/**
 * 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/>.
 */
#define _DEFAULT_SOURCE
#define _BSD_SOURCE

#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 = -(((int64_t)1) << 62);

/**
 * The default class for the program
 */
char* const default_class = PKGNAME "::cg-limits::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;

/**
 * -B: brightness listing file
 */
static char* Bflag = NULL;

/**
 * -C: constrat listing file
 */
static char* Cflag = NULL;

/**
 * The brightness of the red channel
 */
static double rbrightness = 0;

/**
 * The brightness of the green channel
 */
static double gbrightness = 0;

/**
 * The brightness of the blue channel
 */
static double bbrightness = 0;

/**
 * The contrast of the red channel
 */
static double rcontrast = 1;

/**
 * The contrast of the green channel
 */
static double gcontrast = 1;

/**
 * The contrast of the blue channel
 */
static double bcontrast = 1;

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

/**
 * The brightness of the red channel on monitor
 * with same index in `brightness_names`
 */
static double* rbrightnesses = NULL;

/**
 * The brightness of the green channel on monitor
 * with same index in `brightness_names`
 */
static double* gbrightnesses = NULL;

/**
 * The brightness of the blue channel on monitor
 * with same index in `brightness_names`
 */
static double* bbrightnesses = NULL;

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

/**
 * The contrast of the red channel on monitor
 * with same index in `contrast_names`
 */
static double* rcontrasts = NULL;

/**
 * The contrast of the green channel on monitor
 * with same index in `contrast_names`
 */
static double* gcontrasts = NULL;

/**
 * The contrast of the blue channel on monitor
 * with same index in `contrast_names`
 */
static double* bcontrasts = 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] "
	  "([-B brigtness-file] [-C contrast-file] | brightness-all:contrast-all | "
	  "brightness-red:contrast-red brightness-green:contrast-green brightness-blue:contrast-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 (brightness_names != NULL)
    {
      char** p = brightness_names;
      while (*p)
	free(*p++);
    }
  free(brightness_names);
  free(rbrightnesses);
  free(gbrightnesses);
  free(bbrightnesses);
  if (contrast_names != NULL)
    {
      char** p = contrast_names;
      while (*p)
	free(*p++);
    }
  free(contrast_names);
  free(rcontrasts);
  free(gcontrasts);
  free(bcontrasts);
  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 'B':
	if (Bflag || !(Bflag = arg))
	  usage();
	return 1;
      case 'C':
	if (Cflag || !(Cflag = 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 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 || isinf(*out) || isnan(*out) || *end)
    return -1;
  if (!strchr("-0123456789.", *str))
    return -1;
  return 0;
}


/**
 * Parse two doubles encoded as a "%lf:%lf" string
 * 
 * @param   left   Output parameter for the first value
 * @param   right  Output parameter for the second value
 * @param   str    The string
 * @retunr         Zero on success, -1 if the string is invalid
 */
static int parse_twidouble(double* restrict left, double* restrict right, const char* restrict str)
{
  char* p = strchr(str, ':');
  int r;
  if (p == NULL)
    return -1;
  *p = '\0';
  r = -((parse_double(left, str) < 0) || (parse_double(right, p + 1) < 0));
  *p = ':';
  return r;
}


/**
 * Parse configuration file
 * 
 * @param   pathname  The pathname of the file
 * @param   names     Reference to the list of names
 * @param   rs        Reference to the list of red values
 * @param   gs        Reference to the list of green values
 * @param   bs        Reference to the list of blue values
 * @return            Zero on success, -1 on error
 */
static int parse_conf_file(const char* restrict pathname, char*** restrict names,
			   double** restrict rs, double** restrict gs, double** restrict bs)
{
  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(*rs, new_size * sizeof(**rs));
	  if (new == NULL)
	    goto fail;
	  *rs = new;
	  
	  new = realloc(*gs, new_size * sizeof(**gs));
	  if (new == NULL)
	    goto fail;
	  *gs = new;
	  
	  new = realloc(*bs, new_size * sizeof(**bs));
	  if (new == NULL)
	    goto fail;
	  *bs = 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((*rs) + ptr, r) < 0) ||
	  (parse_double((*gs) + ptr, g) < 0) ||
	  (parse_double((*bs) + 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;
}


/**
 * Parse brightness configuration file
 * 
 * @param   pathname  The pathname of the file
 * @return            Zero on success, -1 on error
 */
static int parse_brightness_file(const char* restrict pathname)
{
  return parse_conf_file(pathname, &brightness_names, &rbrightnesses, &gbrightnesses, &bbrightnesses);
}


/**
 * Parse contrast configuration file
 * 
 * @param   pathname  The pathname of the file
 * @return            Zero on success, -1 on error
 */
static int parse_contrast_file(const char* restrict pathname)
{
  return parse_conf_file(pathname, &contrast_names, &rcontrasts, &gcontrasts, &bcontrasts);
}


/**
 * 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   method  The argument associated with the "-M" option
 * @param   site    The argument associated with the "-S" option
 * @param   crtcs   The arguments associated with the "-c" options, `NULL`-terminated
 * @param   prio    The argument associated with the "-p" option
 * @param   rule    The argument associated with the "-R" option
 * @return          Zero on success, -1 on error
 */
int handle_args(int argc, char* argv[], char* method, char* site,
		char** crtcs, char* prio, char* rule)
{
  int free_Bflag = 0, free_Cflag = 0, saved_errno;
  int q = xflag + dflag;
  q += (method != NULL) &&  !strcmp(method, "?");
  q += (prio   != NULL) &&  !strcmp(prio, "?");
  q += (rule   != NULL) && (!strcmp(rule, "?") || !strcmp(rule, "??"));
  for (; *crtcs; crtcs++)
    q += !strcmp(*crtcs, "?");
  if ((q > 1) || (xflag && ((Bflag != NULL) || (Cflag != NULL) || (argc > 0) || (prio != NULL))))
    usage();
  if ((Bflag || Cflag) && argc)
    usage();
  
  if (argc == 1)
    {
      if (parse_twidouble(&rbrightness, &rcontrast, argv[0]) < 0)
	usage();
      bbrightness = gbrightness = rbrightness;
      bcontrast = gcontrast = rcontrast;
    }
  else if (argc == 3)
    {
      if (parse_twidouble(&rbrightness, &rcontrast, argv[0]) < 0)
	usage();
      if (parse_twidouble(&gbrightness, &gcontrast, argv[1]) < 0)
	usage();
      if (parse_twidouble(&bbrightness, &bcontrast, argv[2]) < 0)
	usage();
    }
  else if (argc)
    usage();
  
  if (!argc && !Bflag && !xflag)
    {
      Bflag = get_conf_file("brightness");
      if (Bflag == NULL)
	return -1;
      free_Bflag = 1;
    }
  if (Bflag)
    if (parse_brightness_file(Bflag) < 0)
      goto fail;
  if (free_Bflag)
    free(Bflag), Bflag = NULL;
  
  if (!argc && !Cflag && !xflag)
    {
      Cflag = get_conf_file("contrast");
      if (Cflag == NULL)
	return -1;
      free_Cflag = 1;
    }
  if (Cflag)
    if (parse_contrast_file(Cflag) < 0)
      goto fail;
  if (free_Cflag)
    free(Cflag), Cflag = NULL;
  
  return 0;
 fail:
  saved_errno = errno;
  if (free_Bflag)
    free(Bflag), Bflag = NULL;
  if (free_Cflag)
    free(Cflag), Cflag = NULL;
  errno = saved_errno;
  return cleanup(-1);
}


/**
 * Fill a filter
 * 
 * @param   filter  The filter to fill
 * @param   rb      The red brightness
 * @param   rc      The red contrast
 * @param   gb      The green brightness
 * @param   gc      The green contrast
 * @param   bb      The blue brightness
 * @param   bc      The blue contrast
 * @return          Zero on success, -1 on error
 */
static int fill_filter(libcoopgamma_filter_t* restrict filter,
		       double rb, double rc, double gb, double gc, double bb, double bc)
{
  union libcoopgamma_ramps dramps;
  size_t size;
  
  if (filter->depth == LIBCOOPGAMMA_DOUBLE)
    {
      libclut_rgb_limits(&(filter->ramps.d), (double)1, double, rb, rc, gb, gc, bb, bc);
      libclut_clip(&(filter->ramps.d), (double)1, double, 1, 1, 1);
      return 0;
    }
  if (filter->depth == LIBCOOPGAMMA_FLOAT)
    {
      libclut_rgb_limits(&(filter->ramps.f), (float)1, float, rb, rc, gb, gc, bb, bc);
      libclut_clip(&(filter->ramps.f), (float)1, float, 1, 1, 1);
      return 0;
    }  
  
  size  = dramps.d.red_size   = filter->ramps.d.red_size;
  size += dramps.d.green_size = filter->ramps.d.green_size;
  size += dramps.d.blue_size  = filter->ramps.d.blue_size;
  dramps.d.red = calloc(size, sizeof(double));
  if (dramps.d.red == NULL)
    return -1;
  dramps.d.green = dramps.d.red   + dramps.d.red_size;
  dramps.d.blue  = dramps.d.green + dramps.d.green_size;
  
  libclut_start_over(&(dramps.d), (double)1, double, 1, 1, 1);
  libclut_rgb_limits(&(dramps.d), (double)1, double, rb, rc, gb, gc, bb, bc);
  libclut_clip(&(dramps.d), (double)1, double, 1, 1, 1);
  
  switch (filter->depth)
    {
    case LIBCOOPGAMMA_UINT8:
      libclut_translate(&(filter->ramps.u8), UINT8_MAX, uint8_t, &(dramps.d), (double)1, double);
      break;
    case LIBCOOPGAMMA_UINT16:
      libclut_translate(&(filter->ramps.u16), UINT16_MAX, uint16_t, &(dramps.d), (double)1, double);
      break;
    case LIBCOOPGAMMA_UINT32:
      libclut_translate(&(filter->ramps.u32), UINT32_MAX, uint32_t, &(dramps.d), (double)1, double);
      break;
    case LIBCOOPGAMMA_UINT64:
      libclut_translate(&(filter->ramps.u64), UINT64_MAX, uint64_t, &(dramps.d), (double)1, double);
      break;
    default:
      abort();
    }
  
  free(dramps.d.red);
  return 0;
}


/**
 * 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, k;
  
  if (xflag)
    for (i = 0; i < crtcs_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_REMOVE;
  else if (dflag)
    for (i = 0; i < crtcs_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_DEATH;
  else
    for (i = 0; i < crtcs_n; i++)
      crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_REMOVAL;
  
  if (!xflag && ((brightness_names != NULL) || (contrast_names != NULL)))
    if ((r = make_slaves()) < 0)
      return cleanup(r);
  
  if ((brightness_names == NULL) && (contrast_names == NULL))
    for (i = 0, r = 1; i < crtcs_n; i++)
      {
	if (!(crtc_updates[i].master) || !(crtc_info[i].supported))
	  continue;
	if (!xflag)
	  if ((r = fill_filter(&(crtc_updates[i].filter), rbrightness, rcontrast,
			       gbrightness, gcontrast, bbrightness, bcontrast)) < 0)
	    return cleanup(r);
	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
    {
      char* empty = NULL;
      char** bnames = brightness_names ? brightness_names : &empty;
      char** cnames = contrast_names ? contrast_names : &empty;
      for (i = 0, r = 1; i < crtcs_n; i++)
	{
	  if (!(crtc_info[i].supported))
	    continue;
	  for (j = 0; bnames[j] != NULL; j++)
	    if (!strcasecmp(crtc_updates[i].filter.crtc, bnames[j]))
	      break;
	  for (k = 0; cnames[k] != NULL; k++)
	    if (!strcasecmp(crtc_updates[k].filter.crtc, cnames[k]))
	      break;
	  if ((bnames[j] != NULL) || (cnames[k] != NULL))
	    {
	      double rb = 0, gb = 0, bb = 0, rc = 1, bc = 1, gc = 1;
	      if (bnames[j] != NULL)
		rb = rbrightnesses[j], gb = gbrightnesses[j], bb = bbrightnesses[j];
	      if (cnames[j] != NULL)
		rc = rcontrasts[j], gc = gcontrasts[j], bc = bcontrasts[j];
	      if ((r = fill_filter(&(crtc_updates[i].filter), rb, rc, gb, gc, bb, bc)) < 0)
		return cleanup(r);
	      r = update_filter(i, 0);
	      if ((r == -2) || ((r == -1) && (errno != EAGAIN)))
		return cleanup(r);
	    }
	}
    }
  
  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);
}