#include "cbt/opengl/shader.hpp"

#include <iostream>
#include <string>

#include "fmt/std.h"

namespace cbt::opengl {

shader::shader() {}

shader::~shader() {
    if (m_id) {
        glDeleteProgram(m_id);
    }
}

shader::shader(shader&& other) noexcept
    : m_id(other.m_id) {
    other.m_id = 0;
}

shader& shader::operator=(shader&& other) noexcept {
    if (this != &other) {
        if (m_id) {
            glDeleteProgram(m_id);
        }
        m_id = other.m_id;
        other.m_id = 0;
    }
    return *this;
}

auto shader::compile_vertex(char const* source) -> bool {
    auto vert = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vert, 1, &source, nullptr);
    glCompileShader(vert);

    GLint success;
    glGetShaderiv(vert, GL_COMPILE_STATUS, &success);
    if (!success) {
        GLchar info[512];
        glGetShaderInfoLog(vert, 512, nullptr, info);
        fmt::print("Vertex shader compile error:\n{}\n", info);
        glDeleteShader(vert);
        return false;
    }

    if (m_id) {
        glDeleteProgram(m_id);
    }
    m_id = glCreateProgram();
    glAttachShader(m_id, vert);
    glDeleteShader(vert);
    return true;
}

auto shader::compile_fragment(char const* source) -> bool {
    auto frag = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(frag, 1, &source, nullptr);
    glCompileShader(frag);

    GLint success;
    glGetShaderiv(frag, GL_COMPILE_STATUS, &success);
    if (!success) {
        GLchar info[512];
        glGetShaderInfoLog(frag, 512, nullptr, info);
        fmt::print("Fragment shader compile error:\n{}\n", info);
        glDeleteShader(frag);
        return false;
    }

    glAttachShader(m_id, frag);
    glDeleteShader(frag);
    return true;
}

auto shader::link() -> bool {
    glLinkProgram(m_id);

    GLint success;
    glGetProgramiv(m_id, GL_LINK_STATUS, &success);
    if (!success) {
        GLchar info[512];
        glGetProgramInfoLog(m_id, 512, nullptr, info);
        fmt::print("Shader link error:\n{}\n", info);
        glDeleteProgram(m_id);
        m_id = 0;
        return false;
    }
    return true;
}

auto shader::use() const -> void {
    glUseProgram(m_id);
}

auto shader::unuse() const -> void {
    glUseProgram(0);
}

auto shader::id() const -> GLuint {
    return m_id;
}

auto shader::valid() const -> bool {
    return m_id != 0;
}

}