/* moontalk-imgui.cpp - Dear ImGui frontend
 * written by an Anon. https://boards.4chan.org/g/thread/98813374#p98826333
 */

#include <imgui.h>
#include <imgui_stdlib.h>
#include <imgui_impl_sdl2.h>
#include <imgui_impl_sdlrenderer2.h>
#include <SDL.h>

#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <err.h>
#include <stdio.h>
#include <unistd.h>

#include <vector>
#include <string>
#include <thread>
#include <mutex>
#include <queue>

#define SERV "7ks473deh6ggtwqsvbqdurepv5i6iblpbkx33b6cydon3ajph73sssad.onion"
#define PORT "50000"

static int moontalk_fd = -1;
static std::mutex inqueue_lock;
static std::queue<std::string> inqueue;
static std::vector<std::string> moontalk_lines;

int tcp_connect(const char* addr, const char *port)
{
    struct addrinfo hints;
    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    struct addrinfo* res;
    int status = getaddrinfo(addr, port, &hints, &res);
    if (status != 0)
        errx(1, "getaddrinfo: %s", gai_strerror(status));

    int fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    if (fd < 0)
        err(1, "socket");

    if (connect(fd, res->ai_addr, res->ai_addrlen))
        err(1, "socket");

    freeaddrinfo(res);
    return fd;
}

void moontalk_send(const std::string& line)
{
    char timebuf[256];

    time_t t = time(NULL);;
    struct tm * tm;
    tm = gmtime(&t);
    strftime(timebuf, sizeof(timebuf), "<%Y/%m/%d %H:%M:%S ", tm);


    std::string out;
    out += timebuf;
    out += line;
    if (line.at(line.size()-1) != '\n') out.push_back('\n');

    send(moontalk_fd, out.data(), out.size(), 0);
    printf("send %s", out.c_str());
}

void read_loop()
{
    char buffer[4096];
    size_t pos = 0;

    for (;;) {
        ssize_t r = read(moontalk_fd, buffer + pos, sizeof(buffer) - pos);
        if (r < 0) {
            if (r == EINTR)
                continue;
            err(1, "read");
        }
        pos += r;

        // scan lines and push them to inqueue
        size_t start = 0;
        size_t end = 0;
        while (end < pos) {
            if (buffer[end] == '\n') {
                std::string line = {buffer + start, buffer + end+1};

                inqueue_lock.lock();
                inqueue.push(std::move(line));
                inqueue_lock.unlock();

                start = end+1;
                end = end+1;
            } else {
                end++;
            }
        }
        if (start != 0) {
            memmove(buffer, buffer+start, pos-start);
            pos -= start;
        }
    }
}

void ui()
{
    static std::string input;

    if (ImGui::Begin("Chat")) {
        for (auto& line : moontalk_lines) {
            ImGui::TextUnformatted(line.c_str());
        }
        ImGui::End();
    }

    if (ImGui::Begin("Input")) {
        ImGui::InputText("Input", &input);
        if (ImGui::Button("Send")) {
            moontalk_send(input);
            input.clear();
        }

        // TODO or make it separate window and handle the layout on docking layer
        ImGui::End();
    }
}

int main(int argc, char *argv[])
{
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
        err(1, "SDL_Init: %s", SDL_GetError());

    // From 2.0.18: Enable native IME.
#ifdef SDL_HINT_IME_SHOW_UI
    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
#endif

    SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
    SDL_Window* window = SDL_CreateWindow("moontalk", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
    if (!window)
        err(1, "SDL_CreateWindow: %s", SDL_GetError());

    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED);
    if (renderer == nullptr)
        err(1, "SDL_CreateRenderer: %s", SDL_GetError());

    // 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
    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
    // io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
    //io.ConfigViewportsNoAutoMerge = true;
    //io.ConfigViewportsNoTaskBarIcon = true;

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

    // Setup Platform/Renderer backends
    ImGui_ImplSDL2_InitForSDLRenderer(window, renderer);
    ImGui_ImplSDLRenderer2_Init(renderer);

    // Load Fonts
    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
    // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
    // - Read 'docs/FONTS.md' for more instructions and details.
    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
    //io.Fonts->AddFontDefault();
    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
    //IM_ASSERT(font != nullptr);

    // setup
    fprintf(stderr, "Connecting...\n");
    moontalk_fd = tcp_connect(SERV, PORT);
    fprintf(stderr, "Connected\n");

    std::thread t(read_loop);

    bool done = false;
    while (!done) {
        // Poll and handle events (inputs, window resize, etc.)
        // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
        // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
        // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
        // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            ImGui_ImplSDL2_ProcessEvent(&event);
            if (event.type == SDL_QUIT)
                done = true;
            if (event.type == SDL_WINDOWEVENT && event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window))
                done = true;
        }

        inqueue_lock.lock();
        if (!inqueue.empty()) {
            std::string line = std::move(inqueue.front());
            inqueue.pop();
            moontalk_lines.push_back(std::move(line));
        }
        inqueue_lock.unlock();

        // Start the Dear ImGui frame
        ImGui_ImplSDLRenderer2_NewFrame();
        ImGui_ImplSDL2_NewFrame();
        ImGui::NewFrame();

        ImGui::DockSpaceOverViewport(ImGui::GetMainViewport());

        ui();

        // Rendering
        ImGui::Render();
        SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 1);
        SDL_RenderClear(renderer);
        ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData());
        SDL_RenderPresent(renderer);
    }

    // Cleanup
    ImGui_ImplSDLRenderer2_Shutdown();
    ImGui_ImplSDL2_Shutdown();
    ImGui::DestroyContext();

    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();

    close(moontalk_fd);

    return 0;
}