ".join(sys.argv[2:])
    
    print "parsing output pipeline %s" % p
    sinkbin = gst.parse_launch("bin.( %s )" % p)
    pipeline.add(sinkbin)
    apad = _find_unconnected_pad(sinkbin, gst.PAD_SINK)
    if not apad:
        raise TypeError, "No unconnected sink pad found in bin %r" % sinkbin
    sinkpad = gst.GhostPad("sink", apad)
    sinkbin.add_pad(sinkpad)
    source.connect('pad-added', jukebox_pad_added, sinkpad)

    print "Going into main loop"
    sys.stdout.flush()
    main.run()
    print "Left main loop"
    sys.stdout.flush()

    pipeline.set_state(gst.STATE_NULL)