/**
 * cg-tools -- Cooperative gamma-enabled tools
 * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
 * 
 * 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 "cg-base.h"

#include <libclut.h>

#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>



/**
 * The default filter priority for the program
 */
const int64_t default_priority = 0;

/**
 * The default class for the program
 */
char default_class[] = PKGNAME "::cg-gamma::standard";



/**
 * -d: keep process alive and remove filter on death
 */
static int dflag = 0;

/**
 * -x: remove filter rather than adding it
 */
static int xflag = 0;

/**
 * -f: gamma listing file
 */
static char* fflag = NULL;

/**
 * The gamma of the red channel
 */
static double rgamma = 1;

/**
 * The gamma of the green channel
 */
static double ggamma = 1;

/**
 * The gamma of the blue channel
 */
static double bgamma = 1;

/**
 * `NULL`-terminated list of output
 * names listed in the configuration file
 */
static char** names = NULL;

/**
 * The gamma of the red channel on monitor
 * with same index in `names`
 */
static double* rgammas = NULL;

/**
 * The gamma of the green channel on monitor
 * with same index in `names`
 */
static double* ggammas = NULL;

/**
 * The gamma of the blue channel on monitor
 * with same index in `names`
 */
static double* bgammas = NULL;



/**
 * Print usage information and exit
 */
void usage(void)
{
  fprintf(stderr,
	  "Usage: %s [-M method] [-S site] [-c crtc]... [-R rule] "
	  "(-x | [-p priority] [-d] [-f file | all | red green blue])\n",
	  argv0);
  exit(1);
}


/**
 * Perform cleanup so valgrind output is clean
 * 
 * @param   ret  The value to return
 * @return       `ret` is returned as is
 */
static int cleanup(int ret)
{
  int saved_errno = errno;
  if (names != NULL)
    {
      char** p = names;
      while (*p)
	free(*p++);
    }
  free(names);
  free(rgammas);
  free(ggammas);
  free(bgammas);
  errno = saved_errno;
  return ret;
}


/**
 * Handle a command line option
 * 
 * @param   opt  The option, it is a NUL-terminate two-character
 *               string starting with either '-' or '+', if the
 *               argument is not recognised, call `usage`. This
 *               string will not be "-M", "-S", "-c", "-p", or "-R".
 * @param   arg  The argument associated with `opt`,
 *               `NULL` there is no next argument, if this
 *               parameter is `NULL` but needed, call `usage`
 * @return       0 if `arg` was not used,
 *               1 if `arg` was used,
 *               -1 on error
 */
int handle_opt(char* opt, char* arg)
{
  if (opt[0] == '-')
    switch (opt[1])
      {
      case 'd':
	if (dflag || xflag)
	  usage();
	dflag = 1;
	break;
      case 'x':
	if (xflag || dflag)
	  usage();
	xflag = 1;
	break;
      case 'f':
	if (fflag || !(fflag = arg))
	  usage();
	return 1;
      default:
	usage();
      }
  return 0;
}


/**
 * Get the pathname of a configuration file
 * 
 * @param   confname   The filename (excluding directory) of the configuration file
 * @return             The full pathname of the configuration file, `NULL` on error
 */
static char* get_conf_file(const char* restrict confname)
{
  struct passwd* pw;
  char* path;
  
  pw = getpwuid(getuid());
  if ((pw == NULL) || (pw->pw_dir == NULL))
    return NULL;
  
  path = malloc(strlen(pw->pw_dir) + strlen(confname) + sizeof("/.config/"));
  if (path == NULL)
    return NULL;
  
  sprintf(path, "%s/.config/%s", pw->pw_dir, confname);
  
  if (access(path, F_OK) < 0)
    sprintf(path, "/etc/%s", confname);
  
  return path;
}


/**
 * Parse a non-negative double encoded as a string
 * 
 * @param   out  Output parameter for the value
 * @param   str  The string
 * @retunr       Zero on success, -1 if the string is invalid
 */
static int parse_double(double* restrict out, const char* restrict str)
{
  char* end;
  errno = 0;
  *out = strtod(str, &end);
  if (errno || (*out < 0) || isinf(*out) || isnan(*out) || *end)
    return -1;
  if (!*str || !strchr("0123456789.", *str))
    return -1;
  return 0;
}


/**
 * Parse gamma configuration file
 * 
 * @param   pathname  The pathname of the file
 * @return            Zero on success, -1 on error
 */
static int parse_gamma_file(const char* restrict pathname)
{
  int fd, saved_errno;
  char* line = NULL;
  size_t size = 0, lineno = 0, ptr = 0, alloc = 0;
  ssize_t n;
  FILE* f = NULL;
  char* p;
  char* q;
  char* r;
  char* g;
  char* b;
  
  fd = open(pathname, O_RDONLY);
  if (fd == -1)
    return -1;
  
  f = fdopen(fd, "rb");
  if (f == NULL)
    goto fail;
  
  while (n = getline(&line, &size, f), n >= 0)
    {
      lineno += 1;
      
      if ((n > 0) && (line[n - 1] == '\n'))
	line[n - 1] = '\0';
      p = line;
      while ((*p == ' ') || (*p == '\t')) p++;
      if ((!*p) || (*p == '#'))
	continue;
      
      r = strpbrk(line, " \t");
      if (r == NULL)
	goto bad;
      while (r[1] == ' ' || r[1] == '\t') r++;
      g = strpbrk(r + 1, " \t");
      if (g == NULL)
	goto bad;
      while (g[1] == ' ' || g[1] == '\t') g++;
      b = strpbrk(g + 1, " \t");
      if (b == NULL)
	goto bad;
      while (b[1] == ' ' || b[1] == '\t') b++;
      
      for (;;)
	{
	  q = strpbrk(b + 1, " \t");
	  if (q == NULL)
	    break;
	  while (q[1] == ' ' || q[1] == '\t') q++;
	  if (!*q)
	    break;
	  r = g, g = b, b = q;
	}
      
      *r++ = '\0';
      *g++ = '\0';
      *b++ = '\0';
      
      q = strpbrk(r, " \t");
      if (q != NULL)
	*q = '\0';
      q = strpbrk(g, " \t");
      if (q != NULL)
	*q = '\0';
      q = strpbrk(b, " \t");
      if (q != NULL)
	*q = '\0';
      
      q = strchr(p, '\0');
      while ((q != p) && ((q[-1] == ' ') || (q[-1] == '\t')))
	q--;
      *q = '\0';
      
      if (ptr == alloc)
	{
	  void* new;
	  size_t new_size = alloc ? (alloc << 1) : 4;
	  
	  new = realloc(rgammas, new_size * sizeof(*rgammas));
	  if (new == NULL)
	    goto fail;
	  rgammas = new;
	  
	  new = realloc(ggammas, new_size * sizeof(*ggammas));
	  if (new == NULL)
	    goto fail;
	  ggammas = new;
	  
	  new = realloc(bgammas, new_size * sizeof(*bgammas));
	  if (new == NULL)
	    goto fail;
	  bgammas = new;
	  
	  new = realloc(names, (new_size + 1) * sizeof(*names));
	  if (new == NULL)
	    goto fail;
	  names = new;
	  memset(names + alloc, 0, (new_size + 1 - alloc) * sizeof(*names));
	  
	  alloc = new_size;
	}
      
      if ((parse_double(rgammas + ptr, r) < 0) ||
	  (parse_double(ggammas + ptr, g) < 0) ||
	  (parse_double(bgammas + ptr, b) < 0))
	goto bad;
      names[ptr] = malloc(strlen(p) + 1);
      if (names[ptr] == NULL)
	goto fail;
      strcpy(names[ptr], p);
      ptr++;
      
      continue;
    bad:
      fprintf(stderr, "%s: ignoring malformatted line in %s: %zu\n", argv0, pathname, lineno);
    }
  
  if (fclose(f) < 0)
    {
      f = NULL;
      goto fail;
    }
  close(fd);
  free(line);
  return 0;
 fail:
  saved_errno = errno;
  free(line);
  if (f != NULL)
    fclose(f);
  if (fd >= 0)
    close(fd);
  errno = saved_errno;
  return -1;
}


/**
 * This function is called after the last
 * call to `handle_opt`
 * 
 * @param   argc  The number of unparsed arguments
 * @param   argv  `NULL` terminated list of unparsed arguments
 * @param   prio  The argument associated with the "-p" option
 * @return        Zero on success, -1 on error
 */
int handle_args(int argc, char* argv[], char* prio)
{
  int free_fflag = 0, saved_errno;
  int q = xflag + dflag;
  if ((q > 1) || (fflag && argc) || (xflag && ((fflag != NULL) || (argc > 0) || (prio != NULL))))
    usage();
  if (argc == 1)
    {
      if (parse_double(&rgamma, argv[0]) < 0)
	usage();
      bgamma = ggamma = rgamma;
    }
  else if (argc == 3)
    {
      if (parse_double(&rgamma, argv[0]) < 0)
	usage();
      if (parse_double(&ggamma, argv[1]) < 0)
	usage();
      if (parse_double(&bgamma, argv[2]) < 0)
	usage();
    }
  else if (argc)
    usage();
  if (!argc && !fflag && !xflag)
    {
      fflag = get_conf_file("gamma");
      if (fflag == NULL)
	return -1;
      free_fflag = 1;
    }
  if (fflag)
    if (parse_gamma_file(fflag) < 0)
      goto fail;
  if (free_fflag)
    free(fflag), fflag = NULL;
  return 0;
 fail:
  saved_errno = errno;
  if (free_fflag)
    free(fflag), fflag = NULL;
  errno = saved_errno;
  return cleanup(-1);
}


/**
 * Fill a filter
 * 
 * @param  filter  The filter to fill
 * @param  r       The red gamma
 * @param  g       The green gamma
 * @param  b       The blue gamma
 */
static void fill_filter(libcoopgamma_filter_t* restrict filter, double r, double g, double b)
{
  switch (filter->depth)
    {
#define X(CONST, MEMBER, MAX, TYPE)\
    case CONST:\
      libclut_gamma(&(filter->ramps.MEMBER), MAX, TYPE, r, g, b);\
      break;
LIST_DEPTHS
#undef X
    default:
      abort();
    }
}


/**
 * The main function for the program-specific code
 * 
 * @return  0: Success
 *          -1: Error, `errno` set
 *          -2: Error, `cg.error` set
 *          -3: Error, message already printed
 */
int start(void)
{
  int r;
  size_t i, j;
  
  if (xflag)
    for (i = 0; i < filters_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_REMOVE;
  else if (dflag)
    for (i = 0; i < filters_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_DEATH;
  else
    for (i = 0; i < filters_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_REMOVAL;
  
  if (!xflag && (names != NULL))
    if ((r = make_slaves()) < 0)
      return cleanup(r);
  
  if (names == NULL)
    for (i = 0, r = 1; i < filters_n; i++)
      {
	if (!(crtc_updates[i].master) || !(crtc_info[i].supported))
	  continue;
	if (!xflag)
	  fill_filter(&(crtc_updates[i].filter), rgamma, ggamma, bgamma);
	r = update_filter(i, 0);
	if ((r == -2) || ((r == -1) && (errno != EAGAIN)))
	  return cleanup(r);
	if (crtc_updates[i].slaves != NULL)
	  for (j = 0; crtc_updates[i].slaves[j] != 0; j++)
	    {
	      r = update_filter(crtc_updates[i].slaves[j], 0);
	      if ((r == -2) || ((r == -1) && (errno != EAGAIN)))
		return cleanup(r);
	    }
      }
  else
    for (i = 0, r = 1; i < filters_n; i++)
      {
	if (!(crtc_info[i].supported))
	  continue;
	for (j = 0; names[j] != NULL; j++)
	  if (!strcasecmp(crtc_updates[i].filter.crtc, names[j]))
	    {
	      fill_filter(&(crtc_updates[i].filter), rgammas[j], ggammas[j], bgammas[j]);
	      r = update_filter(i, 0);
	      if ((r == -2) || ((r == -1) && (errno != EAGAIN)))
		return cleanup(r);
	      break;
	    }
      }
  
  while (r != 1)
    if ((r = synchronise(-1)) < 0)
      return cleanup(r);
  
  if (!dflag)
    return cleanup(0);
  
  if (libcoopgamma_set_nonblocking(&cg, 0) < 0)
    return cleanup(-1);
  for (;;)
    if (libcoopgamma_synchronise(&cg, NULL, 0, &j) < 0)
      switch (errno)
	{
	case 0:
	  break;
	case ENOTRECOVERABLE:
	  goto enotrecoverable;
	default:
	  return cleanup(-1);
	}
  
 enotrecoverable:
  for (;;)
    if (pause() < 0)
      return cleanup(-1);
}