/*
   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_

#include "shader.h"


#include "array.h"
#include "stdlibincl.h"
#include <stdio.h>
#include "debug.h"


#ifndef PARSELINELENGHT
#define PARSELINELENGHT     512       //!< how many chars to read at once
#endif

using namespace std;


/**
 * standard constructor
*/
Shader::Shader (const char* vertexShaderFile, const char* fragmentShaderFile)
{
   this->setClassID(CL_SHADER, "Shader");

   this->fragmentShaderFile = NULL;
   this->vertexShaderFile = NULL;
   this->fragmentShaderSource = NULL;
   this->vertexShaderSource = NULL;
   this->fragmentShaderLengths = NULL;
   this->vertexShaderLenghts = NULL;
   this->shaderProgram = 0;
   this->vertexShader = 0;
   this->fragmentShader = 0;

   if (GLEW_ARB_shader_objects && GLEW_ARB_shading_language_100)
     this->shaderProgram = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);

   if (vertexShaderFile != NULL)
     this->loadShaderProgramm(SHADER_VERTEX, vertexShaderFile);
   if (fragmentShaderFile != NULL)
     this->loadShaderProgramm(SHADER_FRAGMENT, fragmentShaderFile);
   glLinkProgramARB(this->shaderProgram);
   this->printError(this->shaderProgram);

}


/**
 * standard deconstructor
*/
Shader::~Shader ()
{
  // delete what has to be deleted here
  this->deleteProgram(SHADER_VERTEX);
  this->deleteProgram(SHADER_FRAGMENT);

  glDeleteObjectARB(this->shaderProgram);
}


bool Shader::loadShaderProgramm(SHADER_TYPE type, const char* fileName)
{
  if (type != SHADER_VERTEX && type != SHADER_FRAGMENT)
    return false;
  this->deleteProgram(type);

  FILE*    stream;           //< The stream we use to read the file.

  if( (stream = fopen (fileName, "r")) == NULL)
  {
    PRINTF(1)("Shader could not open %s\n", fileName);
    return false;
  }
  Array<char*>* program = new Array<char*>;
  Array<int>* lengths = new Array<int>;
  if (type == SHADER_VERTEX)
  {
    this->vertexShaderFile = new char[strlen(fileName)+1];
    strcpy(this->vertexShaderFile, fileName);
    this->vertexShaderSource = program;
    this->vertexShaderLenghts = lengths;
  }
  else
  {
    this->fragmentShaderFile = new char[strlen(fileName)+1];
    strcpy(this->fragmentShaderFile, fileName);
    this->fragmentShaderSource = program;
    this->fragmentShaderLengths = lengths;
  }

  char lineBuffer[PARSELINELENGHT];
  char* addString;
  while( !feof( stream))
  {
      // get next line
    fgets (lineBuffer, PARSELINELENGHT, stream);
//     if (strchr(lineBuffer, '\n'))
//     {
//       addString = new char[strlen(lineBuffer)];
//       strncpy(addString, lineBuffer, strlen (lineBuffer)-1);
//       addString[strlen(lineBuffer)-1] ='\0';
//     }
//     else
    {
      addString = new char[strlen(lineBuffer)+1];
      strcpy(addString, lineBuffer);
    }
    program->addEntry(addString);
    lengths->addEntry(strlen(addString));
  }
  fclose(stream);

  program->finalizeArray();
  lengths->finalizeArray();

  if (type == SHADER_VERTEX && GLEW_ARB_vertex_shader)
  {
    this->vertexShader = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
    glShaderSourceARB(this->vertexShader, program->getCount(), (const GLcharARB**)program->getArray(), lengths->getArray());
    glCompileShaderARB(this->vertexShader);
    glAttachObjectARB(this->shaderProgram, this->vertexShader);
    this->printError(this->vertexShader);
  }

  if (type == SHADER_FRAGMENT && GLEW_ARB_fragment_shader)
  {
    this->fragmentShader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
    glShaderSourceARB(this->fragmentShader, program->getCount(), (const GLcharARB**)program->getArray(), lengths->getArray());
    glCompileShaderARB(this->fragmentShader);
    glAttachObjectARB(this->shaderProgram, this->fragmentShader);
    this->printError(this->fragmentShader);
  }
}

bool Shader::activateShader()
{
  glUseProgramObjectARB(this->shaderProgram);
}


void Shader::deleteProgram(SHADER_TYPE type)
{
  Array<char*>* deleteArray = NULL;
  if (type == SHADER_VERTEX)
  {
    deleteArray = this->vertexShaderSource;
    this->vertexShaderSource = NULL;
    delete this->vertexShaderLenghts;
    this->vertexShaderLenghts = NULL;
    delete[] this->vertexShaderFile;
    this->vertexShaderFile = NULL;
    glDeleteObjectARB(this->vertexShader);
    this->vertexShader = 0;
  }
  else if (type == SHADER_FRAGMENT)
  {
    deleteArray = this->fragmentShaderSource;
    delete this->fragmentShaderLengths;
    this->fragmentShaderLengths = NULL;
    this->fragmentShaderSource = NULL;
    delete[] this->fragmentShaderFile;
    this->fragmentShaderFile = NULL;
    glDeleteObjectARB(this->fragmentShader);
    this->fragmentShader = 0;
  }
  else
    return;

  if (deleteArray == NULL)
    return;
  else
  {
    deleteArray->finalizeArray();
    for (unsigned int i = 0; i < deleteArray->getCount(); i++)
    {
      delete[] deleteArray->getEntry(i);
    }
    delete deleteArray;
  }
}


void Shader::printError(GLenum program)
{
  GLint length = 5000;
//  glGetObjectParameterARBfiv(program, GL_OBJECT_INFO_LOG_LENGTH_ARB, &length);
  char* text = new char[length+1];
  glGetInfoLogARB(program, length, &length, text);
  printf("%s\n", text);
  delete[] text;
}



void Shader::debug() const
{
  PRINT(3)("Shader info: (SHADER: %d)\n", this->shaderProgram);
  if (this->vertexShader != 0)
  {
    PRINT(3)("VertexShaderProgramm: number=%d, file='%s'\n", this->vertexShader, this->vertexShaderFile);
    if (this->vertexShaderSource != NULL)
      for (unsigned int i = 0; i < this->vertexShaderSource->getCount(); i++)
        PRINT(3)("%d: %s\n", i, this->vertexShaderSource->getEntry(i));
  }
  if (this->fragmentShader != 0)
  {
    PRINT(3)("FragmentShaderProgramm: number=%d, file='%s'\n", this->fragmentShader, this->fragmentShaderFile);
    if (this->fragmentShaderSource != NULL)
      for (unsigned int i = 0; i < this->fragmentShaderSource->getCount(); i++)
        PRINT(3)("%d: %s\n", i, this->fragmentShaderSource->getEntry(i));
  }


}