/*
 *  dolmetschctl
 *
 *
 *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of dolmetschctl.
 *
 *  dolmetschctl 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 3 of the License, or
 *  any later version.
 *
 *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <stdio.h>
#include <error.h>
#include <poll.h>
#include <assert.h>

#include "midi.h"

#define NOTE_EN 0x00
#define NOTE_DE 0x01
u_int8_t done_data_en[] = { 0xB0, NOTE_EN, 0x01, 0xB0, NOTE_DE, 0x00 };
u_int8_t done_data_de[] = { 0xB0, NOTE_EN, 0x00, 0xB0, NOTE_DE, 0x01 };

int midi_init(midi_t* m, const char* device)
{
  assert(m != NULL);

  m->input_ = NULL;
  m->output_ = NULL;
  memset(m->buf_, 0, sizeof(m->buf_));
  m->read_idx_ = 0;

  slist_init(&(m->done_data_), free);

  if(device) {
    int ret = snd_rawmidi_open(&(m->input_), &(m->output_), device, SND_RAWMIDI_NONBLOCK);
    if(ret < 0) {
      error(0, 0, "MIDI: cannot open port '%s': %s", device, snd_strerror(ret));
      return ret;
    }
  }

  return 0;
}

int midi_get_poll_fd_count(midi_t* m)
{
  assert(m);

  if(!m->input_ || !m->output_)
    return 0;

  m->in_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->input_);
  assert(m->in_pfds_cnt_ > 0);
  m->out_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->output_);
  assert(m->out_pfds_cnt_ > 0);

  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
}

int midi_get_poll_fds(midi_t* m, struct pollfd *pfds, int npfds)
{
  assert(m);

  if(!m->input_ || !m->output_)
    return 0;

  snd_rawmidi_poll_descriptors(m->input_, pfds, m->in_pfds_cnt_);
  snd_rawmidi_poll_descriptors(m->output_, &(pfds[m->in_pfds_cnt_]), npfds - m->in_pfds_cnt_);

  int pending_data = 0;
  if(m->done_data_.first_) {
    midi_done_data_t* d = (midi_done_data_t*)(m->done_data_.first_->data_);
    if(d->active_)
      pending_data = 1;
  }
  if(!pending_data) {
    int i;
    for(i = m->in_pfds_cnt_; i < npfds; ++i)
      pfds[i].events = 0;
  }
  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
}

void midi_lang_switch_done(void* data)
{
  assert(data);
  midi_done_data_t* d = data;
  d->active_ = 1;
}

static int midi_enqueue_lang_switch(midi_t* m, mixer_t* x, const char* lang, const u_int8_t* buf, int len)
{
  midi_done_data_t* done_data = malloc(sizeof(midi_done_data_t));
  assert(done_data);
  done_data->self_ = m;
  done_data->active_ = 0;
  done_data->buf_ = buf;
  done_data->len_ = len;
  done_data->write_idx_ = 0;
  assert(slist_add(&(m->done_data_), done_data));

  return mixer_switch_lang(x, lang, &midi_lang_switch_done, done_data);
}

static int midi_handle_note_on(midi_t* m, mixer_t* x)
{
  int ret = 0;
  switch(m->buf_[1]) {
  case NOTE_EN: ret = midi_enqueue_lang_switch(m, x, "en", done_data_en, sizeof(done_data_en)); break;
  case NOTE_DE: ret = midi_enqueue_lang_switch(m, x, "de", done_data_de, sizeof(done_data_de)); break;
  default: printf("ignoring unknown note\n"); break;
  }
  return ret;
}

static int midi_handle_note_off(midi_t* m, mixer_t* x)
{
  return 0;
}

static int midi_handle_message(midi_t* m, mixer_t* x)
{
  /* int i; */
  /* printf("MIDI: "); */
  /* for (i = 0; i < sizeof(m->buf_); ++i) */
  /*   printf("%02X%c", m->buf_[i], (i >= (sizeof(m->buf_)-1)) ? '\n' : ' '); */

  int ret = 0;
  switch(m->buf_[0]) {
  case 0x90: ret = midi_handle_note_on(m, x); break;
  case 0x80: ret = midi_handle_note_off(m, x); break;
  default: printf("ignoring unknown midi command\n"); break;
  }

  return ret;
}

static int midi_handle_in_revents(midi_t* m, struct pollfd *pfds, int npfds, mixer_t* x)
{
  int err;
  unsigned short revents;
  if((err = snd_rawmidi_poll_descriptors_revents(m->input_, pfds, npfds, &revents)) < 0) {
    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
    return -1;
  }
  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
    return -1;
  }
  if(!(revents & POLLIN))
    return 0;

  int ret = snd_rawmidi_read(m->input_, &(m->buf_[m->read_idx_]), sizeof(m->buf_) - m->read_idx_);
  if(ret == -EAGAIN)
    return 0;
  if(ret < 0) {
    error(0, 0, "MIDI: cannot read from midi port: %s", snd_strerror(ret));
    return -1;
  }
  m->read_idx_ += ret;
  if(m->read_idx_ >= sizeof(m->buf_)) {
    ret = midi_handle_message(m, x);
    memset(m->buf_, 0, sizeof(m->buf_));
    m->read_idx_ = 0;
    return ret;
  }

  return ret;
}

static int midi_handle_out_revents(midi_t* m, struct pollfd *pfds, int npfds)
{
  int err;
  unsigned short revents;
  if((err = snd_rawmidi_poll_descriptors_revents(m->output_, pfds, npfds, &revents)) < 0) {
    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
    return -1;
  }
  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
    return -1;
  }
  if(!(revents & POLLOUT))
    return 0;

  assert(m->done_data_.first_);
  midi_done_data_t* done_data = (midi_done_data_t*)(m->done_data_.first_->data_);
  assert(done_data);
  assert(done_data->active_);
  assert(done_data->buf_);

  int ret = snd_rawmidi_write(m->output_, &(done_data->buf_[done_data->write_idx_]), done_data->len_ - done_data->write_idx_);
  if(ret == -EAGAIN)
    return 0;
  if(ret < 0) {
    error(0, 0, "MIDI: cannot write to port: %s", snd_strerror(ret));
    return -1;
  }
  done_data->write_idx_ += ret;
  if(done_data->write_idx_ >= done_data->len_) {
    if((err = snd_rawmidi_drain(m->output_)) < 0) {
      error(0, 0, "MIDI: cannot drain output: %s", snd_strerror(err));
      return -1;
    }
    slist_remove(&(m->done_data_), done_data);
  }

  return 0;
}

int midi_handle_revents(midi_t* m, struct pollfd *pfds, int npfds, mixer_t* x)
{
  assert(m);

  if(!m->input_ || !m->output_)
    return 0;

  int ret = midi_handle_in_revents(m, pfds, m->in_pfds_cnt_, x);
  if(ret)
    return ret;

  return midi_handle_out_revents(m, &(pfds[m->in_pfds_cnt_]), m->out_pfds_cnt_);
}