/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2016 - Daniel De Matteis
 * 
 *  RetroArch 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include <compat/posix_string.h>
#include <string/stdstring.h>

#include "command.h"
#include "general.h"
#include "msg_hash.h"
#include "system.h"

#include "audio/audio_driver.h"
#include "audio/audio_resampler_driver.h"
#include "camera/camera_driver.h"
#include "record/record_driver.h"
#include "location/location_driver.h"
#include "core.h"

#ifdef HAVE_MENU
#include "menu/menu_driver.h"
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#define HASH_LOCATION_DRIVER           0x09189689U
#define HASH_CAMERA_DRIVER             0xf25db959U
#define HASH_MENU_DRIVER               0xd607fb05U
#define HASH_INPUT_DRIVER              0x4c087840U
#define HASH_INPUT_JOYPAD_DRIVER       0xab124146U
#define HASH_VIDEO_DRIVER              0x1805a5e7U
#define HASH_AUDIO_DRIVER              0x26594002U
#define HASH_AUDIO_RESAMPLER_DRIVER    0xedcba9ecU
#define HASH_RECORD_DRIVER             0x144cd2cfU

/**
 * find_driver_nonempty:
 * @label              : string of driver type to be found.
 * @i                  : index of driver.
 * @str                : identifier name of the found driver
 *                       gets written to this string.
 * @len                : size of @str.
 *
 * Find driver based on @label.
 *
 * Returns: NULL if no driver based on @label found, otherwise
 * pointer to driver.
 **/
static const void *find_driver_nonempty(const char *label, int i,
      char *s, size_t len)
{
   const void *drv = NULL;
   uint32_t hash   = msg_hash_calculate(label);

   switch (hash)
   {
      case HASH_CAMERA_DRIVER:
         drv = camera_driver_find_handle(i);
         if (drv)
            strlcpy(s, camera_driver_find_ident(i), len);
         break;
      case HASH_LOCATION_DRIVER:
         drv = location_driver_find_handle(i);
         if (drv)
            strlcpy(s, location_driver_find_ident(i), len);
         break;
      case HASH_MENU_DRIVER:
#ifdef HAVE_MENU
         drv = menu_driver_find_handle(i);
         if (drv)
            strlcpy(s, menu_driver_find_ident(i), len);
#endif
         break;
      case HASH_INPUT_DRIVER:
         drv = input_driver_find_handle(i);
         if (drv)
            strlcpy(s, input_driver_find_ident(i), len);
         break;
      case HASH_INPUT_JOYPAD_DRIVER:
         drv = joypad_driver_find_handle(i);
         if (drv)
            strlcpy(s, joypad_driver_find_ident(i), len);
         break;
      case HASH_VIDEO_DRIVER:
         drv = video_driver_find_handle(i);
         if (drv)
            strlcpy(s, video_driver_find_ident(i), len);
         break;
      case HASH_AUDIO_DRIVER:
         drv = audio_driver_find_handle(i);
         if (drv)
            strlcpy(s, audio_driver_find_ident(i), len);
         break;
      case HASH_RECORD_DRIVER:
         drv = record_driver_find_handle(i);
         if (drv)
            strlcpy(s, record_driver_find_ident(i), len);
         break;
      case HASH_AUDIO_RESAMPLER_DRIVER:
         drv = audio_resampler_driver_find_handle(i);
         if (drv)
            strlcpy(s, audio_resampler_driver_find_ident(i), len);
         break;
   }

   return drv;
}

/**
 * driver_find_index:
 * @label              : string of driver type to be found.
 * @drv                : identifier of driver to be found.
 *
 * Find index of the driver, based on @label.
 *
 * Returns: -1 if no driver based on @label and @drv found, otherwise
 * index number of the driver found in the array.
 **/
static int driver_find_index(const char * label, const char *drv)
{
   unsigned i;
   char str[256] = {0};

   for (i = 0; 
         find_driver_nonempty(label, i, str, sizeof(str)) != NULL; i++)
   {
      if (string_is_empty(str))
         break;
      if (string_is_equal_noncase(drv, str))
         return i;
   }

   return -1;
}

static bool driver_find_first(const char *label, char *s, size_t len)
{
   find_driver_nonempty(label, 0, s, len);
   return true;
}

/**
 * driver_find_prev:
 * @label              : string of driver type to be found.
 * @s                  : identifier of driver to be found.
 * @len                : size of @s.
 *
 * Find previous driver in driver array.
 **/
static bool driver_find_prev(const char *label, char *s, size_t len)
{
   int i = driver_find_index(label, s);
   if (i > 0)
      find_driver_nonempty(label, i - 1, s, len);
   else
   {
      RARCH_WARN(
            "Couldn't find any previous driver (current one: \"%s\").\n", s);
      return false;
   }
   return true;
}

/**
 * driver_find_next:
 * @label              : string of driver type to be found.
 * @s                  : identifier of driver to be found.
 * @len                : size of @s.
 *
 * Find next driver in driver array.
 **/
bool driver_find_next(const char *label, char *s, size_t len)
{
   int i = driver_find_index(label, s);
   if (i >= 0 && !string_is_equal(s, "null"))
      find_driver_nonempty(label, i + 1, s, len);
   else
   {
      RARCH_WARN("%s (current one: \"%s\").\n",
            msg_hash_to_str(MSG_COULD_NOT_FIND_ANY_NEXT_DRIVER),
            s);
      return false;
   }
   return true;
}

static void driver_adjust_system_rates(void)
{
   audio_driver_monitor_adjust_system_rates();
   video_driver_monitor_adjust_system_rates();

   if (!video_driver_get_ptr(false))
      return;

   if (runloop_ctl(RUNLOOP_CTL_IS_NONBLOCK_FORCED, NULL))
      command_event(CMD_EVENT_VIDEO_SET_NONBLOCKING_STATE, NULL);
   else
      driver_ctl(RARCH_DRIVER_CTL_SET_NONBLOCK_STATE, NULL);
}

/**
 * driver_set_nonblock_state:
 *
 * Sets audio and video drivers to nonblock state (if enabled).
 *
 * If nonblock state is false, sets 
 * blocking state for both audio and video drivers instead.
 **/
static void driver_set_nonblock_state(void)
{
   bool                 enable = input_driver_is_nonblock_state();

   /* Only apply non-block-state for video if we're using vsync. */
   if (video_driver_is_active() && video_driver_get_ptr(false))
   {
      settings_t *settings = config_get_ptr();
      bool video_nonblock  = enable;

      if (     !settings->video.vsync 
            || runloop_ctl(RUNLOOP_CTL_IS_NONBLOCK_FORCED, NULL))
         video_nonblock = true;
      video_driver_set_nonblock_state(video_nonblock);
   }

   audio_driver_set_nonblocking_state(enable);
}

/**
 * driver_update_system_av_info:
 * @data               : pointer to new A/V info
 *
 * Update the system Audio/Video information. 
 * Will reinitialize audio/video drivers.
 * Used by RETRO_ENVIRONMENT_SET_SYSTEM_AV_INFO.
 *
 * Returns: true (1) if successful, otherwise false (0).
 **/
static bool driver_update_system_av_info(const struct retro_system_av_info *info)
{
   struct retro_system_av_info *av_info    = video_viewport_get_system_av_info();

   memcpy(av_info, info, sizeof(*av_info));
   command_event(CMD_EVENT_REINIT, NULL);

   /* Cannot continue recording with different parameters.
    * Take the easiest route out and just restart the recording. */
   if (recording_driver_get_data_ptr())
   {
      runloop_msg_queue_push(
            msg_hash_to_str(MSG_RESTARTING_RECORDING_DUE_TO_DRIVER_REINIT),
            2, 180, false);
      command_event(CMD_EVENT_RECORD_DEINIT, NULL);
      command_event(CMD_EVENT_RECORD_INIT, NULL);
   }

   return true;
}

#ifdef HAVE_MENU
/**
 * menu_update_libretro_info:
 *
 * Update menu state which depends on config.
 **/
static void menu_update_libretro_info(void)
{
   struct retro_system_info *info = NULL;
   
   menu_driver_ctl(RARCH_MENU_CTL_SYSTEM_INFO_GET,
         &info);
   
   if (!info)
      return;

   command_event(CMD_EVENT_CORE_INFO_INIT, NULL);
   command_event(CMD_EVENT_LOAD_CORE_PERSIST, NULL);
}
#endif

/**
 * init_drivers:
 * @flags              : Bitmask of drivers to initialize.
 *
 * Initializes drivers.
 * @flags determines which drivers get initialized.
 **/
static void init_drivers(int flags)
{
   if (flags & DRIVER_VIDEO)
      video_driver_unset_own_driver();
   if (flags & DRIVER_AUDIO)
      audio_driver_unset_own_driver();
   if (flags & DRIVER_INPUT)
      input_driver_unset_own_driver();
   if (flags & DRIVER_CAMERA)
      camera_driver_ctl(RARCH_CAMERA_CTL_UNSET_OWN_DRIVER, NULL);
   if (flags & DRIVER_LOCATION)
      location_driver_ctl(RARCH_LOCATION_CTL_UNSET_OWN_DRIVER, NULL);

#ifdef HAVE_MENU
   /* By default, we want the menu to persist through driver reinits. */
   menu_driver_ctl(RARCH_MENU_CTL_SET_OWN_DRIVER, NULL);
#endif

   if (flags & (DRIVER_VIDEO | DRIVER_AUDIO))
      driver_adjust_system_rates();

   if (flags & DRIVER_VIDEO)
   {
      struct retro_hw_render_callback *hwr =
         video_driver_get_hw_context();

      video_driver_monitor_reset();
      video_driver_init();

      if (!video_driver_is_video_cache_context_ack()
            && hwr->context_reset)
         hwr->context_reset();
      video_driver_unset_video_cache_context_ack();

      runloop_ctl(RUNLOOP_CTL_SET_FRAME_TIME_LAST, NULL);
   }

   if (flags & DRIVER_AUDIO)
   {
      audio_driver_init();
      audio_driver_new_devices_list();
   }

   /* Only initialize camera driver if we're ever going to use it. */
   if ((flags & DRIVER_CAMERA) && camera_driver_ctl(RARCH_CAMERA_CTL_IS_ACTIVE, NULL))
      camera_driver_ctl(RARCH_CAMERA_CTL_INIT, NULL);

   /* Only initialize location driver if we're ever going to use it. */
   if ((flags & DRIVER_LOCATION) && location_driver_ctl(RARCH_LOCATION_CTL_IS_ACTIVE, NULL))
      init_location();

#ifdef HAVE_MENU
   menu_update_libretro_info();

   if (flags & DRIVER_MENU)
   {
      menu_driver_ctl(RARCH_MENU_CTL_INIT, NULL);
      menu_driver_ctl(RARCH_MENU_CTL_CONTEXT_RESET, NULL);
   }
#endif

   if (flags & (DRIVER_VIDEO | DRIVER_AUDIO))
   {
      /* Keep non-throttled state as good as possible. */
      if (input_driver_is_nonblock_state())
         driver_ctl(RARCH_DRIVER_CTL_SET_NONBLOCK_STATE, NULL);
   }
}


/**
 * uninit_drivers:
 * @flags              : Bitmask of drivers to deinitialize.
 *
 * Deinitializes drivers.
 *
 *
 * @flags determines which drivers get deinitialized.
 **/

/**
 * Driver ownership - set this to true if the platform in question needs to 'own' 
 * the respective handle and therefore skip regular RetroArch 
 * driver teardown/reiniting procedure.
 *
 * If  to true, the 'free' function will get skipped. It is 
 * then up to the driver implementation to properly handle 
 * 'reiniting' inside the 'init' function and make sure it 
 * returns the existing handle instead of allocating and 
 * returning a pointer to a new handle.
 *
 * Typically, if a driver intends to make use of this, it should 
 * set this to true at the end of its 'init' function.
 **/
static void uninit_drivers(int flags)
{
#ifdef HAVE_MENU
   if (flags & DRIVER_MENU)
      menu_driver_ctl(RARCH_MENU_CTL_DEINIT, NULL);
#endif

   if ((flags & DRIVER_LOCATION) && !location_driver_ctl(RARCH_LOCATION_CTL_OWNS_DRIVER, NULL))
      location_driver_ctl(RARCH_LOCATION_CTL_DEINIT, NULL);

   if ((flags & DRIVER_CAMERA) && !camera_driver_ctl(RARCH_CAMERA_CTL_OWNS_DRIVER, NULL))
      camera_driver_ctl(RARCH_CAMERA_CTL_DEINIT, NULL);

   if (flags & DRIVER_AUDIO)
      audio_driver_deinit();

   if (flags & DRIVERS_VIDEO_INPUT)
      video_driver_deinit();

   if ((flags & DRIVER_VIDEO) && !video_driver_owns_driver())
      video_driver_destroy_data();

   if ((flags & DRIVER_INPUT) && !input_driver_owns_driver())
      input_driver_destroy_data();

   if ((flags & DRIVER_AUDIO) && !audio_driver_owns_driver())
      audio_driver_destroy_data();
}

bool driver_ctl(enum driver_ctl_state state, void *data)
{
   switch (state)
   {
      case RARCH_DRIVER_CTL_DEINIT:
         video_driver_destroy();
         audio_driver_destroy();
         input_driver_destroy();
#ifdef HAVE_MENU
         menu_driver_ctl(RARCH_MENU_CTL_DESTROY, NULL);
#endif
         location_driver_ctl(RARCH_LOCATION_CTL_DESTROY, NULL);
         camera_driver_ctl(RARCH_CAMERA_CTL_DESTROY, NULL);
         core_uninit_libretro_callbacks();
         break;
      case RARCH_DRIVER_CTL_UNINIT:
         {
            int *flags = (int*)data;
            if (!flags)
               return false;
            uninit_drivers(*flags);
         }
         break;
      case RARCH_DRIVER_CTL_UNINIT_ALL:
         {
            int flags = DRIVERS_CMD_ALL;
            return driver_ctl(RARCH_DRIVER_CTL_UNINIT, &flags);
         }
      case RARCH_DRIVER_CTL_INIT:
         {
            int *flags = (int*)data;
            if (!flags)
               return false;
            init_drivers(*flags);
         }
         break;
      case RARCH_DRIVER_CTL_INIT_ALL:
         {
            int flags = DRIVERS_CMD_ALL;
            return driver_ctl(RARCH_DRIVER_CTL_INIT, &flags);
         }
      case RARCH_DRIVER_CTL_INIT_PRE:
         audio_driver_find_driver();
         video_driver_find_driver();
         input_driver_find_driver();
         camera_driver_ctl(RARCH_CAMERA_CTL_FIND_DRIVER, NULL);
         find_location_driver();
#ifdef HAVE_MENU
         menu_driver_ctl(RARCH_MENU_CTL_FIND_DRIVER, NULL);
#endif
         break;
      case RARCH_DRIVER_CTL_SET_REFRESH_RATE:
         {
            float *hz = (float*)data;
            video_monitor_set_refresh_rate(*hz);
            audio_driver_monitor_set_rate();
            driver_adjust_system_rates();
         }
         break;
      case RARCH_DRIVER_CTL_SET_NONBLOCK_STATE:
         driver_set_nonblock_state();
         break;
      case RARCH_DRIVER_CTL_UPDATE_SYSTEM_AV_INFO:
         {
            const struct retro_system_av_info **info = (const struct retro_system_av_info**)data;
            if (info)
               return driver_update_system_av_info(*info);
         }
         return false;
      case RARCH_DRIVER_CTL_FIND_FIRST:
         {
            driver_ctx_info_t *drv = (driver_ctx_info_t*)data;
            if (!drv)
               return false;
            return driver_find_first(drv->label, drv->s, drv->len);
         }
      case RARCH_DRIVER_CTL_FIND_PREV:
         {
            driver_ctx_info_t *drv = (driver_ctx_info_t*)data;
            if (!drv)
               return false;
            return driver_find_prev(drv->label, drv->s, drv->len);
         }
      case RARCH_DRIVER_CTL_FIND_NEXT:
         {
            driver_ctx_info_t *drv = (driver_ctx_info_t*)data;
            if (!drv)
               return false;
            return driver_find_next(drv->label, drv->s, drv->len);
         }
      case RARCH_DRIVER_CTL_FIND_INDEX:
         {
            driver_ctx_info_t *drv = (driver_ctx_info_t*)data;
            if (!drv)
               return false;
            drv->len = driver_find_index(drv->label, drv->s);
         }
         break;
      case RARCH_DRIVER_CTL_NONE:
      default:
         break;
   }

   return true;
}