/*
   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: Benjamin Grauer
   co-programmer: ...
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_GRAPHICS

#include "light.h"

#include "glincl.h"
#include "vector.h"
#include "tinyxml.h"
#include "load_param.h"
#include "factory.h"
#include "debug.h"

using namespace std;

CREATE_FACTORY(Light);

//! Definition of the Lights and their Names
int lightsV[] =
{
                  GL_LIGHT0,
                  GL_LIGHT1,
                  GL_LIGHT2,
                  GL_LIGHT3,
                  GL_LIGHT4,
                  GL_LIGHT5,
                  GL_LIGHT6,
                  GL_LIGHT7
};

/**
 * @param root The XML-element to load the Light from

  @todo what to do, if no Light-Slots are open anymore ???
 */
 Light::Light(const TiXmlElement* root)
{
  PRINTF(4)("initializing Light number %d.\n", this->lightNumber);

  this->lightNumber = LightManager::getInstance()->registerLight(this);

  this->setClassID(CL_LIGHT, "Light");
  char tmpName[10];
  sprintf(tmpName, "Light[%d]", this->lightNumber);
  this->setName(tmpName);

  // enable The light
  glEnable(lightsV[this->lightNumber]); // postSpawn

  // set values (defaults)
  this->setDiffuseColor(1.0, 1.0, 1.0);
  this->setSpecularColor(1.0, 1.0, 1.0);

  if (root != NULL)
    this->loadParams(root);
}

/**
 *  destroys a Light
*/
Light::~Light()
{
  glDisable(lightsV[this->lightNumber]);

  LightManager::getInstance()->unregisterLight(this);
}

/**
 * @param root The XML-element to load the Light from
 */
void Light::loadParams(const TiXmlElement* root)
{
  static_cast<PNode*>(this)->loadParams(root);

  LoadParam(root, "diffuse-color", this, Light, setDiffuseColor)
      .describe("sets the diffuse color of the Light (red [0-1], green [0-1], blue [0-1])");

  LoadParam(root, "specular-color", this, Light, setSpecularColor)
      .describe("sets the specular color of the Light (red [0-1], green [0-1], blue [0-1])");

  LoadParam(root, "attenuation", this, Light, setAttenuation)
      .describe("sets the Attenuation of the LightSource (constant Factor, linear Factor, quadratic Factor).");

  LoadParam(root, "spot-direction", this, Light, setSpotDirection)
      .describe("sets the Direction of the Spot");

  LoadParam(root, "spot-cutoff", this, Light, setSpotCutoff)
      .describe("the cuttoff of the Spotlight");
}

/**
 *  sets an emitting Diffuse color of this Light
 * @param r red
 * @param g green
 * @param b blue
*/
void Light::setDiffuseColor(GLfloat r, GLfloat g, GLfloat b)
{
  this->diffuseColor[0] = r;
  this->diffuseColor[1] = g;
  this->diffuseColor[2] = b;
  this->diffuseColor[3] = 1.0;

  glLightfv (lightsV[this->lightNumber], GL_DIFFUSE, this->diffuseColor);
}

/**
 *  sets an emitting Specular color of this Light
 * @param r red
 * @param g green
 * @param b blue
*/
void Light::setSpecularColor(GLfloat r, GLfloat g, GLfloat b)
{
  this->specularColor[0] = r;
  this->specularColor[1] = g;
  this->specularColor[2] = b;
  this->specularColor[3] = 1.0;

  glLightfv (lightsV[this->lightNumber], GL_SPECULAR, this->specularColor);
}


/**
 *  Sets the AttenuationType of this Light Source
 * @param constantAttenuation The Constant Attenuation of the Light
 * @param linearAttenuation The Linear Attenuation of the Light
 * @param quadraticAttenuation The Quadratic Attenuation of the Light
*/
void Light::setAttenuation(float constantAttenuation, float linearAttenuation, float quadraticAttenuation)
{
  this->constantAttenuation  = constantAttenuation;
  this->linearAttenuation    = linearAttenuation;
  this->quadraticAttenuation = quadraticAttenuation;

  glLightf(lightsV[this->lightNumber], GL_CONSTANT_ATTENUATION,  constantAttenuation);
  glLightf(lightsV[this->lightNumber], GL_LINEAR_ATTENUATION,    linearAttenuation);
  glLightf(lightsV[this->lightNumber], GL_QUADRATIC_ATTENUATION, quadraticAttenuation);
}


/**
 *  stets the direction of the Spot Light.
 * @param direction The direction of the Spot Light.
*/
void Light::setSpotDirection(const Vector& direction)
{
  this->spotDirection[0] = direction.x;
  this->spotDirection[1] = direction.y;
  this->spotDirection[2] = direction.z;

  glLightfv(lightsV[this->lightNumber], GL_SPOT_DIRECTION, this->spotDirection);
}


/**
 *  sets the cutoff angle of the Light.
 * @param cutoff The cutoff angle.
*/
void Light::setSpotCutoff(GLfloat cutoff)
{
  this->spotCutoff = cutoff;
  glLightf(lightsV[this->lightNumber], GL_SPOT_CUTOFF, cutoff);
}

/**
 *  draws this Light. Being a World-entity the possibility to do this lies at hand.
*/
void Light::draw() const
{
  float pos[4] = {this->getAbsCoor().x, this->getAbsCoor().y, this->getAbsCoor().z, 1.0};
  PRINTF(4)("Drawing The Lights new Position at %f %f %f\n", pos[0], pos[1], pos[2]);
  glLightfv(lightsV[this->lightNumber], GL_POSITION, pos);
}


/**
 *  Prints out some nice formated debug information about the Light
*/
void Light::debug() const
{
  PRINT(0)(":: %d ::  -- reference %p\n", this->lightNumber, this);
  PRINT(0)(" GL-state: ");
  GLboolean param;
  glGetBooleanv(lightsV[this->lightNumber], &param);
  if (param)
    PRINT(0)("ON\n");
  else
    PRINT(0)("OFF\n");

  PRINT(0)(" DiffuseColor:  %f/%f/%f\n", this->diffuseColor[0], this->diffuseColor[1], this->diffuseColor[2]);
  PRINT(0)(" SpecularColor: %f/%f/%f\n", this->specularColor[0], this->specularColor[1], this->specularColor[2]);
  PRINT(0)(" Attenuation: constant=%f linear=%f quadratic=%f\n", this->constantAttenuation, this->linearAttenuation, this->quadraticAttenuation);
}


/******************
** LIGHT-MANAGER **
******************/
/**
 *  standard constructor for a Light
*/
LightManager::LightManager ()
{
  this->setClassID(CL_LIGHT_MANAGER, "LightManager");

  glEnable (GL_LIGHTING);
  this->setAmbientColor(.3, .3, .3);
  this->lights = new Light*[NUMBEROFLIGHTS];
  for (int i = 0; i < NUMBEROFLIGHTS; i++)
    lights[i] = NULL;
  this->currentLight = NULL;
}

/**
 *  standard deconstructor

   first disables Lighting

   then deletes the rest of the allocated memory
   and in the end sets the singleton Reference to zero.
*/
LightManager::~LightManager ()
{
  glDisable(GL_LIGHTING);
  this->setAmbientColor(.0,.0,.0);

  for (int i = 0; i < NUMBEROFLIGHTS; i++)
    if (this->lights[i] != NULL)
      delete lights[i];
  delete[] lights;
  LightManager::singletonRef = NULL;
}

/**
 *  singleton-Reference to the Light-class
*/
LightManager* LightManager::singletonRef = NULL;

/**
* @param root the XML-element to load the LightManager's settings from
 */
void LightManager::loadParams(const TiXmlElement* root)
{
  LoadParamXML(root, "Lights", this, LightManager, loadLights)
      .describe("an XML-Element to load lights from.");

  LoadParam(root, "ambient-color", this, LightManager, setAmbientColor)
      .describe("sets the ambient Color of the Environmental Light");
}

/**
* @param root The XML-element to load Lights from
 */
void LightManager::loadLights(const TiXmlElement* root)
{
  const TiXmlElement* element = root->FirstChildElement();

  while (element != NULL)
  {
    Factory::getFirst()->fabricate(element);

    element = element->NextSiblingElement();
  }
}

// set Attributes
/**
 *  sets the ambient Color of the Scene
 * @param r red
 * @param g green
 * @param b blue
*/
void LightManager::setAmbientColor(GLfloat r, GLfloat g, GLfloat b)
{
  this->ambientColor[0] = r;
  this->ambientColor[1] = g;
  this->ambientColor[2] = b;
  this->ambientColor[3] = 1.0;

  glLightfv (GL_LIGHT0, GL_AMBIENT, this->ambientColor);
}

/**
* @param light the Light to register to the LightManager

  This is done explicitely by the constructor of a Light
*/
int LightManager::registerLight(Light* light)
{
  for (int i = 0; i < NUMBEROFLIGHTS; i++)
    if (!this->lights[i])
  {
    this->lights[i]=light;
    return i;
  }
  PRINTF(1)("no more light slots availiable. All %d already taken\n", NUMBEROFLIGHTS);
  return -1;
}

/**
* @param light The light to unregister from the LightManager

  This is done every time a Light is destroyed explicitely by the Light-destructor
 */
void LightManager::unregisterLight(Light* light)
{
  for (int i = 0; i < NUMBEROFLIGHTS; i++)
  {
    if (this->lights[i] == light)
    {
      this->lights[i] = NULL;
      return;
    }
  }
  PRINTF(2)("Light %p could not be unloaded (this should not heappen\n)");
  return;
}

/**
 *  draws all the Lights in their appropriate position
 */
void LightManager::draw() const
{
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  PRINTF(4)("Drawing the Lights\n");
  for (int i = 0; i < NUMBEROFLIGHTS; i++)
    if (this->lights[i])
      lights[i]->draw();
}

/**
 *  outputs debug information about the Class and its lights
*/
void LightManager::debug() const
{
  PRINT(0)("=================================\n");
  PRINT(0)("= DEBUG INFORMATION CLASS LIGHT =\n");
  PRINT(0)("=================================\n");
  PRINT(0)("Reference: %p\n", LightManager::singletonRef);
  if (this->currentLight)
    PRINT(0)("current Light Nr: %d\n", this->currentLight->getLightNumber());
  PRINT(0)("Ambient Color: %f:%f:%f\n", this->ambientColor[0], this->ambientColor[0], this->ambientColor[0]);
  PRINT(0)("=== Lights ===\n");
  for (int i = 0; i < NUMBEROFLIGHTS; i++)
    if (this->lights[i])
      {
        this->lights[i]->debug();
      }
  PRINT(0)("-----------------------------LM-\n");
}