// -*- mode: c++; c-basic-offset: 2; -*-

#include "common.hh"

#include <gtk/gtk.h>
#include <memory>
#include <unordered_map>
#include <vector>

#include "gui_about.hh"
#include "gui_main.hh"
#include "gui_menu.hh"
#include "observers.hh"

namespace {

template<typename T>
class shared_gobject {
public:
  shared_gobject()
    : ptr_(nullptr) {
  }
  shared_gobject(std::nullptr_t)
    : ptr_(nullptr) {
  }
  explicit shared_gobject(T* ptr)
    : ptr_(ptr) {
  }
  shared_gobject(shared_gobject const& obj)
    : ptr_(obj.ptr_) {
    if (ptr_) g_object_ref(ptr_);
  }
  shared_gobject(shared_gobject&& obj)
    : ptr_(obj.ptr_) {
    obj.ptr = nullptr;
  }

  ~shared_gobject() {
    reset();
  }

  shared_gobject& operator=(shared_gobject const& obj) {
    reset(obj.ptr_);
    if (ptr_) g_object_ref(ptr_);
    return *this;
  }
  shared_gobject& operator=(shared_gobject&& obj) {
    ptr_ = obj.ptr_;
    obj.ptr_ = nullptr;
    return *this;
  }

  void swap(shared_gobject& obj) {
    auto x = ptr_;
    ptr_ = obj.ptr_;
    obj.ptr_ = x;
  }

  void reset() {
    if (ptr_) {
      g_object_unref(ptr_);
      ptr_ = nullptr;
    }
  }

  void reset(T* ptr) {
    if (ptr_) g_object_unref(ptr_);
    ptr_ = ptr;
  }

  T* get() const {
    return ptr_;
  }

  T& operator*() const {
    return *ptr_;
  }

  T* operator->() const {
    return ptr_;
  }

  explicit operator bool() const {
    return ptr_ != nullptr;
  }

private:
  T* ptr_;
};

#define MAIN_APP_TYPE main_app_get_type()

G_DECLARE_FINAL_TYPE(MainApp, main_app, MAIN, APP, GtkApplication)

#define MAIN_APP_WINDOW_TYPE main_app_window_get_type()
G_DECLARE_FINAL_TYPE(MainAppWindow, main_app_window, MAIN, APP_WINDOW,
                     GtkApplicationWindow)

class GtkGuiWindow : public GuiWindow {
public:
  GtkWindow* window() const {
    return reinterpret_cast<GtkWindow*>(impl());
  }

  void set_title(std::string const& title) override;
};

class GtkGuiMain : public virtual GuiMain, public GtkGuiWindow {
public:
  GtkGuiMain(std::string const& title, uint32_t width, uint32_t height)
    : title_(title), width_(width), height_(height) {
  }

  void set_menu(GuiMenu* menu) override {
    assert(menu);
    menu_ = menu;
  }

  GuiMenu* menu() const override {
    return menu_;
  }

  bool run(int argc, char** argv) override;

  bool exit() override;

  void set_title(std::string const& title) override;

  void show(GuiWindow* window) override;

  uint32_t default_width() const {
    return width_;
  }

  uint32_t default_height() const {
    return height_;
  }

  void add_listener(GuiMain::Listener* listener) override {
    observers_.insert(listener);
  }

  void remove_listener(GuiMain::Listener* listener) override {
    observers_.erase(listener);
  }

  void* impl() const override;

private:
  bool notify_about_to_exit() {
    auto it = observers_.notify();
    while (it.has_next()) {
      if (!it.next()->about_to_exit()) return false;
    }
    return true;
  }

  std::string title_;
  uint32_t width_;
  uint32_t height_;

  shared_gobject<MainApp> app_;
  Observers<GuiMain::Listener*> observers_;
  GuiMenu* menu_;
};

class GtkGuiMenu : public GuiMenu {
public:
  GtkGuiMenu()
    : parent_(nullptr), menu_(g_menu_new()), map_(nullptr) {
  }

  ~GtkGuiMenu() override {
  }

  void add_listener(Listener* listener) override {
    if (parent_) {
      parent_->add_listener(listener);
      return;
    }
    observers_.insert(listener);
  }

  void remove_listener(Listener* listener) override {
    if (parent_) {
      parent_->remove_listener(listener);
      return;
    }
    observers_.erase(listener);
  }

  GMenuModel* model() const {
    return G_MENU_MODEL(menu_.get());
  }

  void set_map(GActionMap* map);
  void activate(GSimpleAction* action);

  void add_item(std::string const& id, std::string const& label) override;
  GuiMenu* add_menu(std::string const& label) override;
  bool enable_item(std::string const& id, bool enable) override;

private:
  explicit GtkGuiMenu(GtkGuiMenu* parent)
    : parent_(parent), menu_(g_menu_new()), map_(nullptr) {
  }

  void notify_item_activated(std::string const& id) {
    auto it = observers_.notify();
    while (it.has_next()) {
      it.next()->item_activated(id);
    }
  }

  std::string add_action(std::string const& id);
  std::string escape(std::string const& id);
  std::string unescape(std::string const& action);

  GtkGuiMenu* const parent_;
  shared_gobject<GMenu> menu_;
  std::unordered_map<std::string, shared_gobject<GSimpleAction>> action_;
  GActionMap* map_;
  std::vector<std::unique_ptr<GtkGuiMenu>> submenus_;
  Observers<Listener*> observers_;
};

void close_about_dialog(GtkAboutDialog* about) {
  // TODO: Restore dialog state
  gtk_widget_hide(GTK_WIDGET(about));
}

class GtkGuiAbout : public virtual GuiAbout, public GtkGuiWindow {
public:
  GtkGuiAbout(std::string const& title, std::string const& version,
              std::vector<std::string> const& authors)
    : about_(GTK_ABOUT_DIALOG(gtk_about_dialog_new())) {
    gtk_about_dialog_set_program_name(about_, title.c_str());
    gtk_about_dialog_set_version(about_, version.c_str());
    std::vector<std::string> tmp;
    tmp.reserve(authors.size() / 2);
    for (size_t i = 0; i < authors.size(); i += 2) {
      if (authors[i + 1].empty()) {
        tmp.push_back(authors[i]);
      } else {
        tmp.push_back(authors[i] + " <" + authors[i + 1] + ">");
      }
    }
    std::vector<gchar const*> tmp2;
    tmp2.reserve(tmp.size() + 1);
    for (auto const& str : tmp) tmp2.push_back(str.c_str());
    tmp2.push_back(nullptr);
    gtk_about_dialog_set_authors(about_, tmp2.data());

    g_signal_connect(about_, "delete-event",
                     G_CALLBACK(gtk_widget_hide_on_delete), nullptr);
    g_signal_connect(about_, "response",
                     G_CALLBACK(close_about_dialog), nullptr);
  }

  ~GtkGuiAbout() override {
    gtk_widget_destroy(GTK_WIDGET(about_));
  }

  void* impl() const override {
    return about_;
  }

  void set_title(std::string const& title) override {
    GtkGuiWindow::set_title(title);
  }

  void add_listener(GuiAbout::Listener* listener) override {
    observers_.insert(listener);
  }

  void remove_listener(GuiAbout::Listener* listener) override {
    observers_.erase(listener);
  }

private:
  GtkAboutDialog* about_;
  Observers<GuiAbout::Listener*> observers_;
};

struct _MainApp
{
  GtkApplication parent;
  GtkGuiMain* main;
};

struct _MainAppWindow
{
  GtkApplicationWindow parent;
};

G_DEFINE_TYPE(MainApp, main_app, GTK_TYPE_APPLICATION);

G_DEFINE_TYPE(MainAppWindow, main_app_window, GTK_TYPE_APPLICATION_WINDOW);

MainAppWindow* main_app_window_new(MainApp *app) {
  auto ret = MAIN_APP_WINDOW(g_object_new(MAIN_APP_WINDOW_TYPE,
                                          "application", app, nullptr));
  gtk_window_set_default_size(GTK_WINDOW(ret), app->main->default_width(),
                              app->main->default_height());
  return ret;
}

void main_app_activate(GApplication* g_app) {
  auto app = MAIN_APP(g_app);
  auto menu = static_cast<GtkGuiMenu*>(app->main->menu());
  if (menu) {
    menu->set_map(G_ACTION_MAP(app));
    gtk_application_set_menubar(GTK_APPLICATION(app), menu->model());
  }
  auto win = main_app_window_new(app);
  gtk_window_present(GTK_WINDOW(win));
}

void main_app_window_open(MainAppWindow* win, GFile* file) {
}

void main_app_open(GApplication* app, GFile** files, gint n_files,
                   gchar const* hint) {
  auto windows = gtk_application_get_windows(GTK_APPLICATION(app));
  auto win = windows ? MAIN_APP_WINDOW(windows->data)
    : main_app_window_new(MAIN_APP(app));

  for (auto i = 0; i < n_files; i++) {
    main_app_window_open(win, files[i]);
  }

  gtk_window_present(GTK_WINDOW(win));
}

void main_app_class_init(MainAppClass* clazz) {
  G_APPLICATION_CLASS(clazz)->activate = main_app_activate;
  G_APPLICATION_CLASS(clazz)->open = main_app_open;
}

void main_app_window_init(MainAppWindow* app) {
}

void main_app_window_class_init(MainAppWindowClass* clazz) {
}

MainApp* main_app_new(GtkGuiMain* main) {
  auto ret = MAIN_APP(g_object_new(MAIN_APP_TYPE,
                                   "application-id", "org.jk.tp",
                                   "flags", G_APPLICATION_HANDLES_OPEN,
                                   nullptr));
  ret->main = main;
  return ret;
}

void GtkGuiWindow::set_title(std::string const& title) {
  auto win = window();
  if (!win) return;
  gtk_window_set_title(win, title.c_str());
}

bool GtkGuiMain::run(int argc, char** argv) {
  app_.reset(main_app_new(this));
  return g_application_run(G_APPLICATION(app_.get()), argc, argv);
}

void* GtkGuiMain::impl() const {
  if (!app_) return nullptr;
  auto windows = gtk_application_get_windows(GTK_APPLICATION(app_.get()));
  if (!windows) return nullptr;
  return windows->data;
}

void GtkGuiMain::set_title(std::string const& title) {
  title_ = title;
  GtkGuiWindow::set_title(title);
}

bool GtkGuiMain::exit() {
  if (!app_) {
    assert(false);
    return true;
  }
  if (!notify_about_to_exit()) return false;
  g_application_quit(G_APPLICATION(app_.get()));
  return true;
}

void GtkGuiMain::show(GuiWindow* window) {
  auto wnd = reinterpret_cast<GtkWindow*>(window->impl());
  if (!wnd) {
    assert(false);
    return;
  }
  gtk_window_set_transient_for(wnd, this->window());
  gtk_window_present(wnd);
}

void GtkGuiMenu::add_item(std::string const& id, std::string const& label) {
  auto action = add_action(id);
  g_menu_append(menu_.get(), label.c_str(), action.c_str());
}

GuiMenu* GtkGuiMenu::add_menu(std::string const& label) {
  auto ret = new GtkGuiMenu(this);
  g_menu_append_submenu(menu_.get(), label.c_str(), ret->model());
  submenus_.emplace_back(ret);
  return ret;
}

void GtkGuiMenu::set_map(GActionMap* map) {
  assert(!parent_);
  assert(!map_);
  assert(map);
  map_ = map;
  for (auto const& pair : action_) {
    g_action_map_add_action(map_, G_ACTION(pair.second.get()));
  }
}

std::string GtkGuiMenu::escape(std::string const& action) {
  // TODO
  return action;
}

std::string GtkGuiMenu::unescape(std::string const& action) {
  return action;
}

void menu_item_activate(GSimpleAction* action, GVariant* parameter,
                        gpointer* data) {
  auto menu = reinterpret_cast<GtkGuiMenu*>(data);
  menu->activate(action);
}

void GtkGuiMenu::activate(GSimpleAction* action) {
  notify_item_activated(unescape(g_action_get_name(G_ACTION(action))));
}

std::string GtkGuiMenu::add_action(std::string const& id) {
  if (parent_) return parent_->add_action(id);
  std::string name = escape(id);
  auto action = g_simple_action_new(name.c_str(), nullptr);
  action_.emplace(id, action);
  g_signal_connect(action, "activate", G_CALLBACK(menu_item_activate), this);
  if (map_) g_action_map_add_action(map_, G_ACTION(action));
  return "app." + name;
}

bool GtkGuiMenu::enable_item(std::string const& id, bool enable) {
  if (parent_) return parent_->enable_item(id, enable);
  auto pair = action_.find(id);
  if (pair == action_.end()) return false;
  g_simple_action_set_enabled(pair->second.get(), enable);
  return true;
}

}  // namespace

// static
GuiMain* GuiMain::create(std::string const& title, uint32_t width,
                         uint32_t height) {
  return new GtkGuiMain(title, width, height);
}

// static
GuiMenu* GuiMenu::create() {
  return new GtkGuiMenu();
}

// static
GuiAbout* GuiAbout::create(std::string const& title,
                           std::string const& version,
                           char const* author_name,
                           char const* author_email,
                           ...) {
  std::vector<std::string> authors;
  authors.push_back(author_name);
  authors.push_back(author_email);
  va_list args;
  va_start(args, author_email);
  while (true) {
    auto name = va_arg(args, char const*);
    if (!name) break;
    auto email = va_arg(args, char const*);
    authors.push_back(name);
    authors.push_back(email);
  }
  va_end(args);
  return new GtkGuiAbout(title, version, authors);
}