#include <cstdlib>
#include <thread>
#include <chrono>
#include <atomic>
#include <mutex>

#include <GLFW/glfw3.h>

#include <imgui.h>
#include <imgui_impl_glfw.h>
#include <imgui_impl_opengl3.h>

static std::atomic<bool> terminate_dsp;
static std::mutex waterfall_data_mutex;
static int waterfall_width = 1600;
static int waterfall_height = 700;
static unsigned int waterfall_data[1600*700];

static void dsp_thread() {
    using namespace std::chrono_literals;

    int t = 0;
    while(!terminate_dsp) {
        t++;
        {
            std::lock_guard<std::mutex> guard(waterfall_data_mutex);
            for(int y=0;y<waterfall_height;y++)
                for(int x=0;x<waterfall_width;x++)
                    waterfall_data[y*waterfall_width+x] = (x+y+t) | 0xff000000;
        }
        std::this_thread::sleep_for(20ms);
    };
}

int main(int, char**)
{
    if (!glfwInit())
        return 1;
    std::atexit(glfwTerminate);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
    static GLFWwindow* window = glfwCreateWindow(1900, 720, "microsa", nullptr, nullptr);
    if (window == nullptr) {
        return 1;
    }
    static auto DestroyWindow = []() {
        glfwDestroyWindow(window);
    };
    std::atexit(DestroyWindow);
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1);

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    static auto ImGuiDestroyContext = []() {
        ImGui::DestroyContext();
    };
    std::atexit(ImGuiDestroyContext);
    ImGuiIO& io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
    ImGui::StyleColorsDark();
    ImGui_ImplGlfw_InitForOpenGL(window, true);
    std::atexit(ImGui_ImplGlfw_Shutdown);
    ImGui_ImplOpenGL3_Init("#version 130");
    std::atexit(ImGui_ImplOpenGL3_Shutdown);

    GLuint waterfall;
    glGenTextures(1, &waterfall);
    glBindTexture(GL_TEXTURE_2D, waterfall);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    terminate_dsp = false;
    static std::thread dsp_thread_h = std::thread(dsp_thread);
    static auto TerminateDSP = []() {
        terminate_dsp = true;
        dsp_thread_h.join();
    };
    std::atexit(TerminateDSP);

    bool exit = false;
    while(!exit && !glfwWindowShouldClose(window)) {
        glfwPollEvents();
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glBindTexture(GL_TEXTURE_2D, waterfall);
        #if defined(GL_UNPACK_ROW_LENGTH) && !defined(__EMSCRIPTEN__)
        glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
        #endif
        {
            std::lock_guard<std::mutex> guard(waterfall_data_mutex);
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, waterfall_width, waterfall_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, waterfall_data);
        }

        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ImGui::SetNextWindowPos(ImVec2(0.0f, 0.0f));
        ImGui::SetNextWindowSize(io.DisplaySize);
        ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
        ImGui::Begin("microsa", nullptr, ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoResize);

        ImGui::BeginTable("microsa", 2, ImGuiTableFlags_SizingStretchSame | ImGuiTableFlags_Resizable);
        ImGui::TableSetupColumn("", 0, 280.0);
        ImGui::TableSetupColumn("", 0, 1600.0);
        ImGui::TableNextColumn();
        if(ImGui::Button("Exit"))
            exit = true;
        ImGui::TableNextColumn();
        ImGui::Image((void*)(intptr_t)waterfall, ImVec2(waterfall_width, waterfall_height));
        ImGui::EndTable();

        ImGui::End();
        ImGui::PopStyleVar(1);

        // Rendering
        ImGui::Render();
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
        int display_w, display_h;
        glfwGetFramebufferSize(window, &display_w, &display_h);
        glViewport(0, 0, display_w, display_h);
        glfwSwapBuffers(window);
    }

    return 0;
}