// Dear ImGui: standalone example application for GLFW + OpenGL2, using legacy fixed pipeline
// (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)

// Learn about Dear ImGui:
// - FAQ                  https://dearimgui.com/faq
// - Getting Started      https://dearimgui.com/getting-started
// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
// - Introduction, links and more at the top of imgui.cpp

// **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
// **Prefer using the code in the example_glfw_opengl2/ folder**
// See imgui_impl_glfw.cpp for details.

#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl2.h"
#include <stdio.h>
#ifdef __APPLE__
#define GL_SILENCE_DEPRECATION
#endif
#include <GLFW/glfw3.h>

#include "timer.h"
#include "ui.hpp"
#include "administration.hpp"
#include "administration_writer.hpp"
#include "administration_reader.hpp"

// [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
// To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
// Your own project should not be affected, as you are likely to link with a newer binary of GLFW that is adequate for your version of Visual Studio.
#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
#pragma comment(lib, "legacy_stdio_definitions")
#endif

static void glfw_error_callback(int error, const char* description)
{
    fprintf(stderr, "GLFW Error %d: %s\n", error, description);
}

// Main code
int main(int argc, char** argv)
{
    glfwSetErrorCallback(glfw_error_callback);
    if (!glfwInit())
        return 1;

    // Create window with graphics context
    float main_scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfwGetPrimaryMonitor()); // Valid on GLFW 3.3+ only
    GLFWwindow* window = glfwCreateWindow((int)(1280 * main_scale), (int)(800 * main_scale), "OpenBooks", nullptr, nullptr);
    if (window == nullptr)
        return 1;
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1); // Enable vsync

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    //ImGui::StyleColorsLight();

    // Setup scaling
    ImGuiStyle& style = ImGui::GetStyle();
    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)

    // Setup Platform/Renderer backends
    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL2_Init();

    style.FontSizeBase = 18.0f;
    io.Fonts->AddFontFromFileTTF("build/Segoe UI.ttf");
    ui::fontBold = io.Fonts->AddFontFromFileTTF("build/Segoe UI Bold.ttf");
    ui::fontBig = io.Fonts->AddFontFromFileTTF("build/Segoe UI Bold.ttf", 30);
    
    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

    timer_lib_initialize();
    administration_writer::create();

    if (argc < 2) {
        administration::create_default("");
    }
    else {
        administration_reader::open_existing(argv[1]);
    }

    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        if (glfwGetWindowAttrib(window, GLFW_ICONIFIED) != 0)
        {
            ImGui_ImplGlfw_Sleep(10);
            continue;
        }

        // Start the Dear ImGui frame
        ImGui_ImplOpenGL2_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ui::draw_main();

        // Rendering
        ImGui::Render();
        int display_w, display_h;
        glfwGetFramebufferSize(window, &display_w, &display_h);
        glViewport(0, 0, display_w, display_h);
        glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
        glClear(GL_COLOR_BUFFER_BIT);

        // If you are using this code with non-legacy OpenGL header/contexts (which you should not, prefer using imgui_impl_opengl3.cpp!!),
        // you may need to backup/reset/restore other state, e.g. for current shader using the commented lines below.
        //GLint last_program;
        //glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
        //glUseProgram(0);
        ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
        //glUseProgram(last_program);

        glfwMakeContextCurrent(window);
        glfwSwapBuffers(window);
    }

    administration_writer::destroy();
    timer_lib_shutdown();
    administration::destroy();

    // Cleanup
    ImGui_ImplOpenGL2_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    glfwDestroyWindow(window);
    glfwTerminate();

    return 0;
}