////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2011, Computer Graphics Group RWTH Aachen University         //
// All rights reserved.                                                       //
////////////////////////////////////////////////////////////////////////////////

#include <ACGL/Resource/Shader.hh>
#include <ACGL/GLUtils/Tools.hh>
#include <ACGL/Utils/Log.hh>

#include <iostream>
#include <fstream>

using namespace ACGL::Utils;
using namespace ACGL::GLUtils;
using namespace ACGL::GLUtils::Tools;
using namespace ACGL::Resource;

bool Shader::setFromFile(const std::string& _filename)
{
    std::string line = "";
    std::string fileContent = "";
    
    std::ifstream fileStream(_filename.c_str(), std::ifstream::in);
    
    if(fileStream.is_open())
    {
        while (fileStream.good())
        {
            std::getline(fileStream,line);
            fileContent += line + "\n";
        }
        fileStream.close();
    }
    else
    {
        error() << "Failed to open file: " << _filename << std::endl;
        return false;
    }
    
    return setSource(fileContent);
}

bool Shader::setSource(const std::string& _source)
{
    return compile(_source.c_str());
}

bool Shader::compile(const char* _pProgramText) const
{
    glShaderSource(mContext, 1, &_pProgramText, NULL);
    openGLRareError();
    glCompileShader(mContext);
    
    if ( openGLCommonErrorOccured() )
    {
        return false;
    }

    // check for shader compile errors:
    GLint shaderError;
    glGetShaderiv(mContext, GL_COMPILE_STATUS, &shaderError);
    if(shaderError != GL_TRUE)
    {
        // yes, errors
        error() << "Shader compile error: " << std::endl;
    }

    GLsizei length = 0;
    glGetShaderiv(mContext, GL_INFO_LOG_LENGTH, &length);
    if(length > 1)
    {
        // a compile log can get produced even if there were no errors, but warnings!
        GLchar* pInfo = new char[length + 1];
        glGetShaderInfoLog(mContext,  length, &length, pInfo);
        error() << "Compile log: " << std::string(pInfo) << std::endl;
        delete[] pInfo;
    }
    return (shaderError == GL_TRUE); // return true if we encountered no errors
}