# Copyright (C) 2009-2010 Aren Olson
#
# 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 2, 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, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
#
# The developers of the Exaile media player hereby grant permission
# for non-GPL compatible GStreamer and Exaile plugins to be used and
# distributed together with GStreamer and Exaile. This permission is
# above and beyond the permissions granted by the GPL license by which
# Exaile is covered. If you modify this code, you may extend this
# exception to your version of the code, but you are not obligated to
# do so. If you do not wish to do so, delete this exception statement
# from your version.

from xl import providers, event, settings
from xl.player.pipe import ElementBin

import gst

try:
    import replaygainprefs
    def get_preferences_pane():
        return replaygainprefs
except: # fail gracefully if we cant set up the UI
    pass

NEEDED_ELEMS = ["rgvolume", "rglimiter"]

def enable(exaile):
    for elem in NEEDED_ELEMS:
        if not gst.element_factory_find(elem):
            raise ImportError, "Needed gstreamer element %s missing."%elem
    providers.register("stream_element", ReplaygainVolume)
    providers.register("stream_element", ReplaygainLimiter)

def disable(exaile):
    providers.unregister("stream_element", ReplaygainVolume)
    providers.unregister("stream_element", ReplaygainLimiter)


class ReplaygainVolume(ElementBin):
    """
        Handles replaygain volume adjustment and pre-amp.

        Placed at 20 in the pipeline, since most elements should do their
        processing after it.
    """
    index = 20
    name = "rgvolume"
    def __init__(self):
        ElementBin.__init__(self, name=self.name)
        self.audioconvert = gst.element_factory_make("audioconvert")
        self.elements[40] = self.audioconvert
        self.rgvol = gst.element_factory_make("rgvolume")
        self.elements[50] = self.rgvol
        self.setup_elements()

        event.add_callback(self._on_option_set, "replaygain_option_set")

        # load settings
        for x in ("album-mode", "pre-amp", "fallback-gain"):
            self._on_option_set("replaygain_option_set", None,
                    "replaygain/%s"%x)

    def _on_option_set(self, name, object, data):
        if data == "replaygain/album-mode":
            self.rgvol.set_property("album-mode",
                    settings.get_option("replaygain/album-mode", True))
        elif data == "replaygain/pre-amp":
            self.rgvol.set_property("pre-amp",
                    settings.get_option("replaygain/pre-amp", 0))
        elif data == "replaygain/fallback-gain":
            self.rgvol.set_property("fallback-gain",
                    settings.get_option("replaygain/fallback-gain", 0))


class ReplaygainLimiter(ElementBin):
    """
        Implements clipping protection.

        Placed at 80 in the pipeline so that other elements can come
        before it if necessary.
    """
    index = 80
    name = "rglimiter"
    def __init__(self):
        ElementBin.__init__(self, name=self.name)
        self.rglimit = gst.element_factory_make("rglimiter")
        self.elements[50] = self.rglimit
        self.audioconvert = gst.element_factory_make("audioconvert")
        self.elements[60] = self.audioconvert
        self.setup_elements()

        event.add_callback(self._on_option_set, "replaygain_option_set")
        self._on_option_set("replaygain_option_set", None,
                "replaygain/clipping-protection")

    def _on_option_set(self, name, object, data):
        if data == "replaygain/clipping-protection":
            self.rglimit.set_property("enabled",
                    settings.get_option("replaygain/clipping-protection",
                        True))

