#include "client/render/program.hh"

namespace client {
namespace render {

static void check_shader(const GLuint shader) {
    int status = 0;
    char info[512];
    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);

    if (!status) {
        glGetShaderInfoLog(shader, 512, nullptr, info);
        throw std::runtime_error(std::string("failed to compile shader: ") +
                                 info);
    }
}

static void check_program(const GLuint program) {
    int status = 0;
    char info[512];
    glGetProgramiv(program, GL_LINK_STATUS, &status);

    if (!status) {
        glGetProgramInfoLog(program, 512, nullptr, info);
        throw std::runtime_error(std::string("failed to link program: ") +
                                 info);
    }
}

program::program(const std::string_view vpath, const std::string_view fpath) {
    const auto make_shader = [](const auto& path, const auto type) -> GLuint {
        const std::string source = shared::read_file(path.data());
        const char* const src_ptr = source.c_str();
        GLuint shader = glCreateShader(type);
        glShaderSource(shader, 1, &src_ptr, nullptr);
        glCompileShader(shader);
        check_shader(shader);
        return shader;
    };

    GLuint vertex = make_shader(vpath, GL_VERTEX_SHADER);
    GLuint fragment = make_shader(fpath, GL_FRAGMENT_SHADER);

    this->index = glCreateProgram();
    glAttachShader(this->index, vertex);
    glAttachShader(this->index, fragment);
    glLinkProgram(this->index);
    check_program(this->index);

    glDeleteShader(vertex);
    glDeleteShader(fragment);
}

} // namespace render
} // namespace client