#include <cassert>
#include <csignal>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <optional>
#include <poll.h>
#include <print>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/signalfd.h>
#include <thread>
#include <unordered_set>
#include <vector>

#include <EGL/egl.h>
#include <GLES3/gl3.h>
#include <glib.h>
#include <libportal/portal.h>
#include <raylib.h>
#include <rlgl.h>
#include <wayland-egl.h>
#include <xkbcommon/xkbcommon.h>

#define namespace namespace_
#include "wlr-layer-shell-unstable-v1-client-protocol.h"
extern "C" {
#include <libportal/settings.h>
}
#undef namespace

#include "blur-client-protocol.h"
#include "ext-background-effect-v1-client-protocol.h"

#include <wayland-client.h>

#include "Theme.hpp"
#include "common.hpp"

struct TypingBuffer : std::pmr::vector<u32> {
  void push_utf8(const char *s) {
    for (const unsigned char *p = (const unsigned char *)s; *p;) {
      u32 cp = 0;
      int len = 0;
      if (*p < 0x80) {
        cp = *p++;
        len = 1;
      } else if ((*p & 0xE0) == 0xC0) {
        cp = *p++ & 0x1F;
        len = 2;
      } else if ((*p & 0xF0) == 0xE0) {
        cp = *p++ & 0x0F;
        len = 3;
      } else {
        cp = *p++ & 0x07;
        len = 4;
      }
      for (int i = 1; i < len; i++)
        cp = (cp << 6) | ((*p++) & 0x3F);
      push_back(cp);
    }
  }
};

struct App {
  App() {
    init_wayland();
    init_egl();
    init_signal();
    init_theme_portal();
  }
  ~App();

  auto run() -> void {
    SetWindowSize(m_win_w, m_win_h);
    while (m_running) {
      pump_events();
      render_frame();
      std::this_thread::sleep_for(std::chrono::milliseconds(16));
    }
  }
  auto set_visible(bool visible) -> void;
  auto visible() const -> bool { return m_visible; }

  auto stop() -> void { m_running = false; }

private:
  auto init_wayland() -> void;
  auto init_egl() -> void;
  auto init_signal() -> void;
  auto init_theme_portal() -> void;
  auto pump_events() -> void;
  auto render_frame() -> void;
  auto create_layer_surface() -> void;
  auto destroy_layer_surface() -> void;
  auto ensure_egl_surface() -> void;
  auto update_blur_region() -> void;
  auto theme() const -> ColorScheme const & { return m_themes[m_active_theme]; }

  static void on_settings_changed(XdpSettings * /*self*/, const char *ns,
                                  const char *key, GVariant * /*value*/,
                                  gpointer data);

  struct {
    wl_display *display{};
    wl_registry *registry{};
    wl_compositor *compositor{};
    wl_seat *seat{};
    wl_keyboard *kbd{};
    wl_surface *wl_surface{};
    zwlr_layer_shell_v1 *layer_shell{};
    zwlr_layer_surface_v1 *layer_surface{};
    ext_background_effect_manager_v1 *mgr{};
    ext_background_effect_surface_v1 *eff{};
    org_kde_kwin_blur_manager *kde_blur_mgr{};
    org_kde_kwin_blur *kde_blur{};
  } m_wayland;

  struct {
    EGLDisplay edpy{EGL_NO_DISPLAY};
    EGLConfig ecfg{};
    EGLContext ectx{EGL_NO_CONTEXT};
    EGLSurface esurf{EGL_NO_SURFACE};
    wl_egl_window *wegl{};
  } m_gl;

  struct {
    XdpPortal *portal{};
    XdpSettings *settings{};
  } m_xdp;

  struct {
    TypingBuffer typing{};

    xkb_context *xkb_ctx{};
    xkb_keymap *xkb_keymap{};
    xkb_state *xkb_state{};

    std::unordered_set<u32> held;
    std::unordered_set<u32> pressed_syms;
    std::unordered_set<u32> released_syms;

    auto is_down_evdev(u32 evdev) const -> bool {
      return held.find(evdev) != held.end();
    }

    auto is_down_sym(xkb_keysym_t sym) const -> bool {
      if (!xkb_state)
        return false;
      for (auto k : held) {
        if (xkb_state_key_get_one_sym(xkb_state, (xkb_keycode_t)(k + 8)) == sym)
          return true;
      }
      return false;
    }

    auto is_sym_pressed(xkb_keysym_t sym) const -> bool {
      return pressed_syms.find(sym) != pressed_syms.end();
    }

    auto is_sym_released(xkb_keysym_t sym) const -> bool {
      return released_syms.find(sym) != released_syms.end();
    }

    auto mod_active(const char *name) const -> bool {
      return xkb_state && xkb_state_mod_name_is_active(
                              xkb_state, name, XKB_STATE_MODS_EFFECTIVE) > 0;
    }

    auto ctrl() const -> bool { return mod_active("Control"); }
    auto shift() const -> bool { return mod_active("Shift"); }

    void clear_transients() {
      pressed_syms.clear();
      released_syms.clear();
    }
  } m_kbd;

  enum_array<Theme, ColorScheme> m_themes{make_default_themes()};
  Theme m_active_theme{Theme::Light};

  int m_win_w{800};
  int m_win_h{600};
  bool m_running{true};
  bool m_visible{true};

  int m_sfd{-1}; // Signal fd for toggling visibility
};

App::~App() {
  if (m_sfd != -1)
    close(m_sfd);

  destroy_layer_surface();

  if (m_gl.edpy != EGL_NO_DISPLAY) {
    if (m_gl.ectx != EGL_NO_CONTEXT)
      eglDestroyContext(m_gl.edpy, m_gl.ectx);
    eglTerminate(m_gl.edpy);
  }

  if (m_kbd.xkb_state)
    xkb_state_unref(m_kbd.xkb_state);
  if (m_kbd.xkb_keymap)
    xkb_keymap_unref(m_kbd.xkb_keymap);
  if (m_kbd.xkb_ctx)
    xkb_context_unref(m_kbd.xkb_ctx);
  if (m_wayland.kbd)
    wl_keyboard_destroy(m_wayland.kbd);
  if (m_wayland.seat)
    wl_seat_destroy(m_wayland.seat);
  if (m_wayland.compositor)
    wl_compositor_destroy(m_wayland.compositor);
  if (m_wayland.registry)
    wl_registry_destroy(m_wayland.registry);
  if (m_wayland.display)
    wl_display_disconnect(m_wayland.display);

  if (m_xdp.settings)
    g_object_unref(m_xdp.settings);
  if (m_xdp.portal)
    g_object_unref(m_xdp.portal);
}

auto App::init_wayland() -> void {
  m_wayland.display = wl_display_connect(nullptr);
  if (!m_wayland.display) {
    std::fprintf(stderr, "failed to connect to Wayland display\n");
    std::exit(EXIT_FAILURE);
  }

  static wl_keyboard_listener keyboard_listener{};
  {
    auto kb_keymap = [](void *data, wl_keyboard *, u32 format, i32 fd,
                        u32 size) -> void {
      auto *app = (App *)data;
      if (format != WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1) {
        close(fd);
        return;
      }
      void *map = mmap(nullptr, size, PROT_READ, MAP_PRIVATE, fd, 0);
      if (map == MAP_FAILED) {
        close(fd);
        return;
      }
      if (app->m_kbd.xkb_keymap)
        xkb_keymap_unref(app->m_kbd.xkb_keymap);
      if (app->m_kbd.xkb_state) {
        xkb_state_unref(app->m_kbd.xkb_state);
        app->m_kbd.xkb_state = nullptr;
      }
      app->m_kbd.xkb_keymap = xkb_keymap_new_from_string(
          app->m_kbd.xkb_ctx, (const char *)map, XKB_KEYMAP_FORMAT_TEXT_V1,
          XKB_KEYMAP_COMPILE_NO_FLAGS);
      app->m_kbd.xkb_state = app->m_kbd.xkb_keymap
                                 ? xkb_state_new(app->m_kbd.xkb_keymap)
                                 : nullptr;
      munmap(map, size);
      close(fd);
    };

    auto kb_enter = [](void *, wl_keyboard *, u32, wl_surface *,
                       wl_array *) -> void {};
    auto kb_leave = [](void *data, wl_keyboard *, u32, wl_surface *) -> void {
      auto *app = (App *)data;
      app->m_kbd.held.clear();
    };

    auto kb_key = [](void *data, wl_keyboard *, u32, u32, u32 key,
                     u32 state) -> void {
      auto *app = (App *)data;
      if (!app->m_kbd.xkb_state)
        return;

      xkb_keycode_t kc = key + 8;

      if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
        app->m_kbd.held.insert(key);

        xkb_state_update_key(app->m_kbd.xkb_state, kc, XKB_KEY_DOWN);
        xkb_keysym_t sym = xkb_state_key_get_one_sym(app->m_kbd.xkb_state, kc);
        app->m_kbd.pressed_syms.insert(sym);

        bool ctrl = app->m_kbd.mod_active("Control");
        bool alt = app->m_kbd.mod_active("Mod1");
        bool meta = app->m_kbd.mod_active("Mod4");
        if (!(ctrl || alt || meta)) {
          u32 cp = xkb_keysym_to_utf32(sym);
          if (cp >= 0x20) {
            char buf[8];
            int n = xkb_keysym_to_utf8(sym, buf, sizeof(buf));
            if (n > 0)
              app->m_kbd.typing.push_utf8(buf);
          }
        }
      } else {
        xkb_keysym_t sym = xkb_state_key_get_one_sym(app->m_kbd.xkb_state, kc);
        app->m_kbd.released_syms.insert(sym);

        app->m_kbd.held.erase(key);
        xkb_state_update_key(app->m_kbd.xkb_state, kc, XKB_KEY_UP);
      }
    };

    auto kb_mods = [](void *data, wl_keyboard *, u32, u32 depressed,
                      u32 latched, u32 locked, u32 group) -> void {
      auto *app = (App *)data;
      if (!app->m_kbd.xkb_state)
        return;
      xkb_state_update_mask(app->m_kbd.xkb_state, depressed, latched, locked, 0,
                            0, group);
    };

    auto kb_repeat_info = [](void *, wl_keyboard *, i32, i32) -> void {};

    keyboard_listener = {kb_keymap, kb_enter, kb_leave,
                         kb_key,    kb_mods,  kb_repeat_info};
  }

  auto handle_registry_global = [](void *data, wl_registry *registry, u32 name,
                                   const char *interface, u32 version) -> void {
    auto *app = static_cast<App *>(data);
    if (std::strcmp(interface, wl_compositor_interface.name) == 0) {
      app->m_wayland.compositor = static_cast<wl_compositor *>(
          wl_registry_bind(registry, name, &wl_compositor_interface, 4));
    } else if (strcmp(interface, wl_seat_interface.name) == 0) {
      app->m_wayland.seat = static_cast<wl_seat *>(
          wl_registry_bind(registry, name, &wl_seat_interface, 9));
      static struct wl_seat_listener const seat_listener = {
          .capabilities =
              [](void *data, struct wl_seat *seat, u32 caps) {
                auto *app = static_cast<App *>(data);
                if (caps & WL_SEAT_CAPABILITY_KEYBOARD) {
                  app->m_wayland.kbd = wl_seat_get_keyboard(seat);
                  wl_keyboard_add_listener(app->m_wayland.kbd,
                                           &keyboard_listener, data);
                }
              },
          .name = [](void *data, struct wl_seat *wl_seat, const char *name) {},
      };
      wl_seat_add_listener(app->m_wayland.seat, &seat_listener, data);
    } else if (strcmp(interface, zwlr_layer_shell_v1_interface.name) == 0) {
      app->m_wayland.layer_shell = (zwlr_layer_shell_v1 *)wl_registry_bind(
          registry, name, &zwlr_layer_shell_v1_interface,
          version >= 4 ? 4 : version);
    } else if (strcmp(interface,
                      ext_background_effect_manager_v1_interface.name) == 0) {
      app->m_wayland.mgr = (ext_background_effect_manager_v1 *)wl_registry_bind(
          registry, name, &ext_background_effect_manager_v1_interface, 1);
    } else if (strcmp(interface, "org_kde_kwin_blur_manager") == 0) {
      app->m_wayland.kde_blur_mgr =
          (org_kde_kwin_blur_manager *)wl_registry_bind(
              registry, name, &org_kde_kwin_blur_manager_interface, 1);
    }
  };

  static wl_registry_listener const registry_listener{
      .global = handle_registry_global,
      .global_remove = [](void *, wl_registry *, u32) {},
  };

  m_wayland.registry = wl_display_get_registry(m_wayland.display);
  wl_registry_add_listener(m_wayland.registry, &registry_listener, this);

  m_kbd.xkb_ctx = xkb_context_new(XKB_CONTEXT_NO_FLAGS);

  wl_display_roundtrip(m_wayland.display);

  create_layer_surface();
}

auto App::set_visible(bool visible) -> void {
  if (visible == m_visible)
    return;

  if (visible) {
    create_layer_surface();
    ensure_egl_surface();
  } else {
    destroy_layer_surface();
  }

  if (m_wayland.display)
    wl_display_flush(m_wayland.display);
}

auto App::init_egl() -> void {
  m_gl.edpy =
      eglGetDisplay(reinterpret_cast<EGLNativeDisplayType>(m_wayland.display));
  eglInitialize(m_gl.edpy, nullptr, nullptr);

  const EGLint cfgAttribs[]{
      EGL_SURFACE_TYPE,
      EGL_WINDOW_BIT,
      EGL_RENDERABLE_TYPE,
      EGL_OPENGL_ES2_BIT,
      EGL_RED_SIZE,
      8,
      EGL_GREEN_SIZE,
      8,
      EGL_BLUE_SIZE,
      8,
      EGL_ALPHA_SIZE,
      8,
      EGL_NONE,
  };
  EGLint n = 0;
  eglChooseConfig(m_gl.edpy, cfgAttribs, &m_gl.ecfg, 1, &n);

  const EGLint ctxAttribs[] = {EGL_CONTEXT_MAJOR_VERSION, 2, EGL_NONE};
  m_gl.ectx =
      eglCreateContext(m_gl.edpy, m_gl.ecfg, EGL_NO_CONTEXT, ctxAttribs);

  ensure_egl_surface();

  InitWindow(m_win_w, m_win_h, "");
}

auto App::init_signal() -> void {
  sigset_t mask;
  sigemptyset(&mask);
  sigaddset(&mask, SIGUSR1);

  if (pthread_sigmask(SIG_BLOCK, &mask, nullptr) != 0) {
    std::perror("pthread_sigmask");
    std::exit(EXIT_FAILURE);
  }

  m_sfd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
  if (m_sfd == -1) {
    std::perror("signalfd");
    std::exit(EXIT_FAILURE);
  }
}

void App::on_settings_changed(XdpSettings * /*self*/, const char *ns,
                              const char *key, GVariant * /*value*/,
                              gpointer data) {
  auto *app = static_cast<App *>(data);
  if (g_strcmp0(ns, "org.freedesktop.appearance") == 0 &&
      g_strcmp0(key, "color-scheme") == 0) {
    guint v = xdp_settings_read_uint(app->m_xdp.settings,
                                     "org.freedesktop.appearance",
                                     "color-scheme", NULL, NULL);

    if (v == 1)
      app->m_active_theme = Theme::Dark;
    else
      app->m_active_theme = Theme::Light;
  }
}

auto App::init_theme_portal() -> void {
  m_xdp.portal = xdp_portal_new();
  m_xdp.settings = xdp_portal_get_settings(m_xdp.portal);

  guint v = xdp_settings_read_uint(m_xdp.settings, "org.freedesktop.appearance",
                                   "color-scheme", NULL, NULL);
  if (v == 1)
    m_active_theme = Theme::Dark;
  else
    m_active_theme = Theme::Light;

  g_signal_connect(m_xdp.settings, "changed", G_CALLBACK(on_settings_changed),
                   this);
}

auto App::render_frame() -> void {
  if (!m_visible || m_gl.edpy == EGL_NO_DISPLAY || m_gl.esurf == EGL_NO_SURFACE)
    return;

  glViewport(0, 0, m_win_w, m_win_h);

  for (auto const cp : m_kbd.typing) {
    std::println("Char typed: {} ({})  shift={} ctrl={}", rune_to_string(cp),
                 cp, m_kbd.shift() ? 'y' : 'n', m_kbd.ctrl() ? 'y' : 'n');
  }

  if (m_kbd.is_sym_pressed(XKB_KEY_Escape)) {
    set_visible(!visible());
    if (m_kbd.ctrl() && m_kbd.shift()) {
      m_running = false;
    }
  }

  BeginDrawing();

  ClearBackground(BLANK);

  DrawFPS(10, 10);

  EndDrawing();

  eglSwapBuffers(m_gl.edpy, m_gl.esurf);
  m_kbd.typing.clear();
  m_kbd.clear_transients();
}

auto App::create_layer_surface() -> void {
  if (m_wayland.layer_surface)
    return;

  if (!m_wayland.compositor || !m_wayland.layer_shell)
    return;

  m_wayland.wl_surface = wl_compositor_create_surface(m_wayland.compositor);

  if (m_wayland.mgr) {
    m_wayland.eff = ext_background_effect_manager_v1_get_background_effect(
        m_wayland.mgr, m_wayland.wl_surface);
  }
  if (m_wayland.kde_blur_mgr) {
    m_wayland.kde_blur = org_kde_kwin_blur_manager_create(
        m_wayland.kde_blur_mgr, m_wayland.wl_surface);
  }

  m_wayland.layer_surface = zwlr_layer_shell_v1_get_layer_surface(
      m_wayland.layer_shell, m_wayland.wl_surface, nullptr,
      ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY, "waylight-overlay");

  if (!m_wayland.layer_surface) {
    if (m_wayland.eff) {
      ext_background_effect_surface_v1_destroy(m_wayland.eff);
      m_wayland.eff = nullptr;
    }
    if (m_wayland.kde_blur) {
      org_kde_kwin_blur_destroy(m_wayland.kde_blur);
      m_wayland.kde_blur = nullptr;
    }
    if (m_wayland.wl_surface) {
      wl_surface_destroy(m_wayland.wl_surface);
      m_wayland.wl_surface = nullptr;
    }
    return;
  }

  zwlr_layer_surface_v1_set_anchor(m_wayland.layer_surface, 0);
  zwlr_layer_surface_v1_set_size(m_wayland.layer_surface, m_win_w, m_win_h);
  zwlr_layer_surface_v1_set_exclusive_zone(m_wayland.layer_surface, 0);

  if (zwlr_layer_shell_v1_get_version(m_wayland.layer_shell) >= 3) {
    zwlr_layer_surface_v1_set_keyboard_interactivity(
        m_wayland.layer_surface,
        ZWLR_LAYER_SURFACE_V1_KEYBOARD_INTERACTIVITY_ON_DEMAND);
  }

  auto handle_layer_configure = [](void *data, zwlr_layer_surface_v1 *ls,
                                   u32 serial, u32 w, u32 h) -> void {
    auto *app = static_cast<App *>(data);
    if (w)
      app->m_win_w = static_cast<int>(w);
    if (h)
      app->m_win_h = static_cast<int>(h);

    zwlr_layer_surface_v1_ack_configure(ls, serial);

    if (app->m_gl.edpy != EGL_NO_DISPLAY) {
      if (!app->m_gl.wegl || app->m_gl.esurf == EGL_NO_SURFACE) {
        app->ensure_egl_surface();
      } else {
        wl_egl_window_resize(app->m_gl.wegl, app->m_win_w, app->m_win_h, 0, 0);
        eglMakeCurrent(app->m_gl.edpy, app->m_gl.esurf, app->m_gl.esurf,
                       app->m_gl.ectx);
      }
    }

    app->update_blur_region();

    if (app->m_wayland.wl_surface)
      wl_surface_commit(app->m_wayland.wl_surface);
  };

  auto handle_layer_closed = [](void *data, zwlr_layer_surface_v1 *) -> void {
    static_cast<App *>(data)->m_running = false;
  };

  static const zwlr_layer_surface_v1_listener lsl = {
      .configure = handle_layer_configure,
      .closed = handle_layer_closed,
  };

  zwlr_layer_surface_v1_add_listener(m_wayland.layer_surface, &lsl, this);

  update_blur_region();

  if (m_wayland.wl_surface)
    wl_surface_commit(m_wayland.wl_surface);

  if (m_wayland.display)
    wl_display_roundtrip(m_wayland.display);

  ensure_egl_surface();

  m_visible = true;
}

auto App::destroy_layer_surface() -> void {
  if (m_gl.edpy != EGL_NO_DISPLAY && m_gl.esurf != EGL_NO_SURFACE) {
    eglMakeCurrent(m_gl.edpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
    eglDestroySurface(m_gl.edpy, m_gl.esurf);
    m_gl.esurf = EGL_NO_SURFACE;
  }

  if (m_gl.wegl) {
    wl_egl_window_destroy(m_gl.wegl);
    m_gl.wegl = nullptr;
  }

  if (m_wayland.eff) {
    ext_background_effect_surface_v1_destroy(m_wayland.eff);
    m_wayland.eff = nullptr;
  }

  if (m_wayland.kde_blur) {
    org_kde_kwin_blur_destroy(m_wayland.kde_blur);
    m_wayland.kde_blur = nullptr;
  }

  if (m_wayland.layer_surface) {
    zwlr_layer_surface_v1_destroy(m_wayland.layer_surface);
    m_wayland.layer_surface = nullptr;
  }

  if (m_wayland.wl_surface) {
    wl_surface_destroy(m_wayland.wl_surface);
    m_wayland.wl_surface = nullptr;
  }

  if (m_wayland.display)
    wl_display_flush(m_wayland.display);

  m_visible = false;
}

auto App::ensure_egl_surface() -> void {
  if (m_gl.edpy == EGL_NO_DISPLAY || m_gl.ectx == EGL_NO_CONTEXT)
    return;
  if (!m_wayland.wl_surface)
    return;

  if (!m_gl.wegl)
    m_gl.wegl = wl_egl_window_create(m_wayland.wl_surface, m_win_w, m_win_h);

  if (!m_gl.wegl)
    return;

  if (m_gl.esurf == EGL_NO_SURFACE) {
    m_gl.esurf = eglCreateWindowSurface(
        m_gl.edpy, m_gl.ecfg, reinterpret_cast<EGLNativeWindowType>(m_gl.wegl),
        nullptr);
  }

  if (m_gl.esurf == EGL_NO_SURFACE)
    return;

  eglMakeCurrent(m_gl.edpy, m_gl.esurf, m_gl.esurf, m_gl.ectx);
  eglSwapInterval(m_gl.edpy, 1);
}

auto App::update_blur_region() -> void {
  if (!m_wayland.compositor)
    return;
  if (!m_wayland.eff && !m_wayland.kde_blur)
    return;

  wl_region *region = wl_compositor_create_region(m_wayland.compositor);
  if (!region)
    return;

  wl_region_add(region, 0, 0, m_win_w - 50, m_win_h);

  if (m_wayland.eff)
    ext_background_effect_surface_v1_set_blur_region(m_wayland.eff, region);
  if (m_wayland.kde_blur)
    org_kde_kwin_blur_set_region(m_wayland.kde_blur, region);

  wl_region_destroy(region);
}

auto App::pump_events() -> void {
  while (g_main_context_iteration(nullptr, false))
    ;

  wl_display_dispatch_pending(m_wayland.display);
  wl_display_flush(m_wayland.display);

  pollfd fds[2]{{wl_display_get_fd(m_wayland.display), POLLIN, 0},
                {m_sfd, POLLIN, 0}};

  auto prepared = (wl_display_prepare_read(m_wayland.display) == 0);
  auto ret = poll(fds, 2, 0);

  // Wayland
  if (ret > 0 && (fds[0].revents & POLLIN)) {
    if (prepared) {
      wl_display_read_events(m_wayland.display);
      prepared = false;
    }
  } else if (prepared) {
    wl_display_cancel_read(m_wayland.display);
  }

  // Signals
  if (ret > 0 && (fds[1].revents & POLLIN)) {
    signalfd_siginfo si;
    while (read(m_sfd, &si, sizeof(si)) == sizeof(si)) {
      if (si.ssi_signo == SIGUSR1) {
        set_visible(!visible());
      }
    }
  }
}

bool check_or_signal_running() {
  const char *lock_path = "/tmp/waylight.lock";
  int fd = open(lock_path, O_CREAT | O_RDWR, 0666);
  if (fd == -1)
    return false;

  if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
    FILE *f = fopen(lock_path, "r");
    if (f) {
      pid_t pid;
      if (fscanf(f, "%d", &pid) == 1)
        kill(pid, SIGUSR1);
      fclose(f);
    }
    close(fd);
    return true;
  }

  ftruncate(fd, 0);
  dprintf(fd, "%d\n", getpid());
  return false;
}

std::optional<App> g_app{};

auto main() -> int {
  if (check_or_signal_running()) {
    return 0;
  }

  std::signal(SIGINT, [](int) {
    if (g_app)
      g_app->stop();
  });

  g_app.emplace();
  g_app->run();
}