/*
 *  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 <string.h>
#include <error.h>
#include <poll.h>
#include <assert.h>
#include <sys/types.h>
#include <dirent.h>

#include "mixer.h"

static void free_lang_entry(void* ptr)
{
  lang_t* l = ptr;
  assert(l);
  free(l->name_);
  slist_clear(&(l->cmds_));
  free(l);
}

static void free_task_entry(void* ptr)
{
  task_t* t = ptr;
  assert(t);
  free(t->buf_);
  free(t);
}

static int mixer_read_config_file(mixer_t* x, int dirfd, const char* filename)
{
  assert(dirfd > 0);

  int fd = openat(dirfd, filename, O_RDONLY);
  if(fd < 0) {
    error(0, errno, "erorr open('%s')", filename);
    return -1;
  }
  FILE* conf = fdopen(fd, "r");
  if(conf == NULL) {
    error(0, errno, "erorr fdopen('%s')", filename);
    return -1;
  }

  lang_t* lang = malloc(sizeof(lang_t));
  assert(lang);
  assert((lang->name_ = strdup(filename)));
  slist_init(&(lang->cmds_), free);
  assert(slist_add(&(x->langs_), lang));

  char buf[256];
  while(fgets(buf, sizeof(buf), conf) != NULL) {
    midi_cmd_t* cmd = malloc(sizeof(midi_cmd_t));
    if(!cmd) {
      error(0, ENOMEM, "can't create midi command stucture");
      break;
    }
    if(sscanf(buf, "%02hhx %02hhx %02hhx", &((*cmd)[0]), &((*cmd)[1]), &((*cmd)[2])) != 3) {
      continue;
    }
    assert(slist_add(&(lang->cmds_), cmd));
  }

  fclose(conf);
  return 0;
}

static int mixer_read_config(mixer_t* x)
{
  char path[1024];
  int ret = snprintf(path, sizeof(path), "%s/%s", ETCDIR, x->name_);
  assert(ret < sizeof(path));

  DIR* d = opendir(path);
  if(d == NULL) {
    error(0, errno, "MIXER: cannot open config directory '%s'", path);
    return -1;
  }

  struct dirent* entry;
  while((entry = readdir(d))) {
    if(entry->d_type == DT_REG) {
      if((ret = mixer_read_config_file(x, dirfd(d), entry->d_name)))
        break;
    }
  }

  if(closedir(d) < 0) {
    error(0, errno, "MIXER: cannot closeconfig directory '%s'", path);
    return -1;
  }

  return ret;
}

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

  x->name_ = name;
  x->output_ = NULL;
  x->pfd_count_ = 0;
  slist_init(&(x->langs_), free_lang_entry);
  slist_init(&(x->tasks_), free_task_entry);
  int ret = snd_rawmidi_open(NULL, &(x->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 mixer_read_config(x);;
}

static void mixer_print_midi_cmds(slist_t cmds)
{
  if(!slist_length(&(cmds)))
    printf("<no commands>\n");
  else {
    slist_element_t* tmp;
    for(tmp = cmds.first_; tmp; tmp = tmp->next_) {
      midi_cmd_t* c = (midi_cmd_t*)(tmp->data_);
      printf("  0x%02X 0x%02X 0x%02X\n", (*c)[0], (*c)[1], (*c)[2]);
    }
  }
}

void mixer_print_langs(mixer_t* x)
{
  assert(x);

  printf("languages:\n");
  if(!slist_length(&(x->langs_)))
    printf(" <no languages>\n");
  else {
    slist_element_t* tmp;
    for(tmp = x->langs_.first_; tmp; tmp = tmp->next_) {
      lang_t* l = (lang_t*)(tmp->data_);
      printf(" %s:\n", l->name_);
      mixer_print_midi_cmds(l->cmds_);
    }
  }
}

static u_int8_t* mixer_create_task_buf(slist_t cmds, int len)
{
  u_int8_t* buf = malloc(len);
  slist_element_t* tmp;
  int i;
  for(tmp = cmds.first_, i=0; tmp; tmp = tmp->next_, i+=sizeof(midi_cmd_t)) {
    midi_cmd_t* c = (midi_cmd_t*)(tmp->data_);
    memcpy(&(buf[i]), (*c), sizeof(midi_cmd_t));
  }
  return buf;
}

int mixer_switch_lang(mixer_t* x, const char* lang, void (*done_cb)(void*), void* done_data)
{
  slist_element_t* tmp;
  for(tmp = x->langs_.first_; tmp; tmp = tmp->next_) {
    lang_t* l = (lang_t*)(tmp->data_);
    if(!strcmp(lang, l->name_)) {
      int len = slist_length(&(l->cmds_));
      if(len > 0) {
        task_t* task = malloc(sizeof(task_t));
        assert(task);
        task->len_ = sizeof(midi_cmd_t) * len;
        assert((task->buf_ = mixer_create_task_buf(l->cmds_, task->len_)));
        task->write_idx_ = 0;
        task->done_cb_ = done_cb;
        task->done_data_ = done_data;
        assert(slist_add(&(x->tasks_), task));
      }
      return 0;
    }
  }
  error(0, 0, "requested language '%s' not found ... ignoring switch", lang);
  return -1;
}


void mixer_print_tasks(mixer_t* x)
{
  assert(x);

  printf("tasks:\n");
  if(!slist_length(&(x->tasks_)))
    printf(" <no tasks>\n");
  else {
    slist_element_t* tmp;
    for(tmp = x->tasks_.first_; tmp; tmp = tmp->next_) {
      task_t* t = (task_t*)(tmp->data_);
      int i;
      printf(" buf(%d) = ", t->len_);
      for(i = 0; i < t->len_; ++i) {
        printf("0x%02X%s", t->buf_[i], (i && !((i+1) % 3)) ? ", " : " ");
      }
      printf("\n write_idx = %d\n done = %016lX ( %016lX )\n\n", t->write_idx_, (int64_t)(t->done_cb_), (int64_t)(t->done_data_));
    }
  }
}

int mixer_get_poll_fd_count(mixer_t* x)
{
  return (x->pfd_count_ = snd_rawmidi_poll_descriptors_count(x->output_));
}

int mixer_get_poll_fds(mixer_t* x, struct pollfd *pfds, int npfds)
{
  if(slist_length(&(x->tasks_)))
    return snd_rawmidi_poll_descriptors(x->output_, pfds, npfds);
  else {
    int i;
    for(i = 0; i < x->pfd_count_; ++i)
      pfds[i].fd = -1;
  }
  return x->pfd_count_;
}

int mixer_handle_revents(mixer_t* x, struct pollfd *pfds, int npfds)
{
  assert(x);

  int err;
  unsigned short revents;
  if((err = snd_rawmidi_poll_descriptors_revents(x->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;

  assert(x->tasks_.first_);
  task_t* task = (task_t*)(x->tasks_.first_->data_);
  assert(task);
  assert(task->buf_);

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

  return 0;
}