/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   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 2, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Patrick Boenzli
   co-programmer: ...
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_LOAD

#include "game_loader.h"

#include "shell_command.h"
#include "campaign.h"
#include "world.h"
#include "orxonox.h"
#include "camera.h"
#include "vector.h"
#include "resource_manager.h"
#include "factory.h"
#include "event.h"
#include "event_handler.h"
#include <string.h>


using namespace std;


SHELL_COMMAND(quit, GameLoader, stop)
    ->describe("quits the game")
    ->setAlias("orxoquit");


GameLoader* GameLoader::singletonRef = NULL;


/**
 *  simple constructor
*/
GameLoader::GameLoader ()
{
  this->setClassID(CL_GAME_LOADER, "GameLoader");
  this->setName("GameLoader");

}


/**
 *  simple deconstructor
*/
GameLoader::~GameLoader ()
{
  if( this->currentCampaign)
    delete this->currentCampaign;
  this->currentCampaign = NULL;
}


/**
 *  this class is a singleton class
 * @returns an instance of itself

   if you are unsure about singleton classes, check the theory out on the internet :)
*/
GameLoader* GameLoader::getInstance()
{
  if(singletonRef == NULL)
    singletonRef = new GameLoader();
  return singletonRef;
}

/**
 *  initializes the GameLoader
*/
ErrorMessage GameLoader::init()
{
  if(this->currentCampaign != NULL)
    this->currentCampaign->init();

  this->eventHandler = EventHandler::getInstance();
  this->eventHandler->subscribe(this, ES_GAME, KeyMapper::PEV_PAUSE);
  this->eventHandler->subscribe(this, ES_ALL, EV_MAIN_QUIT);          //< External Quit Event
  this->eventHandler->subscribe(this, ES_ALL, KeyMapper::PEV_QUIT);
  this->eventHandler->subscribe(this, ES_GAME, KeyMapper::PEV_NEXT_WORLD);
  this->eventHandler->subscribe(this, ES_GAME, KeyMapper::PEV_PREVIOUS_WORLD);
}


/**
 *  reads a campaign definition file into a campaign class
 * @param fileName to be loaded
 * @returns the loaded campaign

   this will interprete the map/campaign files and recursivly load a tree of worlds/campaigns
*/
ErrorMessage GameLoader::loadCampaign(const char* fileName)
{
  ErrorMessage errorCode;
  char* campaignName = ResourceManager::getFullName(fileName);
  if (campaignName)
    {
      this->currentCampaign = this->fileToCampaign(campaignName);
      delete[] campaignName;
    }
//   World* world0 = new World(DEBUG_WORLD_0);
//   world0->setNextStoryID(WORLD_ID_GAMEEND);
//   this->currentCampaign->addEntity(world0, WORLD_ID_2);
}

/**
 *  loads a debug campaign for test purposes only.
 * @param campaignID the identifier of the campaign.
 * @returns error message if not able to do so.
*/
ErrorMessage GameLoader::loadDebugCampaign(Uint32 campaignID)
{
  switch(campaignID)
    {
      /*
         Debug Level 0: Debug level used to test the base frame work.
         As you can see, all storyentity data is allocated before game
         start. the storyentity will load themselfs shortly before start
         through the StoryEntity::init() funtion.
      */
    case DEBUG_CAMPAIGN_0:
      {
        Campaign* debugCampaign = new Campaign();

        World* world0 = new World(DEBUG_WORLD_0);
        world0->setNextStoryID(WORLD_ID_1);
        debugCampaign->addEntity(world0, WORLD_ID_0);

        World* world1 = new World(DEBUG_WORLD_1);
        world1->setNextStoryID(WORLD_ID_2);
        debugCampaign->addEntity(world1, WORLD_ID_1);

        World* world2 = new World(DEBUG_WORLD_2);
        world2->setNextStoryID(WORLD_ID_GAMEEND);
        debugCampaign->addEntity(world2, WORLD_ID_2);

        this->currentCampaign = debugCampaign;
        break;
      }
    }
}


/**
  *  starts the current entity
  * @returns error code if this action has caused a error
*/
ErrorMessage GameLoader::start()
{
  if(this->currentCampaign != NULL)
    this->currentCampaign->start();
}


/**
  *  stops the current entity
  * @returns error code if this action has caused a error

    ATTENTION: this function shouldn't call other functions, or if so, they must return
    after finishing. If you ignore or forget to do so, the current entity is not able to
    terminate and it will run in the background or the ressources can't be freed or even
    worse: are freed and the program will end in a segmentation fault!
    hehehe, have ya seen it... :)
*/
void GameLoader::stop()
{
  if(this->currentCampaign != NULL)
    this->currentCampaign->stop();
}


/**
  *  pause the current entity
  * @returns error code if this action has caused a error

    this pauses the current entity or passes this call forth to the running entity.
*/
ErrorMessage GameLoader::pause()
{
  this->isPaused = true;
  if(this->currentCampaign != NULL)
    this->currentCampaign->pause();
}


/**
  *  resumes a pause
  * @returns error code if this action has caused a error

    this resumess the current entity or passes this call forth to the running entity.
*/
ErrorMessage GameLoader::resume()
{
  this->isPaused = false;
  if(this->currentCampaign != NULL)
    this->currentCampaign->resume();
}


/**
 *  release the mem ATTENTION: not implemented
 */
ErrorMessage GameLoader::destroy()
{

}


/**
 *  reads a campaign definition file into a campaign class
 * @param fileName to be loaded
 * @returns the loaded campaign

   this will interprete the map/campaign files and recursivly load a tree of worlds/campaigns
*/
Campaign* GameLoader::fileToCampaign(const char* fileName)
{
  /* do not entirely load the campaign. just the current world
     before start of each world, it has to be initialized so it
     can load everything it needs into memory then.
  */

  if( fileName == NULL)
    {
      PRINTF(2)("No filename specified for loading");
      return NULL;
    }

  TiXmlDocument* XMLDoc = new TiXmlDocument( fileName);
  // load the campaign document
  if( !XMLDoc->LoadFile())
    {
      // report an error
      PRINTF(1)("Could not load XML File %s: %s @ %d:%d\n", fileName, XMLDoc->ErrorDesc(), XMLDoc->ErrorRow(), XMLDoc->ErrorCol());
      delete XMLDoc;
      return NULL;
    }

  // check basic validity
  TiXmlElement* root = XMLDoc->RootElement();
  assert( root != NULL);

  if( strcmp( root->Value(), "Campaign"))
    {
      // report an error
      PRINTF(2)("Specified XML File is not an orxonox campaign file (Campaign element missing)\n");
      delete XMLDoc;
      return NULL;
    }

  // construct campaign
  Campaign* c = new Campaign( root);

  // free the XML data
  delete XMLDoc;

  return c;
}


/**
 *  handle keyboard commands
 * @param event the event to handle
 */
void GameLoader::process(const Event& event)
{
  if( event.type == KeyMapper::PEV_NEXT_WORLD)
  {
    if( likely(event.bPressed))
    {
      this->nextLevel();
    }
  }
  else if( event.type == KeyMapper::PEV_PREVIOUS_WORLD)
  {
    if( likely(event.bPressed))
    {
      this->previousLevel();
    }
  }
  else if( event.type == KeyMapper::PEV_PAUSE)
  {
    if( likely(event.bPressed))
    {
      if(this->isPaused)
        this->resume();
      else
        this->pause();
    }
  }
  else if( event.type == KeyMapper::PEV_QUIT)
  {
    if( event.bPressed) this->stop();
  }
  else if (event.type == EV_MAIN_QUIT)
    this->stop();
}


/**
  \brief this changes to the next level
*/
void GameLoader::nextLevel()
{
  if(this->currentCampaign != NULL)
    this->currentCampaign->nextLevel();
}


/**
  \brief change to the previous level - not implemented

  this propably useless
*/
void GameLoader::previousLevel()
{
  if(this->currentCampaign != NULL)
    this->currentCampaign->previousLevel();
}