/*
 * gstfluidsynth - fluidsynth plugin for gstreamer
 *
 * Copyright 2013 Wim Taymans <wim.taymans@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library 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.
 */

/**
 * SECTION:element-fluidsynth
 * @see_also: timidity, wildmidi
 *
 * This element renders midi-events as audio streams using
 * <ulink url="http://fluidsynth.sourceforge.net//">Fluidsynth</ulink>.
 * It offers better sound quality compared to the timidity or wildmidi element.
 *
 * <refsect2>
 * <title>Example pipeline</title>
 * |[
 * gst-launch-1.0 filesrc location=song.mid ! midiparse ! fluidsynth ! pulsesink
 * ]| This example pipeline will parse the midi and render to raw audio which is
 * played via pulseaudio.
 * </refsect2>
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#define FLUIDSYNTH_RATE 44100
#define FLUIDSYNTH_BPS  (4 * 2)

#include <gst/gst.h>
#include <string.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <gst/audio/audio.h>

#include "gstfluidsynth.h"

GST_DEBUG_CATEGORY_STATIC (gst_fluidsynth_debug);
#define GST_CAT_DEFAULT gst_fluidsynth_debug

enum
{
  /* FILL ME */
  LAST_SIGNAL
};

enum
{
  PROP_0,
  /* FILL ME */
};

static void gst_fluidsynth_finalize (GObject * object);

static gboolean gst_fluidsynth_sink_event (GstPad * pad, GstObject * parent,
    GstEvent * event);

static GstStateChangeReturn gst_fluidsynth_change_state (GstElement * element,
    GstStateChange transition);

static GstFlowReturn gst_fluidsynth_chain (GstPad * sinkpad, GstObject * parent,
    GstBuffer * buffer);

static void gst_fluidsynth_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_fluidsynth_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-midi-event")
    );

static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-raw, "
        "format = (string) " GST_AUDIO_NE (F32) ", "
        "rate = (int) " G_STRINGIFY (FLUIDSYNTH_RATE) ", "
        "channels = (int) 2, " "layout = (string) interleaved"));

#define parent_class gst_fluidsynth_parent_class
G_DEFINE_TYPE (GstFluidsynth, gst_fluidsynth, GST_TYPE_ELEMENT);

/* initialize the plugin's class */
static void
gst_fluidsynth_class_init (GstFluidsynthClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  gobject_class->finalize = gst_fluidsynth_finalize;
  gobject_class->set_property = gst_fluidsynth_set_property;
  gobject_class->get_property = gst_fluidsynth_get_property;

  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&src_factory));
  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&sink_factory));

  gst_element_class_set_static_metadata (gstelement_class, "Fluidsynth",
      "Codec/Decoder/Audio",
      "Midi Synthesizer Element", "Wim Taymans <wim.taymans@gmail.com>");

  gstelement_class->change_state = gst_fluidsynth_change_state;
}

/* initialize the new element
 * instantiate pads and add them to element
 * set functions
 * initialize structure
 */
static void
gst_fluidsynth_init (GstFluidsynth * filter)
{
  filter->sinkpad = gst_pad_new_from_static_template (&sink_factory, "sink");
  gst_pad_set_event_function (filter->sinkpad, gst_fluidsynth_sink_event);
  gst_pad_set_chain_function (filter->sinkpad, gst_fluidsynth_chain);
  gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);

  filter->srcpad = gst_pad_new_from_static_template (&src_factory, "src");
  gst_pad_use_fixed_caps (filter->srcpad);
  gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);
}

static void
gst_fluidsynth_finalize (GObject * object)
{
  G_OBJECT_CLASS (parent_class)->finalize (object);
}

#if 0
static GstBuffer *
gst_fluidsynth_clip_buffer (GstFluidsynth * fluidsynth, GstBuffer * buffer)
{
  guint64 start, stop;
  guint64 new_start, new_stop;
  gint64 offset, length;

  /* clipping disabled for now */
  return buffer;

  start = GST_BUFFER_OFFSET (buffer);
  stop = GST_BUFFER_OFFSET_END (buffer);

  if (!gst_segment_clip (&fluidsynth->segment, GST_FORMAT_DEFAULT,
          start, stop, &new_start, &new_stop)) {
    gst_buffer_unref (buffer);
    return NULL;
  }

  if (start == new_start && stop == new_stop)
    return buffer;

  offset = new_start - start;
  length = new_stop - new_start;

  buffer = gst_buffer_make_writable (buffer);
  gst_buffer_resize (buffer, offset, length);

  GST_BUFFER_OFFSET (buffer) = new_start;
  GST_BUFFER_OFFSET_END (buffer) = new_stop;
  GST_BUFFER_TIMESTAMP (buffer) =
      gst_util_uint64_scale_int (new_start, GST_SECOND, FLUIDSYNTH_RATE);
  GST_BUFFER_DURATION (buffer) =
      gst_util_uint64_scale_int (new_stop, GST_SECOND, FLUIDSYNTH_RATE) -
      GST_BUFFER_TIMESTAMP (buffer);

  return buffer;
}
#endif

static gboolean
gst_fluidsynth_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
  gboolean res;
  GstFluidsynth *fluidsynth = GST_FLUIDSYNTH (parent);

  GST_DEBUG_OBJECT (pad, "%s event received", GST_EVENT_TYPE_NAME (event));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_CAPS:
    {
      GstCaps *caps;

      caps = gst_caps_new_simple ("audio/x-raw",
          "format", G_TYPE_STRING, GST_AUDIO_NE (F32),
          "rate", G_TYPE_INT, FLUIDSYNTH_RATE,
          "channels", G_TYPE_INT, 2,
          "layout", G_TYPE_STRING, "interleaved", NULL);

      res = gst_pad_push_event (fluidsynth->srcpad, gst_event_new_caps (caps));
      gst_caps_unref (caps);
      break;
    }
    case GST_EVENT_SEGMENT:
      gst_event_copy_segment (event, &fluidsynth->segment);
      GST_DEBUG_OBJECT (fluidsynth, "configured segment %" GST_SEGMENT_FORMAT,
          fluidsynth->segment);
      res = gst_pad_event_default (pad, parent, event);
      break;
    case GST_EVENT_EOS:
      /* FIXME, push last samples */
      res = gst_pad_event_default (pad, parent, event);
      break;
    default:
      res = gst_pad_event_default (pad, parent, event);
      break;
  }
  return res;
}

static GstFlowReturn
produce_samples (GstFluidsynth * fluidsynth, GstClockTime pts, guint64 sample)
{
  GstClockTime duration, timestamp;
  guint64 samples, offset;
  GstMapInfo info;
  GstBuffer *outbuf;

  samples = sample - fluidsynth->last_sample;
  duration = pts - fluidsynth->last_pts;
  offset = fluidsynth->last_sample;
  timestamp = fluidsynth->last_pts;

  fluidsynth->last_pts = pts;
  fluidsynth->last_sample = sample;

  if (samples == 0)
    return GST_FLOW_OK;

  GST_DEBUG_OBJECT (fluidsynth, "duration %" GST_TIME_FORMAT
      ", samples %u", GST_TIME_ARGS (duration), samples);

  outbuf = gst_buffer_new_allocate (NULL, samples * FLUIDSYNTH_BPS, NULL);

  gst_buffer_map (outbuf, &info, GST_MAP_WRITE);
  fluid_synth_write_float (fluidsynth->synth, samples, info.data, 0, 2,
      info.data, 1, 2);
  gst_buffer_unmap (outbuf, &info);

  GST_BUFFER_DTS (outbuf) = timestamp;
  GST_BUFFER_PTS (outbuf) = timestamp;
  GST_BUFFER_DURATION (outbuf) = duration;
  GST_BUFFER_OFFSET (outbuf) = offset;
  GST_BUFFER_OFFSET_END (outbuf) = offset + samples;

  return gst_pad_push (fluidsynth->srcpad, outbuf);
}

static void
handle_buffer (GstFluidsynth * fluidsynth, GstBuffer * buffer)
{
  GstMapInfo info;
  guint8 event, channel;

  gst_buffer_map (buffer, &info, GST_MAP_READ);

  event = info.data[0];
  channel = event & 0x0f;

  GST_DEBUG_OBJECT (fluidsynth, "event 0x%02x channel %d", event, channel);

  switch (event & 0xf0) {
    case 0xf0:
      switch (event) {
        case 0xff:
          fluid_synth_system_reset (fluidsynth->synth);
          break;
        case 0xf0:
        case 0xf7:
          fluid_synth_sysex (fluidsynth->synth, (char *) info.data + 1,
              info.size - 1, NULL, NULL, NULL, 0);

          break;
        default:
          GST_WARNING_OBJECT (fluidsynth, "unhandled event 0x%02x", event);
          break;
      }
      break;
    default:
    {
      guint8 p1, p2;

      p1 = info.size > 1 ? info.data[1] & 0x7f : 0;
      p2 = info.size > 2 ? info.data[2] & 0x7f : 0;

      switch (event & 0xf0) {
        case 0x80:
          fluid_synth_noteoff (fluidsynth->synth, channel, p1);
          break;
        case 0x90:
          fluid_synth_noteon (fluidsynth->synth, channel, p1, p2);
          break;
        case 0xA0:
          /* aftertouch */
          break;
        case 0xB0:
          fluid_synth_cc (fluidsynth->synth, channel, p1, p2);
          break;
        case 0xC0:
          fluid_synth_program_change (fluidsynth->synth, channel, p1);
          break;
        case 0xD0:
          fluid_synth_channel_pressure (fluidsynth->synth, channel, p1);
          break;
        case 0xE0:
          fluid_synth_pitch_bend (fluidsynth->synth, channel, (p2 << 7) | p1);
          break;
        default:
          break;
      }
      break;
    }
  }
  gst_buffer_unmap (buffer, &info);
}

static GstFlowReturn
gst_fluidsynth_chain (GstPad * sinkpad, GstObject * parent, GstBuffer * buffer)
{
  GstFlowReturn res = GST_FLOW_OK;
  GstFluidsynth *fluidsynth;
  GstClockTime pts;

  fluidsynth = GST_FLUIDSYNTH (parent);

  pts = GST_BUFFER_PTS (buffer);

  if (pts != GST_CLOCK_TIME_NONE) {
    guint64 sample =
        gst_util_uint64_scale_int (pts, FLUIDSYNTH_RATE, GST_SECOND);

    if (fluidsynth->last_pts == GST_CLOCK_TIME_NONE) {
      fluidsynth->last_pts = pts;
      fluidsynth->last_sample = sample;
    } else if (fluidsynth->last_pts < pts) {
      /* generate samples for the elapsed time */
      res = produce_samples (fluidsynth, pts, sample);
    }
  }

  if (res == GST_FLOW_OK) {
    handle_buffer (fluidsynth, buffer);
  }
  gst_buffer_unref (buffer);

  return res;
}

static gboolean
gst_fluidsynth_open (GstFluidsynth * fluidsynth)
{
  if (fluidsynth->settings == NULL) {
    fluidsynth->settings = new_fluid_settings ();
    fluidsynth->synth = new_fluid_synth (fluidsynth->settings);
    /* FIXME configure path */
    fluidsynth->soundfont = fluid_synth_sfload (fluidsynth->synth,
        "/usr/share/sounds/sf2/FluidR3_GM.sf2", 1);
    fluid_synth_set_chorus_on (fluidsynth->synth, TRUE);
    fluid_synth_set_gain (fluidsynth->synth, 0.2);
    fluid_synth_set_polyphony (fluidsynth->synth, 256);
    fluid_synth_set_reverb_on (fluidsynth->synth, TRUE);
    fluid_synth_set_sample_rate (fluidsynth->synth, FLUIDSYNTH_RATE);
  }

  return TRUE;
}

static gboolean
gst_fluidsynth_close (GstFluidsynth * fluidsynth)
{
  if (fluidsynth->settings) {
    fluid_synth_sfunload (fluidsynth->synth, fluidsynth->soundfont, 1);
    delete_fluid_synth (fluidsynth->synth);
    delete_fluid_settings (fluidsynth->settings);
    fluidsynth->settings = NULL;
  }
  return TRUE;
}

static GstStateChangeReturn
gst_fluidsynth_change_state (GstElement * element, GstStateChange transition)
{
  GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
  GstFluidsynth *fluidsynth = GST_FLUIDSYNTH (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      if (!gst_fluidsynth_open (fluidsynth))
        goto open_failed;
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
      break;
    default:
      break;
  }

  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

  switch (transition) {
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      gst_fluidsynth_close (fluidsynth);
      break;
    default:
      break;
  }

  return ret;

  /* ERRORS */
open_failed:
  {
    GST_ERROR_OBJECT (fluidsynth, "could not open");
    return GST_STATE_CHANGE_FAILURE;
  }
}

static void
gst_fluidsynth_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_fluidsynth_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (gst_fluidsynth_debug, "fluidsynth",
      0, "Fluidsynth plugin");

  return gst_element_register (plugin, "fluidsynth",
      GST_RANK_SECONDARY, GST_TYPE_FLUIDSYNTH);
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    fluidsynth,
    "Fluidsynth Plugin",
    plugin_init, VERSION, "LGPL", GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)