#include <SDL.h>
#include <string.h>

#include "lephisto.h"
#include "conf.h"
#include "log.h"
#include "physics.h"
#include "opengl.h"
#include "font.h"
#include "ship.h"
#include "pilot.h"
#include "player.h"
#include "input.h"
#include "joystick.h"
#include "space.h"
#include "rng.h"
#include "ai.h"
#include "outfit.h"
#include "pack.h"
#include "weapon.h"
#include "faction.h"
#include "xml.h"
#include "pause.h"
#include "toolkit.h"
#include "pilot.h"
#include "sound.h"
#include "spfx.h"
#include "music.h"

#define XML_START_ID    "Start"
#define START_DATA      "../dat/start.xml"

#define CONF_FILE       "conf"
#define VERSION_FILE    "VERSION"
#define VERSION_LEN     10
#define MINIMUM_FPS     0.5
#define FONT_SIZE       12
#define FONT_SIZE_SMALL 10

static int quit = 0; // Primary loop.
unsigned int gtime = 0; // Calculate FPS and movement.
static char version[VERSION_LEN];

// Just some default crap.
#define DATA_NAME_LEN 25  // Max length of data name.
char* data = NULL;
char dataname[DATA_NAME_LEN];
int nosound = 0;
int show_fps = 1; // Default - True.
int max_fps = 0;
int indjoystick = -1;
char* namjoystick = NULL;

// Prototypes.

static void display_fps(const double dt);
static void window_caption(void);
static void data_name(void);
// Update.
static void fps_control(void);
static void update_space(void);
static void render_space(void);

#ifdef WIN32
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow) {
  int argc = 0;
  char *argv[] = { NULL };
#else
int main(int argc, char** argv) {
#endif

  // Print the version.
  snprintf(version, VERSION_LEN, "%d.%d.%d", VMAJOR, VMINOR, VREV);
  LOG(" "APPNAME" v%s", version);

  // Initialize SDL for possible warnings.
  SDL_Init(0);
  
  // Input must be initialized for config to work.
  input_init();

  // Set the configuration.
  conf_setDefaults(); // Default config values.
  conf_loadConfig(CONF_FILE); // Have Lua parse config.
  conf_parseCLI(argc, argv); // Parse CLI arguments.

  // Load the data basics.
  data_name();
  LOG(" %s", dataname);
  DEBUG();
  
  // Random numbers.
  rng_init();

  if(gl_init()) {
    // Initializes video output.
    ERR("Initializing video output failed, exiting...");
    SDL_Quit();
    exit(EXIT_FAILURE);
  }

  // See if the data file is valid.
  if(pack_check(data)) {
    ERR("Data file '%s' not found", DATA);
    WARN("You can specify what data file you want to use with '-d'");
    WARN("See -h or -- help for more infoamtion.");
    SDL_Quit();
    exit(EXIT_FAILURE);
  }

  window_caption();

	// OpenAL sound.
	if(nosound)
		LOG("Sound is disabled!");
	else {
		if(sound_init()) WARN("Problem setting up sound!");
		music_load("Machina");
		music_play();
	}

  // Input.
  if((indjoystick >= 0) || (namjoystick != NULL)) {
    if(joystick_init())
      WARN("Error initializing joystick input");
    if(namjoystick != NULL) {
      // Use a joystick name to find joystick.
      if(joystick_use(joystick_get(namjoystick))) {
        WARN("Failure to open any joystick, falling back to default keybinds");
        input_setDefault();
      }
      free(namjoystick);
    }
    else if(indjoystick >= 0)
      // Must be using an id instead.
      if(joystick_use(indjoystick)) {
        WARN("Failure to open any joystick, falling back to default keybinds");
        input_setDefault();
      }
  }

  // Misc.
  if(ai_init())
    WARN("Error initializing AI");

  // Misc openGL init stuff.
  gl_fontInit(NULL, NULL, FONT_SIZE); // Init default font size.
  gl_fontInit(&gl_smallFont, NULL, FONT_SIZE_SMALL); // Small font.
  gui_init(); // Init the GUI crap.
  toolkit_init(); // Init the toolkit.

  // Data loading.
  factions_load();
	spfx_load();
  outfit_load();
  ships_load();
  fleet_load();
  space_load();

  // Create new player. TODO: Start menu.
  player_new();

  gtime = SDL_GetTicks(); // Init the time.

  // Main loop.
  SDL_Event event;
  // flushes the event loop, since I notices that when the joystick is loaded, it
  // creates button events that results in the player starting out accelerating.
  while(SDL_PollEvent(&event));
  while(!quit) {
    // Event loop.
    while(SDL_PollEvent(&event)) {
      if(event.type == SDL_QUIT) quit = 1; // Handle quit.

      // Pause the game if it is unfocused.
      if(event.type == SDL_ACTIVEEVENT) {
        if(event.active.state != SDL_APPMOUSEFOCUS) {
          // We don't need the mouse focus.
          if((event.active.gain == 0) && !paused) pause();
          else if((event.active.gain == 1) && paused) unpause();
        }
      }

      input_handle(&event); // handles all the events the player keybinds.
    }

		sound_update(); // Do the sound stuff.

    glClear(GL_COLOR_BUFFER_BIT);
    
    fps_control(); // Who doesn't love FPS control?
    if(!paused && !toolkit) update_space(); // Update the game.

    render_space();
    if(toolkit) toolkit_render();

    SDL_GL_SwapBuffers();
  }

  // Unload data.
  weapon_exit();  // Destroy all active weapons.
  space_exit();   // Clean up the universe!!!
  pilots_free();  // Free the pilots, they where locked up D:
  gui_free();     // Free up the gui.
  fleet_free();
  ships_free();
  outfit_free();
	spfx_free(); 		// Remove the special effects.
  factions_free();
  gl_freeFont(&gl_smallFont);

  gl_freeFont(NULL);

  // Exit subsystems.
  toolkit_exit();   // Kill the toolkit.
  ai_exit();        // Stop the Lua AI magicness.
  joystick_exit();  // Release joystick.
  input_exit();     // Clean up keybindings.
  gl_exit();        // Kills video output.
	sound_exit();			// Kills the sound.
	SDL_Quit();				// Quits SDL.
  
  // All is good.
  exit(EXIT_SUCCESS);
}

// Updates the game.
static double fps_dt = 1.;
static double dt = 0.;
static void fps_control(void) {
  // dt in ms/1000.
  dt = (double)(SDL_GetTicks() - gtime) / 1000.;
  gtime = SDL_GetTicks();

  if(paused) SDL_Delay(10); // Drop paused FPS to be nice to the CPU.
  
  // If the fps is limited..
  if((max_fps != 0) && (dt < 1./max_fps)) {
    double delay = 1./max_fps - dt;
    SDL_Delay(delay);
    fps_dt += delay; // Make sure it displays the propper FPS.
  }
}

// Update the game.
static void update_space(void) {
  weapons_update(dt);
	spfx_update(dt);
  pilots_update(dt);
}

// == Renders the game. ==================================
// Blitting order. (layers)
//
//    BG  | Stars and planets.
//        | Background player stuff (planet targetting)
//        | Background particles.
//        | Back layer weapons.
//        X
//    N   | NPC ships.
//        | Front layer weapons.
//        | Normal layer particles (above ships).
//        X
//    FG  | Player.
//        | Foreground particles.
//        | Text and GUI.
// ========================================================
static void render_space(void) {
  // BG.
  space_render(dt);
  planets_render();
  player_renderBG();
  weapons_render(WEAPON_LAYER_BG);
  // N.
  pilots_render();
  weapons_render(WEAPON_LAYER_FG);
	spfx_render(SPFX_LAYER_BACK);
  // FG.  
  player_render();
	spfx_render(SPFX_LAYER_FRONT);
  display_fps(dt);
}


// Spit this out on display.
static double fps = 0.;
static double fps_cur = 0.;
static void display_fps(const double dt) {
  double x, y;
  fps_dt += dt;
  fps_cur += 1.;
  if(fps_dt > 1.) {
    // Recalculate every second.
    fps = fps_cur / fps_dt;
    fps_dt = fps_cur = 0.;
  }

  x = 10.;
  y = (double)(gl_screen.h - 20);
  if(show_fps)
    gl_print(NULL, x, y, NULL, "%3.2f", fps);
}

static void data_name(void) {
  uint32_t bufsize;
  char* buf;
  
  // Check if data file is valid.
  if(pack_check(DATA)) {
    ERR("Data file '%s' not found", data);
    WARN("You should specify which data file to use with '-d'");
    WARN("See -h or --help for more information");
    SDL_Quit();
    exit(EXIT_FAILURE);
  }

  // Check the version.
  buf = pack_readfile(DATA, VERSION_FILE, &bufsize);

  if(strncmp(buf, version, bufsize) != 0) {
    WARN("Lephisto version and data module version differ!");
    WARN("Lephisto is v%s, data is for v%s", version, buf);
  }

  free(buf);

  // Load the datafiles name.
  buf = pack_readfile(DATA, START_DATA, &bufsize);

  xmlNodePtr node;
  xmlDocPtr doc = xmlParseMemory(buf, bufsize);

  node = doc->xmlChildrenNode;
  if(!xml_isNode(node, XML_START_ID)) {
    ERR("Maformed '"START_DATA"' file: missing root element '"XML_START_ID"'");
    return;
  }

  node = node->xmlChildrenNode; // First node.
  if(node == NULL) {
    ERR("Malformed '"START_DATA"' file: does not contain elements");
    return;
  }
  do {
    if(xml_isNode(node, "name"))
      strncpy(dataname, xml_get(node), DATA_NAME_LEN);
  } while((node = node->next));

  xmlFreeDoc(doc);
  free(buf);
  xmlCleanupParser();
}

static void window_caption(void) {
  char tmp[DATA_NAME_LEN+10];

  snprintf(tmp, DATA_NAME_LEN+10, APPNAME" - %s", dataname);
  SDL_WM_SetCaption(tmp, NULL);
}