/*
 *  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 "mixer.h"


int mixer_init(mixer_t* m, const char* name, const char* device)
{
  assert(m != NULL);

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

  return 0;
}

int mixer_get_poll_fd_count(mixer_t* m)
{
  return snd_rawmidi_poll_descriptors_count(m->output_);
}

int mixer_get_poll_fds(mixer_t* m, struct pollfd *pfds, int npfds)
{
  return snd_rawmidi_poll_descriptors(m->output_, pfds, npfds);
}

int mixer_handle_revents(mixer_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, "MIXER: cannot get poll events: %s", snd_strerror(errno));
    return -1;
  }
  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
    error(0, 0, "MIXER: got POLLERR, POLLHUP or POLLNVAL");
    return -1;
  }
  if(!(revents & POLLOUT))
    return 0;

  u_int8_t buf[3] = { 0xB0, 0x00, 0x02 };
  int ret = snd_rawmidi_write(m->output_, buf, sizeof(buf));
  if(ret == -EAGAIN)
    return 0;
  if(ret < 0) {
    error(0, 0, "MIXER: cannot write to midi port: %s", snd_strerror(ret));
    return -1;
  }
  assert(ret == sizeof(buf)); // TODO: try again??
  if((err = snd_rawmidi_drain(m->output_)) < 0) {
    error(0, 0, "MIXER: cannot drain output: %s", snd_strerror(err));
    return -1;
  }

  return 0;
}