#include "GLProgram.h"
#include "ruby.h"
#include "gl3w.h"

typedef struct
{
    GLuint id;
} GLProgram;

static VALUE ruby_class;

static void GLProgram_free(void * ptr)
{
    GLProgram * program = (GLProgram *)ptr;

    if (program->id > 0u)
    {
        glDeleteProgram(program->id);
    }

    delete program;
}

static VALUE GLProgram_new(VALUE klass)
{
    GLProgram * glprogram = new GLProgram();

    glprogram->id = glCreateProgram();
    if (glprogram->id == 0u)
    {
        rb_raise(rb_eRuntimeError, "Error allocating GL program object");
    }

    return Data_Wrap_Struct(klass, NULL, GLProgram_free, glprogram);
}

void GLProgram_Init()
{
    ruby_class = rb_define_class("GLProgram", rb_cObject);
    rb_define_singleton_method(ruby_class, "new", (VALUE(*)(...))GLProgram_new, 0);
    rb_define_attr(ruby_class, "id", 0, 1);
}

#if 0
GLProgram & GLProgram::attach_shader(GLShaderRef shader)
{
    if (m_id > 0u)
    {
        glAttachShader(m_id, shader->get_id());
    }
    return *this;
}

GLProgram & GLProgram::bind_attribute(const char * attribute, GLuint index)
{
    if (m_id > 0u)
    {
        glBindAttribLocation(m_id, index, attribute);
    }
    return *this;
}

bool GLProgram::link()
{
    if (m_id == 0u)
        return false;

    glLinkProgram(m_id);

    GLint link_status;
    glGetProgramiv(m_id, GL_LINK_STATUS, &link_status);
    if (link_status != GL_TRUE)
    {
        GLint log_length;
        glGetProgramiv(m_id, GL_INFO_LOG_LENGTH, &log_length);
        if (log_length > 0)
        {
            char *log = new char[log_length];
            glGetProgramInfoLog(m_id, log_length, &log_length, log);
            cerr << "Program log:" << endl << log << endl;
            delete[] log;
        }
        return false;
    }

    return true;
}

GLint GLProgram::get_uniform(const std::string & uniform_name)
{
    if (m_id > 0u)
    {
        auto it = m_uniforms.find(uniform_name);
        if (it != m_uniforms.end())
        {
            return it->second;
        }
        GLint loc = glGetUniformLocation(m_id, uniform_name.c_str());
        m_uniforms[uniform_name] = loc;
        return loc;
    }
    return -1;
}
#endif