/**
 * unstickpixels – screen loop to try to unstick stuck pixels
 * 
 * Copyright © 2013, 2015  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This program 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
 * (at your option) any later version.
 * 
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <assert.h>
#include <time.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <sys/wait.h>

#include <libgamma.h>



#define t(...)  do { if (__VA_ARGS__) goto fail; } while (0)


#define WELCOME_MESSAGE								\
  "\033[H\033[01;31mWARNING: Do not use this if you have epilepsia.\033[00m\n"	\
  "\n"										\
  "It is recommended to massage the defective dots, whilst\n"			\
  "running this program.\n"							\
  "\n"										\
  "Press C-c to quit, and Enter to start (C-c will quit).\n"			\
  "\n"										\
  "\n"										\
  "You should not have to run this program. If the manufacture or\n"		\
  "reseller of your monitor refuse to replace or repair the monitor\n"  	\
  "that was broken, because of manufacturing error, when it was\n"		\
  "chiped to you, please consider yelling at the support, threaten\n"		\
  "to report the personally because of involvement in organised\n"		\
  "crime (not replacing hardware that was chipped broken when you\n"		\
  "selled it is a crime, and they do this in an organised fashion\n"		\
  "to make money), call their executive director persistently at\n"		\
  "inconvenient times, report them applicable board for consumer\n"		\
  "disputes/complaints or equivalent agency. If this program does\n"		\
  "not help, and the manufacture is Packard Bell, or its\n"			\
  "supersidiary Acer, tell them that you have tried a program\n"		\
  "that was prompted by the complete suckness and incapability\n"		\
  "to repair defects that they have agreed to repair. They suck!\n"		\
  "\n"										\
  "\n"										\
  "\n"										\
  "Copyright © 2013, 2015  Mattias Andrée (maandree@member.fsf.org)\n"  	\
  "\n"										\
  "This program is free software: you can redistribute it and/or modify\n"	\
  "it under the terms of the GNU General Public License as published by\n"	\
  "the Free Software Foundation, either version 3 of the License, or\n"		\
  "(at your option) any later version.\n"					\
  "\n"										\
  "This program is distributed in the hope that it will be useful,\n"		\
  "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"		\
  "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"		\
  "GNU General Public License for more details.\n"				\
  "\n"										\
  "You should have received a copy of the GNU General Public License\n"		\
  "along with this program.  If not, see <http://www.gnu.org/licenses/>."


/**
 * The name of the process.
 */
const char* argv0;

/**
 * Should we exit?
 */
static volatile sig_atomic_t please_exit = 0;

/**
 * The name of the site.
 */
static char* sitename = NULL;

/**
 * The site.
 */
static libgamma_site_state_t site;

/**
 * The partitions.
 */
static libgamma_partition_state_t* restrict* restrict parts = NULL;

/**
 * The CRTC:s.
 */
static libgamma_crtc_state_t* restrict* restrict crtcs = NULL;

/**
 * The ramps to use when displaying red.
 */
static libgamma_gamma_ramps16_t* restrict* restrict ramps_red   = NULL;

/**
 * The ramps to use when displaying green.
 */
static libgamma_gamma_ramps16_t* restrict* restrict ramps_green = NULL;

/**
 * The ramps to use when displaying blue.
 */
static libgamma_gamma_ramps16_t* restrict* restrict ramps_blue  = NULL;

/**
 * The original ramps.
 */
static libgamma_gamma_ramps16_t* restrict* restrict ramps_saved = NULL;

/**
 * 2: `site` initialised and all ramps saved.
 * 1: `site` initialised.
 * 0: nothing done.
 */
static int clut_state = 0;



/**
 * Parse interval argument.
 * 
 * @param   argv      The interval argument.
 * @param   interval  Output parameter for the interval.
 * @param   nonzero   With be set to zero if the interval is zero,
 *                    otherwise it is set to a non-zero value (1).
 * @return            0 on success, -1 on error.
 */
static int get_interval(const char* restrict arg, struct timespec* restrict interval, int* restrict nonzero)
{
  char* end;
  *nonzero = 1;
  errno = EINVAL;
  t (!isdigit(*arg));
  interval->tv_sec = (time_t)(errno = 0, strtol)(arg, &end, 10);
  t (errno || (errno = EINVAL, *end));
  interval->tv_nsec = interval->tv_sec % 1000;
  interval->tv_sec /= 1000;
  interval->tv_nsec *= 1000000L;
  if (interval->tv_sec == 0)
    if (interval->tv_nsec == 0)
      *nonzero = 0;
  return 0;
 fail:
  return -1;
}


/**
 * Wrapper for fork(3) that clocks all signals in the parent.
 * 
 * @return  See fork(3).
 */
static pid_t xfork(void)
{
  sigset_t set;
  pid_t pid;
  sigfillset(&set);
  sigprocmask(SIG_BLOCK, &set, 0);
  pid = fork();
  if (pid != -1)
    sigprocmask(SIG_UNBLOCK, &set, 0);
  return pid;
}


/**
 * Print usage information and exit.
 */
static void usage(void)
{
  exit(fprintf(stderr, "Usage: %s [-v] [--] [SLEEP_INTERVAL_MS]\n",
	       strrchr(argv0, '/') ? (strrchr(argv0, '/') + 1) : argv0
	       ) < 0 ? 1 : 2);
}


/**
 * Uninitialise the CLUT backend.
 * 
 * @return  0 on success, -1 on error.
 */
static void term_clut()
{
  size_t i;
  for (i = 0; crtcs && crtcs[i]; i++)
    {
      if (clut_state == 2)
	libgamma_crtc_set_gamma_ramps16(crtcs[i], *(ramps_saved[i]));
      libgamma_crtc_free(crtcs[i]);
      libgamma_gamma_ramps16_free(ramps_red[i]);
      libgamma_gamma_ramps16_free(ramps_green[i]);
      libgamma_gamma_ramps16_free(ramps_blue[i]);
      libgamma_gamma_ramps16_free(ramps_saved[i]);
    }
  free((void*)crtcs);
  free((void*)ramps_red);
  free((void*)ramps_green);
  free((void*)ramps_blue);
  free((void*)ramps_saved);
  for (i = 0; parts && parts[i]; i++)
    libgamma_partition_free(parts[i]);
  free((void*)parts);
  free((void*)sitename);
  if (clut_state)
    libgamma_site_destroy(&site);
  sitename = NULL;
  parts = NULL;
  crtcs = NULL;
  ramps_red = ramps_green = ramps_blue = ramps_saved = NULL;
  clut_state = 0;
}


/**
 * Initialise the CLUT backend.
 * 
 * @return  0 on success, -1 on error.
 */
static int init_clut()
{
  int method, error = 0;
  size_t i, j, k, n = 0;
  libgamma_crtc_information_t info;
  
  if (libgamma_list_methods(&method, 1, 0) < 1)
    {
      fprintf(stderr, "%s: could not get adjustment method, try '%s -v'.\n", argv0, argv0);
      return -1;
    }
  
  sitename = libgamma_method_default_site(method);
  if (sitename)
    {
      sitename = strdup(sitename);
      t (sitename == NULL);
    }
  t ((error = libgamma_site_initialise(&site, method, sitename)));
  sitename = NULL;
  
  clut_state++;
  
  if (site.partitions_available == 0)
    {
      fprintf(stderr, "%s: could find any graphics card/screen, try '%s -v'.\n", argv0, argv0);
      errno = 0;
      goto fail;
    }
  
  t (!(parts = calloc(site.partitions_available + 1, sizeof(*parts))));
  for (i = 0; i < site.partitions_available; i++)
    {
      t (!(parts[i] = calloc(1, sizeof(**parts))));
      t ((errno = libgamma_partition_initialise(parts[i], &site, i)));
      n += parts[i]->crtcs_available;
    }
  
  if (n == 0)
    {
      fprintf(stderr, "%s: could find any CRTC, try '%s -v'.\n", argv0, argv0);
      errno = 0;
      goto fail;
    }
  
  t (!(crtcs       = calloc(n + 1, sizeof(*crtcs))));
  t (!(ramps_red   = calloc(n + 1, sizeof(*ramps_red))));
  t (!(ramps_green = calloc(n + 1, sizeof(*ramps_green))));
  t (!(ramps_blue  = calloc(n + 1, sizeof(*ramps_blue))));
  t (!(ramps_saved = calloc(n + 1, sizeof(*ramps_saved))));
  for (i = k = 0; i < site.partitions_available; i++)
    for (j = 0; j < parts[i]->crtcs_available; j++, k++)
      {
	t (!(crtcs[k]       = calloc(1, sizeof(**crtcs))));
	t (!(ramps_red[k]   = calloc(1, sizeof(**ramps_red))));
	t (!(ramps_green[k] = calloc(1, sizeof(**ramps_green))));
	t (!(ramps_blue[k]  = calloc(1, sizeof(**ramps_blue))));
	t (!(ramps_saved[k] = calloc(1, sizeof(**ramps_saved))));
	t ((error = libgamma_crtc_initialise(crtcs[k], parts[i], j)));
	if (libgamma_get_crtc_information(&info, crtcs[k], LIBGAMMA_CRTC_INFO_GAMMA_SIZE))
	  t ((error = info.gamma_size_error));
	ramps_red[k]->red_size   = info.red_gamma_size;
	ramps_red[k]->green_size = info.green_gamma_size;
	ramps_red[k]->blue_size  = info.blue_gamma_size;
	*(ramps_saved[k]) = *(ramps_blue[k]) = *(ramps_green[k]) = *(ramps_red[k]);
	t (libgamma_gamma_ramps16_initialise(ramps_red[k]));
	t (libgamma_gamma_ramps16_initialise(ramps_green[k]));
	t (libgamma_gamma_ramps16_initialise(ramps_blue[k]));
	t (libgamma_gamma_ramps16_initialise(ramps_saved[k]));
	memset(ramps_red[k]->red,     ~0, ramps_red[k]->red_size     * sizeof(*(ramps_red[k]->red)));
	memset(ramps_red[k]->green,    0, ramps_red[k]->green_size   * sizeof(*(ramps_red[k]->green)));
	memset(ramps_red[k]->blue,     0, ramps_red[k]->blue_size    * sizeof(*(ramps_red[k]->blue)));
	memset(ramps_green[k]->red,    0, ramps_green[k]->red_size   * sizeof(*(ramps_green[k]->red)));
	memset(ramps_green[k]->green, ~0, ramps_green[k]->green_size * sizeof(*(ramps_green[k]->green)));
	memset(ramps_green[k]->blue,   0, ramps_green[k]->blue_size  * sizeof(*(ramps_green[k]->blue)));
	memset(ramps_blue[k]->red,     0, ramps_blue[k]->red_size    * sizeof(*(ramps_blue[k]->red)));
	memset(ramps_blue[k]->green,   0, ramps_blue[k]->green_size  * sizeof(*(ramps_blue[k]->green)));
	memset(ramps_blue[k]->blue,   ~0, ramps_blue[k]->blue_size   * sizeof(*(ramps_blue[k]->blue)));
	t ((error = libgamma_crtc_get_gamma_ramps16(crtcs[k], ramps_saved[k])));
      }
  
  clut_state++;
  
  return 0;
 fail:
  if (error)
    libgamma_perror(argv0, error);
  else if (errno)
    perror(argv0);
  term_clut();
  errno = 0;
  return -1;
}


/**
 * The loop, using the graphic cards' colour lookup tables.
 * 
 * @param  interval  The sleep interval, `NULL` for no sleep.
 */
static void loop_clut(const struct timespec* restrict interval)
{
  size_t i;
  int error;
  
  while (!please_exit)
    {
      for (i = 0; crtcs[i]; i++)
	t ((error = libgamma_crtc_set_gamma_ramps16(crtcs[i], *(ramps_red[i]))));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
      
      for (i = 0; crtcs[i]; i++)
	t ((error = libgamma_crtc_set_gamma_ramps16(crtcs[i], *(ramps_green[i]))));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
      
      for (i = 0; crtcs[i]; i++)
	t ((error = libgamma_crtc_set_gamma_ramps16(crtcs[i], *(ramps_blue[i]))));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
    }
  return;
 fail:
  if (error)
    libgamma_perror(argv0, error), errno = 0;
}


/**
 * The loop, using Linux VT.
 * 
 * @param  interval  The sleep interval, `NULL` for no sleep.
 */
static void loop_vt(const struct timespec* restrict interval)
{
  while (!please_exit)
    {
      t (printf("\033]P0FF0000\033[2J") == -1);
      t (fflush(stdout));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
      
      t (printf("\033]P000FF00\033[2J") == -1);
      t (fflush(stdout));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
      
      t (printf("\033]P00000FF\033[2J") == -1);
      t (fflush(stdout));
      if (interval)
	t ((errno = clock_nanosleep(CLOCK_MONOTONIC, 0, interval, NULL)));
    }
  return;
 fail:
  return;
}


/**
 * Signal handler for signals that exit the program.
 * 
 * @param  signo  The caught signal.
 */
static void sigexit(int signo)
{
  signal(signo, sigexit);
  please_exit = 1;
}


int main(int argc, char* argv[])
{
  int started = 0;
  int with_sleep = 0;
  struct timespec interval;
  int status, vt = 0, c = 0;
  pid_t pid = -1;
  int saved_errno;
  
  for (argv0 = (argc ? "unstickpixels" : *argv); c != -1;)
    switch ((c = getopt(argc, argv, "v")))
      {
      case 'v':  vt = 1;
      case -1:   break;
      case '?':  usage();
      default:   assert(0), abort();
      }
  if (optind < argc)
    t (get_interval(argv[optind++], &interval, &with_sleep));
  if (optind < argc)
    usage();
  
  printf("\033[?25l\033[H\033[2J");
  printf(WELCOME_MESSAGE);
  fflush(stdout);
  
  siginterrupt(SIGHUP, 1);
  siginterrupt(SIGTERM, 1);
  siginterrupt(SIGINT, 1);
  siginterrupt(SIGQUIT, 1);
  signal(SIGHUP, sigexit);
  signal(SIGTERM, sigexit);
  signal(SIGINT, sigexit);
  signal(SIGQUIT, sigexit);
  
  if (read(STDIN_FILENO, &started, 1) < 0)
    goto done;
  started = 1;
  
  if (vt)
    t (printf("\033[H") == -1);
  else
    t (printf("\033[H\033[2JIf you can read this, try '%s -v'.\n", argv0) == -1);
  t (fflush(stdout));
  
  t (vt ? 0 : init_clut());
  
  t (pid = xfork(), pid == -1);
  if (pid)
    goto parent;
  
  (vt ? loop_vt : loop_clut)(with_sleep ? &interval : NULL);
  
 fail:
  saved_errno = errno;
  if (!vt)
    term_clut();
  errno = saved_errno;
  if (pid == -1)
    {
      if (errno == EINVAL)
	usage();
      return (errno && (errno != EINTR)) ? (perror(argv0), 1) : 1;
    }
  return 0;
  
 parent:
  waitpid(pid, &status, 0);
 done:
  if (!vt)
    term_clut();
  printf("%s\033[?25h\033[H\033[2J", (started && vt) ? "\033]P0000000" : "");
  fflush(stdout);
  return WIFEXITED(status) ? WEXITSTATUS(status) : 0;
}