#include <luna/Sort.h>
#include <luna/StringBuilder.h>
#include <os/Directory.h>
#include <os/File.h>
#include <os/FileSystem.h>
#include <os/IPC.h>
#include <os/Process.h>
#include <os/ipc/Launcher.h>
#include <signal.h>
#include <sys/wait.h>
#include <ui/App.h>
#include <ui/Button.h>
#include <ui/Container.h>
#include <ui/Image.h>
#include <ui/Layout.h>

static constexpr ui::Color TASKBAR_COLOR = ui::Color::from_rgb(83, 83, 83);

static OwnedPtr<os::IPC::Client> launcher_client;

void sigchld_handler(int)
{
    wait(nullptr);
}

void sighup_handler(int)
{
    // Reload the taskbar by exec-ing the executable, resetting everything.
    StringView args[] = { "/usr/bin/taskbar" };
    os::Process::exec(args[0], { args, 1 });
}

Result<void> create_widget_group_for_app(ui::HorizontalLayout& layout, StringView path, StringView icon)
{
    auto* button = TRY(make<ui::Button>(ui::Rect { 0, 0, 50, 50 }));
    layout.add_widget(*button);

    auto* container = TRY(
        make<ui::Container>(ui::Rect { 0, 0, 50, 50 }, ui::VerticalAlignment::Center, ui::HorizontalAlignment::Center));
    button->set_widget(*container);
    button->set_action([=] {
        os::Launcher::LaunchDetachedRequest request;
        SET_IPC_STRING(request.command, path.chars());
        launcher_client->send_async(request);
    });

    auto image = TRY(ui::ImageWidget::load(icon));
    container->set_widget(*image);

    image.leak();

    return {};
}

struct ApplicationFile
{
    String name;
    String command;
    String icon;
};

Vector<ApplicationFile> s_app_files;

// Pretty much copied from init.cpp.
static Result<void> load_application_file(const os::Path& path)
{
    os::println("[taskbar] reading app file: %s", path.name().chars());

    auto file = TRY(os::File::open(path, os::File::ReadOnly));

    ApplicationFile app_file;

    while (true)
    {
        auto line = TRY(file->read_line());
        if (line.is_empty()) break;

        line.trim("\n");
        if (line.is_empty()) continue;

        auto parts = TRY(line.split_once('='));
        if (parts.size() < 2 || parts[0].is_empty() || parts[1].is_empty())
        {
            os::println("[taskbar] file contains invalid line, aborting: '%s'", line.chars());
            return {};
        }

        if (parts[0].view() == "Name")
        {
            app_file.name = move(parts[1]);
            continue;
        }

        if (parts[0].view() == "Description")
        {
            // We let users specify this in the config file, but taskbar doesn't actually use it.
            continue;
        }

        if (parts[0].view() == "Command")
        {
            app_file.command = move(parts[1]);
            continue;
        }

        if (parts[0].view() == "Icon")
        {
            app_file.icon = move(parts[1]);
            continue;
        }

        os::println("[taskbar] skipping unknown entry name %s", parts[0].chars());
    }

    if (app_file.icon.is_empty())
    {
        os::println("[taskbar] app file is missing 'Icon' entry, aborting!");
        return {};
    }

    if (app_file.command.is_empty())
    {
        os::println("[taskbar] app file is missing 'Command' entry, aborting!");
        return {};
    }

    os::println("[taskbar] loaded app %s into memory", app_file.name.chars());

    TRY(s_app_files.try_append(move(app_file)));

    return {};
}

static Result<void> load_app_files_from_path(StringView path)
{
    os::println("[taskbar] loading app files from %s", path.chars());

    auto dir = TRY(os::Directory::open(path));

    auto services = TRY(dir->list_names(os::Directory::Filter::ParentAndBase));
    sort(services.begin(), services.end(), String::compare);

    for (const auto& entry : services) TRY(load_application_file({ dir->fd(), entry.view() }));

    return {};
}

Result<int> luna_main(int, char**)
{
    ui::App app;
    TRY(app.init("/tmp/wsys.sock"));

    TRY(os::EventLoop::the().register_signal_handler(SIGCHLD, sigchld_handler));
    TRY(os::EventLoop::the().register_signal_handler(SIGHUP, sighup_handler));

    launcher_client = TRY(os::IPC::Client::connect("/tmp/launch.sock", false));

    ui::Rect screen = app.screen_rect();

    ui::Rect bar = ui::Rect { ui::Point { 0, screen.height - 50 }, screen.width, 50 };

    auto window = TRY(ui::Window::create(bar, ui::WindowType::System));
    app.set_main_window(window);

    window->set_background(TASKBAR_COLOR);
    window->set_special_attributes(ui::UNFOCUSEABLE);

    ui::HorizontalLayout layout(ui::Margins { 0, 0, 0, 0 }, ui::AdjustHeight::Yes, ui::AdjustWidth::No);
    window->set_main_widget(layout);

    load_app_files_from_path("/usr/share/applications/");

    auto home = TRY(os::FileSystem::home_directory());

    StringBuilder sb;
    TRY(sb.add(home.view()));
    TRY(sb.add("/.applications/"_sv));
    auto local_app_file_dir = TRY(sb.string());

    load_app_files_from_path(local_app_file_dir.view());

    for (const auto& app_file : s_app_files)
    {
        create_widget_group_for_app(layout, app_file.command.view(), app_file.icon.view());
    }

    return app.run();
}