/**
 * 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 <libcoopgamma.h>



/**
 * Information (except asynchronous call context)
 * required to update the gamma ramps on a CRTC.
 */
typedef struct filter_update
{
  /**
   * The filter to update
   * 
   * `.filter.crtc`, `.filter.class`, and
   * `.filter.priority`, `.filter.depth`
   * are preconfigured, and `.filter.ramps`
   * is preinitialised.
   */
  libcoopgamma_filter_t filter;
  
  /**
   * Has the update been synchronised?
   */
  int synced;
  
  /**
   * Did the update fail?
   */
  int failed;
  
  /**
   * Error description if `.failed` is true
   */
  libcoopgamma_error_t error;
  
  /**
   * If zero, the ramps in `.filter` shall
   * neither be modified nor freed.
   */
  int master;
  
  /**
   * 0-terminated list of elements in
   * `.crtc_updates` which shares gamma
   * ramps with this instance
   * 
   * This will only be set if `.master`
   * is true.
   */
  size_t* slaves;
  
} filter_update_t;



/**
 * The process's name
 */
extern const char* argv0;

/**
 * The libcoopgamma context
 */
extern libcoopgamma_context_t cg;

/**
 * The names of the selected CRTC:s
 */
extern char** crtcs;

/**
 * Gamma ramp updates for each CRTC
 */
extern filter_update_t* crtc_updates;

/**
 * CRTC and monitor information about
 * each selected CRTC and connect monitor
 */
extern libcoopgamma_crtc_info_t* crtc_info;

/**
 * The number of selected CRTC:s
 */
extern size_t crtcs_n;



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

/**
 * The default class for the program
 */
extern char* const default_class;



/**
 * Make elements in `crtc_updates` slaves where appropriate
 * 
 * @return  Zero on success, -1 on error
 */
int make_slaves(void);

/**
 * Update a filter and synchronise calls
 * 
 * @param   index    The index of the CRTC
 * @param   timeout  The number of milliseconds a call to `poll` may block,
 *                   -1 if it may block forever
 * @return           1: Success, no pending synchronisations
 *                   0: Success, with still pending synchronisations
 *                   -1: Error, `errno` set
 *                   -2: Error, `cg.error` set
 * 
 * @throws  EINTR   Call to `poll` was interrupted by a signal
 * @throws  EAGAIN  Call to `poll` timed out
 */
int update_filter(size_t index, int timeout);

/**
 * Synchronised calls
 * 
 * @param   timeout  The number of milliseconds a call to `poll` may block,
 *                   -1 if it may block forever
 * @return           1: Success, no pending synchronisations
 *                   0: Success, with still pending synchronisations
 *                   -1: Error, `errno` set
 *                   -2: Error, `cg.error` set
 * 
 * @throws  EINTR   Call to `poll` was interrupted by a signal
 * @throws  EAGAIN  Call to `poll` timed out
 */
int synchronise(int timeout);


/**
 * Print usage information and exit
 */
#if defined(__GNUC__)
__attribute__((__noreturn__))
#endif
extern void usage(void);

/**
 * 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
 */
#if defined(__GNUC__)
__attribute__((__nonnull__(1)))
#endif
extern int handle_opt(char* opt, char* arg);

/**
 * 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
 */
#if defined(__GNUC__)
__attribute__((__nonnull__(2)))
#endif
extern int handle_args(int argc, char* argv[], char* method, char* site, char** crtcs,
		       char* prio, char* rule);

/**
 * 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
 */
extern int start(void);