#include <GL/glew.h>
#include <stdexcept>
#include "Program.hpp"

#include "../../Common/Assert.hpp"

namespace MC::GFX::Shading {

Program::Program(Shader vertex, Shader fragment) {
    m_program = glCreateProgram();

    glAttachShader(m_program, fragment.get());
    glAttachShader(m_program, vertex.get());

    glLinkProgram(m_program);

    glDeleteShader(fragment.get());
    glDeleteShader(vertex.get());

    GLint success;
    glGetProgramiv(m_program, GL_LINK_STATUS, &success);
    if(!success) {
        Char message[512] = {};
        glGetProgramInfoLog(m_program, 512, nullptr, message);

        throw std::runtime_error(message);
    }
}

void Program::bind() const {
    ASSERT(m_program != 0, "Program is not initialized");
    glUseProgram(m_program);
}

void Program::unbind() const {
    glUseProgram(0);
}

std::optional<Uniform> Program::uniform(const std::string& name) const {
    ASSERT(m_program != 0, "Program is not initialized");
    auto index = glGetUniformLocation(m_program, name.c_str());

    if (index == -1) return {};
    return {{name, static_cast<U32>(index)}};
}

U32 Program::get() const {
    return m_program;
}

}