# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# 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.
#  * Neither the name of pyglet nor the names of its
#    contributors may be used to endorse or promote products
#    derived from this software without specific prior written
#    permission.
#
# 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.
# ----------------------------------------------------------------------------

import sys

from . import lib_pulseaudio as pa
from pyglet.media import AbstractAudioDriver, AbstractAudioPlayer, \
    AbstractListener, MediaException, MediaEvent

import pyglet
_debug = pyglet.options['debug_media']

def check(result):
    if result < 0:
        error = pa.pa_context_errno(context._context)
        raise MediaException(pa.pa_strerror(error))
    return result

def check_not_null(value):
    if not value:
        error = pa.pa_context_errno(context._context)
        raise MediaException(pa.pa_strerror(error))
    return value


class PulseAudioMainLoopLock(object):
    def __init__(self, threaded_mainloop):
        self.threaded_mainloop = threaded_mainloop

    def lock(self):
        """Lock the threaded mainloop against events.  Required for all
        calls into PA."""
        pa.pa_threaded_mainloop_lock(self.threaded_mainloop)

    def unlock(self):
        """Unlock the mainloop thread."""
        pa.pa_threaded_mainloop_unlock(self.threaded_mainloop)

    def __enter__(self):
        self.lock()

    def __exit__(self, exc_type, exc_value, traceback):
        self.unlock()


class PulseAudioDriver(AbstractAudioDriver):
    _context = None
    def __init__(self):
        self.threaded_mainloop = pa.pa_threaded_mainloop_new()
        self.mainloop = pa.pa_threaded_mainloop_get_api(
            self.threaded_mainloop)
        self.lock = PulseAudioMainLoopLock(self.threaded_mainloop)

        self._players = pyglet.app.WeakSet()
        self._listener = PulseAudioListener(self)

    def create_audio_player(self, source_group, player):
        player = PulseAudioPlayer(source_group, player)
        self._players.add(player)
        return player

    def connect(self, server=None):
        """Connect to pulseaudio server.

        :Parameters:
            `server` : str
                Server to connect to, or ``None`` for the default local
                server (which may be spawned as a daemon if no server is
                found).
        """
        # TODO disconnect from old
        assert not self._context, 'Already connected'

        # Create context
        app_name = self.get_app_name()
        self._context = pa.pa_context_new(self.mainloop, app_name.encode('ASCII'))

        # Context state callback
        self._state_cb_func = pa.pa_context_notify_cb_t(self._state_cb)
        pa.pa_context_set_state_callback(self._context,
                                         self._state_cb_func, None)

        # Connect
        check(
            pa.pa_context_connect(self._context, server, 0, None)
        )


        with self.lock:
            check(
                pa.pa_threaded_mainloop_start(self.threaded_mainloop)
            )
            # Wait for context ready.
            self.wait()
            if pa.pa_context_get_state(self._context) != pa.PA_CONTEXT_READY:
                check(-1)

    def _state_cb(self, context, userdata):
        if _debug:
            print('context state cb')
        state = pa.pa_context_get_state(self._context)
        if state in (pa.PA_CONTEXT_READY,
                     pa.PA_CONTEXT_TERMINATED,
                     pa.PA_CONTEXT_FAILED):
            self.signal()

    def signal(self):
        """Signal the mainloop thread to break from a wait."""
        pa.pa_threaded_mainloop_signal(self.threaded_mainloop, 0)

    def wait(self):
        """Wait for a signal."""
        pa.pa_threaded_mainloop_wait(self.threaded_mainloop)

    def sync_operation(self, op):
        """Wait for an operation to be done or cancelled, then release it.
        Uses a busy-loop -- make sure a callback is registered to
        signal this listener."""
        while pa.pa_operation_get_state(op) == pa.PA_OPERATION_RUNNING:
            pa.pa_threaded_mainloop_wait(self.threaded_mainloop)
        pa.pa_operation_unref(op)

    def async_operation(self, op):
        """Release the operation immediately without waiting for it to
        complete."""
        pa.pa_operation_unref(op)

    def get_app_name(self):
        """Get the application name as advertised to the pulseaudio server."""
        # TODO move app name into pyglet.app (also useful for OS X menu bar?).
        return sys.argv[0]

    def dump_debug_info(self):
        print('Client version: ', pa.pa_get_library_version())

        print('Server:         ', pa.pa_context_get_server(self._context))
        print('Protocol:       ', pa.pa_context_get_protocol_version(
            self._context))
        print('Server protocol:', pa.pa_context_get_server_protocol_version(
            self._context))
        print('Local context:  ', (
            pa.pa_context_is_local(self._context) and 'Yes' or 'No'))

    def delete(self):
        """Completely shut down pulseaudio client."""
        with self.lock:
            pa.pa_context_disconnect(self._context)
            pa.pa_context_unref(self._context)

        pa.pa_threaded_mainloop_stop(self.threaded_mainloop)
        pa.pa_threaded_mainloop_free(self.threaded_mainloop)
        self.lock = None
        self.threaded_mainloop = None
        self.mainloop = None

    def get_listener(self):
        return self._listener


class PulseAudioListener(AbstractListener):
    def __init__(self, driver):
        self.driver = driver

    def _set_volume(self, volume):
        self._volume = volume
        for player in self.driver._players:
            player.set_volume(player._volume)

    def _set_position(self, position):
        self._position = position

    def _set_forward_orientation(self, orientation):
        self._forward_orientation = orientation

    def _set_up_orientation(self, orientation):
        self._up_orientation = orientation


class PulseAudioPlayer(AbstractAudioPlayer):
    _volume = 1.0

    def __init__(self, source_group, player):
        super(PulseAudioPlayer, self).__init__(source_group, player)

        self._events = []
        self._timestamps = []  # List of (ref_time, timestamp)
        self._write_index = 0  # Current write index (tracked manually)
        self._read_index_valid = False # True only if buffer has non-stale data

        self._clear_write = False
        self._buffered_audio_data = None
        self._underflow_is_eos = False
        self._buffer_underflow = False
        self._playing = False

        audio_format = source_group.audio_format
        assert audio_format

        # Create sample_spec
        sample_spec = pa.pa_sample_spec()
        if audio_format.sample_size == 8:
            sample_spec.format = pa.PA_SAMPLE_U8
        elif audio_format.sample_size == 16:
            if sys.byteorder == 'little':
                sample_spec.format = pa.PA_SAMPLE_S16LE
            else:
                sample_spec.format = pa.PA_SAMPLE_S16BE
        else:
            raise MediaException('Unsupported sample size')
        sample_spec.rate = audio_format.sample_rate
        sample_spec.channels = audio_format.channels
        channel_map = None
        self.sample_rate = audio_format.sample_rate

        with context.lock:
            # Create stream
            self.stream = pa.pa_stream_new(context._context,
                                           str(id(self)).encode('ASCII'),
                                           sample_spec,
                                           channel_map)
            check_not_null(self.stream)
            pa.pa_stream_ref(self.stream)

            # Callback trampoline for success operations
            self._success_cb_func = pa.pa_stream_success_cb_t(self._success_cb)
            self._context_success_cb_func = \
                pa.pa_context_success_cb_t(self._context_success_cb)

            # Callback for underflow (to detect EOS when expected pa_timestamp
            # does not get reached).
            self._underflow_cb_func = \
                pa.pa_stream_notify_cb_t(self._underflow_cb)
            pa.pa_stream_set_underflow_callback(self.stream,
                                                self._underflow_cb_func, None)

            # Callback for data write
            self._write_cb_func = pa.pa_stream_request_cb_t(self._write_cb)
            pa.pa_stream_set_write_callback(self.stream,
                                            self._write_cb_func, None)

            # Connect to sink
            device = None
            buffer_attr = None
            flags = (pa.PA_STREAM_START_CORKED |
                     pa.PA_STREAM_INTERPOLATE_TIMING |
                     pa.PA_STREAM_VARIABLE_RATE)

            sync_stream = None  # TODO use this
            check(
                pa.pa_stream_connect_playback(self.stream,
                                              device,
                                              buffer_attr,
                                              flags,
                                              None,
                                              sync_stream)
            )

            # Wait for stream readiness
            self._state_cb_func = pa.pa_stream_notify_cb_t(self._state_cb)
            pa.pa_stream_set_state_callback(self.stream,
                                            self._state_cb_func, None)
            while pa.pa_stream_get_state(self.stream) == pa.PA_STREAM_CREATING:
                context.wait()

            if pa.pa_stream_get_state(self.stream) != pa.PA_STREAM_READY:
                check(-1)

        if _debug:
            print('stream ready')

    def _state_cb(self, stream, data):
        context.signal()

    def _success_cb(self, stream, success, data):
        context.signal()

    def _context_success_cb(self, ctxt, success, data):
        context.signal()

    def _write_cb(self, stream, bytes, data):
        # If number of bytes is not supplied, query PulseAudio for it
        if bytes is None:
            bytes = pa.pa_stream_writable_size(self.stream)

        if _debug:
            print('write callback: %d bytes' % bytes)

        # Asynchronously update time
        if self._events:
            context.async_operation(
                pa.pa_stream_update_timing_info(self.stream,
                                                self._success_cb_func, None)
            )

        # Grab next audio packet, or leftovers from last callback.
        if self._buffered_audio_data:
            audio_data = self._buffered_audio_data
            self._buffered_audio_data = None
        else:
            audio_data = self.source_group.get_audio_data(bytes)

        seek_flag = pa.PA_SEEK_RELATIVE
        if self._clear_write:
            if _debug:
                print('seek PA_SEEK_RELATIVE_ON_READ')
            seek_flag = pa.PA_SEEK_RELATIVE_ON_READ
            self._clear_write = False

        # Keep writing packets until `bytes` is depleted
        while audio_data and bytes > 0:
            if _debug:
                print('packet', audio_data.timestamp)
            if _debug and audio_data.events:
                print('events', audio_data.events)
            for event in audio_data.events:
                event_index = self._write_index + event.timestamp * \
                    self.source_group.audio_format.bytes_per_second
                self._events.append((event_index, event))

            consumption = min(bytes, audio_data.length)

            check(
                pa.pa_stream_write(self.stream,
                                   audio_data.data,
                                   consumption,
                                   pa.pa_free_cb_t(0),  # Data is copied
                                   0,
                                   seek_flag)
            )

            seek_flag = pa.PA_SEEK_RELATIVE
            self._read_index_valid = True
            self._timestamps.append((self._write_index, audio_data.timestamp))
            self._write_index += consumption
            self._underflow_is_eos = False
            self._buffer_underflow = False

            if _debug:
                print('write', consumption)
            if consumption < audio_data.length:
                audio_data.consume(consumption, self.source_group.audio_format)
                self._buffered_audio_data = audio_data
                break

            bytes -= consumption
            if bytes > 0:
                audio_data = self.source_group.get_audio_data(bytes) #XXX name change

        if not audio_data:
            # Whole source group has been written.  Any underflow encountered
            # after now is the EOS.
            self._underflow_is_eos = True

            # In case the source group wasn't long enough to prebuffer stream
            # to PA's satisfaction, trigger immediate playback (has no effect
            # if stream is already playing).
            if self._playing:
                context.async_operation(
                     pa.pa_stream_trigger(self.stream,
                                          pa.pa_stream_success_cb_t(0), None)
                )

        self._process_events()

    def _underflow_cb(self, stream, data):
        self._process_events()

        if self._underflow_is_eos:
            self._sync_dispatch_player_event('on_eos')
            self._sync_dispatch_player_event('on_source_group_eos')
            self._underflow_is_eos = False
            self._buffer_underflow = True
            if _debug:
                print('eos')
        else:
            if _debug:
                print('underflow')
            # TODO: does PA automatically restart stream when buffered again?
            # XXX: sometimes receive an underflow after EOS... need to filter?

    def _process_events(self):
        if not self._events:
            return

        timing_info = pa.pa_stream_get_timing_info(self.stream)
        if not timing_info:
            if _debug:
                print('abort _process_events')
            return

        read_index = timing_info.contents.read_index

        while self._events and self._events[0][0] < read_index:
            _, event = self._events.pop(0)
            if _debug:
                print('dispatch event', event)
            event._sync_dispatch_to_player(self.player)

    def _sync_dispatch_player_event(self, event, *args):
        pyglet.app.platform_event_loop.post_event(self.player, event, *args)

    def __del__(self):
        try:
            self.delete()
        except:
            pass

    def delete(self):
        if _debug:
            print('delete')
        if not self.stream:
            return

        with context.lock:
            pa.pa_stream_disconnect(self.stream)

        # Wait for stream to terminate before continuing. Prevents cleaned up callbacks to be
        # called
        while pa.pa_stream_get_state(self.stream) != pa.PA_STREAM_TERMINATED:
            context.wait()

        pa.pa_stream_unref(self.stream)
        self.stream = None

    def clear(self):
        if _debug:
            print('clear')

        self._clear_write = True
        self._write_index = self._get_read_index()
        self._timestamps = []
        self._events = []

        with context.lock:
            self._read_index_valid = False
            context.sync_operation(
                pa.pa_stream_prebuf(self.stream, self._success_cb_func, None)
            )

    def play(self):
        if _debug:
            print('play')
        with context.lock:
            context.async_operation(
                pa.pa_stream_cork(self.stream, 0,
                                pa.pa_stream_success_cb_t(0), None)
            )

            # If whole stream has already been written, trigger immediate
            # playback.        
            if self._underflow_is_eos:
                context.async_operation(
                    pa.pa_stream_trigger(self.stream, 
                                        pa.pa_stream_success_cb_t(0), None)
                )

            if self._buffer_underflow:
                self._write_cb(self.stream, None, None)

        self._playing = True

    def stop(self):
        if _debug:
            print('stop')
        with context.lock:
            context.async_operation(
                    pa.pa_stream_cork(self.stream, 1,
                                pa.pa_stream_success_cb_t(0), None)
            )

        self._playing = False

    def _get_read_index(self):
        #time = pa.pa_usec_t()

        with context.lock:
            context.sync_operation(
                pa.pa_stream_update_timing_info(self.stream,
                                                self._success_cb_func, None)
            )

        timing_info = pa.pa_stream_get_timing_info(self.stream)
        if timing_info:
            read_index = timing_info.contents.read_index
        else:
            read_index = 0

        if _debug:
            print('_get_read_index ->', read_index)
        return read_index

    def _get_write_index(self):
        timing_info = pa.pa_stream_get_timing_info(self.stream)
        if timing_info:
            write_index = timing_info.contents.write_index
        else:
            write_index = 0

        if _debug:
            print('_get_write_index ->', write_index)
        return write_index

    def get_time(self):
        if not self._read_index_valid:
            if _debug:
                print('get_time <_read_index_valid = False> -> None')
            return

        read_index = self._get_read_index()

        write_index = 0
        timestamp = 0.0

        try:
            write_index, timestamp = self._timestamps[0]
            write_index, timestamp = self._timestamps[1]
            while read_index >= write_index:
                del self._timestamps[0]
                write_index, timestamp = self._timestamps[1]
        except IndexError:
            pass

        bytes_per_second = self.source_group.audio_format.bytes_per_second
        time = timestamp + (read_index - write_index) / float(bytes_per_second)

        if _debug:
            print('get_time ->', time)
        return time

    def set_volume(self, volume):
        self._volume = volume

        if not self.stream:
            return

        volume *= context._listener._volume

        cvolume = pa.pa_cvolume()
        volume = pa.pa_sw_volume_from_linear(volume)
        pa.pa_cvolume_set(cvolume,
                          self.source_group.audio_format.channels,
                          volume)

        with context.lock:
            idx = pa.pa_stream_get_index(self.stream)
            context.sync_operation(
                pa.pa_context_set_sink_input_volume(context._context,
                    idx,
                    cvolume,
                    self._context_success_cb_func,
                    None)
            )

    def set_pitch(self, pitch):
        pa.pa_stream_update_sample_rate(self.stream,
                                        int(pitch*self.sample_rate),
                                        self._success_cb_func,
                                        None)


def create_audio_driver():
    global context
    context = PulseAudioDriver()
    context.connect()
    if _debug:
        context.dump_debug_info()
    return context
