/* Copyright (C) 2007 The gtkmm Development Team
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <gio/gio.h>
#include <giomm/file.h>
#include <giomm/actiongroup.h>
#include <giomm/init.h>
#include <cstring> // std::memset()
#include <map>
#include <mutex>
#include <vector>
#include <forward_list>

using Flags = Gio::Application::Flags;

namespace // anonymous
{
// The function pointer, Application_signal_open_funcptr, is set in
// Application_Class::class_init_function() (generated by gmmproc), making it
// possible to indirectly call an Application_Class member function from
// a function with C linkage.
using Application_signal_open_functype = void (*) (GApplication* self, GFile** files, gint n_files, const gchar* hint);
Application_signal_open_functype Application_signal_open_funcptr;

extern "C"
{
// Shall be static. Non-static functions with C linkage get external linkage,
// even if they are defined in an anonymous namespace.
static void
Application_signal_open_default_callback(GApplication* self, GFile** files, gint n_files, const gchar* hint)
{
  Application_signal_open_funcptr(self, files, n_files, hint);
}

static void
Application_signal_open_connect_callback(
  GApplication* self, GFile** files, gint n_files, const gchar* hint, void* data)
{
  using SlotType = sigc::slot<void(const Gio::Application::type_vec_files&, const Glib::ustring&)>;

  Gio::Application::type_vec_files vec_files(n_files);
  for (int i = 0; i < n_files; ++i)
  {
    vec_files[i] = Glib::wrap(files[i], true);
  }

  const auto hint_str = (hint ? hint : Glib::ustring());

  // Do not try to call a signal on a disassociated wrapper.
  if (Glib::ObjectBase::_get_current_wrapper((GObject*)self))
  {
    try
    {
      if (const auto slot = Glib::SignalProxyNormal::data_to_slot(data))
      {
        (*static_cast<SlotType*>(slot))(vec_files, hint_str);
        return;
      }
    }
    catch (...)
    {
      Glib::exception_handlers_invoke();
    }
  }

  return;
}

static void
Application_signal_open_notify_callback(
  GApplication* self, GFile** files, gint n_files, const gchar* hint, void* data)
{
  using namespace Gio;
  using SlotType = sigc::slot<void(const Application::type_vec_files&, const Glib::ustring&)>;

  Application::type_vec_files vec_files(n_files);
  for (int i = 0; i < n_files; i++)
  {
    vec_files[i] = Glib::wrap(files[i], true);
  }

  const auto hint_str = (hint ? hint : Glib::ustring());

  // Do not try to call a signal on a disassociated wrapper.
  if (Glib::ObjectBase::_get_current_wrapper((GObject*)self))
  {
    try
    {
      if (const auto slot = Glib::SignalProxyNormal::data_to_slot(data))
      {
        (*static_cast<SlotType*>(slot))(vec_files, hint_str);
        return;
      }
    }
    catch (...)
    {
      Glib::exception_handlers_invoke();
    }
  }

  return;
}
} // extern "C"

static const Glib::SignalProxyInfo Application_signal_open_info = { "open",
  (GCallback)&Application_signal_open_connect_callback,
  (GCallback)&Application_signal_open_notify_callback };

// The add_main_option_entry*() methods that take a slot parameter are handled
// similarly to the corresponding Glib::OptionGroup::add_entry*() methods.
// There is an important difference: In add_main_option_entry*() we can't pass
// an Application pointer to the used GOptionGroup.
// g_application_add_main_option_entries() creates a GOptionGroup with user_data == nullptr.
// Therefore Application_option_arg_callback() is called with data == nullptr.
// Application_option_arg_callback() does not know which Application instance
// the command-line option belongs to. All Application instances (usually only one)
// share a map, mapping the long command option name to an OptionArgCallbackData.
class OptionArgCallbackData
{
public:
  explicit OptionArgCallbackData(const Gio::Application* application,
    const Glib::ustring& long_name, gchar short_name,
    const Glib::ustring& description, const Glib::ustring& arg_description,
    const Glib::OptionGroup::SlotOptionArgString& slot)
  :
    application_(application),
    long_name_(g_strdup(long_name.c_str())), // must not be nullptr
    short_name_(short_name),
    description_(g_strdup(Glib::c_str_or_nullptr(description))),
    arg_description_(g_strdup(Glib::c_str_or_nullptr(arg_description))),
    slot_string_(new Glib::OptionGroup::SlotOptionArgString(slot)),
    slot_filename_(nullptr)
  {
  }

  explicit OptionArgCallbackData(const Gio::Application* application,
    const Glib::ustring& long_name, gchar short_name,
    const Glib::ustring& description, const Glib::ustring& arg_description,
    const Glib::OptionGroup::SlotOptionArgFilename& slot)
  :
    application_(application),
    long_name_(g_strdup(long_name.c_str())), // must not be nullptr
    short_name_(short_name),
    description_(g_strdup(Glib::c_str_or_nullptr(description))),
    arg_description_(g_strdup(Glib::c_str_or_nullptr(arg_description))),
    slot_string_(nullptr),
    slot_filename_(new Glib::OptionGroup::SlotOptionArgFilename(slot))
  {
  }

  const Gio::Application* get_application() const { return application_; }
  const gchar* get_long_name() const { return long_name_; }
  gchar get_short_name() const { return short_name_; }
  const gchar* get_description() const { return description_; }
  const gchar* get_arg_description() const { return arg_description_; }
  bool is_filename_option() const { return slot_filename_ != nullptr; }

  const Glib::OptionGroup::SlotOptionArgString* get_slot_string() const { return slot_string_; }

  const Glib::OptionGroup::SlotOptionArgFilename* get_slot_filename() const
  {
    return slot_filename_;
  }

  ~OptionArgCallbackData()
  {
    g_free(long_name_);
    g_free(description_);
    g_free(arg_description_);
    delete slot_string_;
    delete slot_filename_;
    // Don't delete application_. It's not owned by this class.
  }

private:
  const Gio::Application* application_;
  gchar* long_name_;
  gchar short_name_;
  gchar* description_;
  gchar* arg_description_;
  // One of these slot pointers is nullptr and the other one points to a slot.
  Glib::OptionGroup::SlotOptionArgString* slot_string_;
  Glib::OptionGroup::SlotOptionArgFilename* slot_filename_;

  // Not copyable
  OptionArgCallbackData(const OptionArgCallbackData&) = delete;
  OptionArgCallbackData& operator=(const OptionArgCallbackData&) = delete;

}; // end class OptionArgCallbackData

using OptionArgCallbackDataMap = std::map<Glib::ustring, OptionArgCallbackData*>;
OptionArgCallbackDataMap option_arg_callback_data;

// Gio::Application instances may be used in different threads.
// Accesses to option_arg_callback_data and option_strings must be thread-safe.
std::mutex option_arg_callback_data_mutex;

extern "C"
{
static gboolean
Application_option_arg_callback(
  const gchar* option_name, const gchar* value, gpointer /* data */, GError** error)
{
  const Glib::ustring cpp_option_name(option_name);

  // option_name is either a single dash followed by a single letter (for a
  // short name) or two dashes followed by a long option name.
  std::unique_lock<std::mutex> lock(option_arg_callback_data_mutex);
  OptionArgCallbackDataMap::const_iterator iterFind = option_arg_callback_data.end();
  if (option_name[1] == '-')
  {
    // Long option name.
    const auto long_option_name = Glib::ustring(option_name + 2);
    iterFind = option_arg_callback_data.find(long_option_name);
  }
  else
  {
    // Short option name.
    const auto short_option_name = option_name[1];
    for (iterFind = option_arg_callback_data.begin(); iterFind != option_arg_callback_data.end();
         ++iterFind)
    {
      if (iterFind->second->get_short_name() == short_option_name)
        break;
    }
  }

  if (iterFind == option_arg_callback_data.end())
  {
    Glib::OptionError(Glib::OptionError::UNKNOWN_OPTION, "Application_option_arg_callback(): "
                                                         "Unknown option " +
                                                           cpp_option_name)
      .propagate(error);
    return false;
  }

  const bool has_value = (value != nullptr);
  const OptionArgCallbackData* const option_arg = iterFind->second;
  try
  {
    if (option_arg->is_filename_option())
    {
      const auto the_slot = option_arg->get_slot_filename();
      lock.unlock();
      const std::string cpp_value(value ? value : "");
      return (*the_slot)(cpp_option_name, cpp_value, has_value);
    }
    else
    {
      const auto the_slot = option_arg->get_slot_string();
      lock.unlock();
      const Glib::ustring cpp_value(value ? value : "");
      return (*the_slot)(cpp_option_name, cpp_value, has_value);
    }
  }
  catch (Glib::Error& err)
  {
    err.propagate(error);
  }
  catch (...)
  {
    Glib::exception_handlers_invoke();
  }
  return false;
}
} // extern "C"

// Compare with the definition of Glib::make_unique_ptr_gfree().
using UniquePtrStrType = std::unique_ptr<gchar[], decltype(&g_free)>;
using StrList = std::forward_list<UniquePtrStrType>;
using StrListMap = std::map<Gio::Application*, StrList>;
StrListMap option_strings;

} // anonymous namespace

namespace Gio
{

const Glib::Class&
Application::custom_class_init()
{
  Glib::init();
  Gio::init();
  return application_class_.init();
}

Application::Application(const Glib::ustring& application_id, Flags flags)
: // Mark this class as non-derived to allow C++ vfuncs to be skipped.
  // GApplication complains about "" but allows nullptr, so we avoid passing "".
  Glib::ObjectBase(nullptr),
  Glib::Object(Glib::ConstructParams(custom_class_init(),
    "application_id", Glib::c_str_or_nullptr(application_id),
    "flags", static_cast<GApplicationFlags>(flags), nullptr))
{
}

Application::~Application() noexcept
{
  // Delete all OptionArgCallbackData instances that belong to this application.
  std::lock_guard<std::mutex> lock(option_arg_callback_data_mutex);
  OptionArgCallbackDataMap::iterator iter = option_arg_callback_data.begin();
  while (iter != option_arg_callback_data.end())
  {
    OptionArgCallbackDataMap::iterator saved_iter = iter;
    ++iter;
    if (saved_iter->second->get_application() == this)
    {
      delete saved_iter->second;
      option_arg_callback_data.erase(saved_iter);
    }
  }

  // Delete the StrList that belongs to this application.
  option_strings.erase(this);
}

// static
void
Application::unset_default()
{
  g_application_set_default(nullptr);
}

void
Application_Class::open_callback(GApplication* self, GFile** files, gint n_files, const gchar* hint)
{
  const auto obj_base =
    static_cast<Glib::ObjectBase*>(Glib::ObjectBase::_get_current_wrapper((GObject*)self));

  // Non-gtkmmproc-generated custom classes implicitly call the default
  // Glib::ObjectBase constructor, which sets is_derived_. But gtkmmproc-
  // generated classes can use this optimisation, which avoids the unnecessary
  // parameter conversions if there is no possibility of the virtual function
  // being overridden:

  if (obj_base && obj_base->is_derived_())
  {
    const auto obj = dynamic_cast<CppObjectType* const>(obj_base);
    if (obj) // This can be nullptr during destruction.
    {
      try // Trap C++ exceptions which would normally be lost because this is a C callback.
      {
        // Call the virtual member method, which derived classes might override.
        Application::type_vec_files vec_files(n_files);
        for (int i = 0; i < n_files; i++)
        {
          vec_files[i] = Glib::wrap(files[i], true);
        }

        const auto hint_str = (hint ? hint : Glib::ustring());

        obj->on_open(vec_files, hint_str);
        return;
      }
      catch (...)
      {
        Glib::exception_handlers_invoke();
      }
    }
  }

  const auto base = static_cast<BaseClassType*>(g_type_class_peek_parent(G_OBJECT_GET_CLASS(
    self)) // Get the parent class of the object class (The original underlying C class).
    );

  // Call the original underlying C function:
  if (base && base->open)
    (*base->open)(self, files, n_files, hint);
}

Glib::SignalProxy<void(const Application::type_vec_files&, const Glib::ustring&)>
Application::signal_open()
{
  return Glib::SignalProxy<void(const Application::type_vec_files&, const Glib::ustring&)>(
    this, &Application_signal_open_info);
}

void
Gio::Application::on_open(const Application::type_vec_files& files, const Glib::ustring& hint)
{
  const auto base = static_cast<BaseClassType*>(g_type_class_peek_parent(G_OBJECT_GET_CLASS(
    gobject_)) // Get the parent class of the object class (The original underlying C class).
    );

  if (base && base->open)
  {
    (*base->open)(gobj(),
      Glib::ArrayHandler<type_vec_files::value_type>::vector_to_array(files).data(), files.size(),
      hint.c_str());
  }
}

void
Application::open(const type_vec_files& files, const Glib::ustring& hint)
{
  g_application_open(gobj(),
    Glib::ArrayHandler<type_vec_files::value_type>::vector_to_array(files).data(), files.size(),
    hint.c_str());
}

void
Application::open(const Glib::RefPtr<Gio::File>& file, const Glib::ustring& hint)
{
  type_vec_files files(1);
  files[0] = file;
  open(files, hint);
}

void
Application::add_main_option_entry(OptionType arg_type, const Glib::ustring& long_name,
  gchar short_name, const Glib::ustring& description, const Glib::ustring& arg_description,
  Glib::OptionEntry::Flags flags)
{
  // g_application_add_main_option() is not used, because it does not accept
  // description == nullptr. See https://gitlab.gnome.org/GNOME/glibmm/-/issues/124

  // Create a temporary array, just so we can give the correct thing to
  // g_application_add_main_option_entries():
  GOptionEntry array[2];
  std::memset(array, 0, 2 * sizeof(GOptionEntry)); // null-termination

  // g_application_add_main_option_entries() does not take its own copy
  // of the strings. We must keep them alive, and keep pointers to them,
  // so we can delete them when the Application instance is deleted.

  gchar* long_name_copy = g_strdup(long_name.c_str()); // must not be nullptr
  gchar* description_copy = g_strdup(Glib::c_str_or_nullptr(description));
  gchar* arg_description_copy = g_strdup(Glib::c_str_or_nullptr(arg_description));
  {
    std::lock_guard<std::mutex> lock(option_arg_callback_data_mutex);
    auto& application_str_list = option_strings[this];
    application_str_list.emplace_front(long_name_copy, g_free);
    if (description_copy)
      application_str_list.emplace_front(description_copy, g_free);
    if (arg_description_copy)
      application_str_list.emplace_front(arg_description_copy, g_free);
  } // option_arg_callback_data_mutex.unlock()

  // Fill in array[0].
  array[0].arg = static_cast<GOptionArg>(arg_type);
  array[0].long_name = long_name_copy;
  array[0].short_name = short_name;
  array[0].description = description_copy;
  array[0].arg_description = arg_description_copy;
  array[0].flags = static_cast<int>(flags);

  g_application_add_main_option_entries(gobj(), array);
}

void
Application::add_main_option_entry(const Glib::OptionGroup::SlotOptionArgString& slot,
  const Glib::ustring& long_name, gchar short_name, const Glib::ustring& description,
  const Glib::ustring& arg_description, Glib::OptionEntry::Flags flags)
{
  OptionArgCallbackData* callback_data = nullptr;
  {
    std::lock_guard<std::mutex> lock(option_arg_callback_data_mutex);
    OptionArgCallbackDataMap::iterator iterFind = option_arg_callback_data.find(long_name);
    if (iterFind != option_arg_callback_data.end())
      return; // Ignore duplicates

    callback_data = new OptionArgCallbackData(
      this, long_name, short_name, description, arg_description, slot);
    option_arg_callback_data[long_name] = callback_data;
  } // option_arg_callback_data_mutex.unlock()

  add_main_option_entry_private(callback_data->get_long_name(), short_name,
    callback_data->get_description(), callback_data->get_arg_description(),
    flags & ~Glib::OptionEntry::Flags::FILENAME);
}

void
Application::add_main_option_entry_filename(const Glib::OptionGroup::SlotOptionArgFilename& slot,
  const Glib::ustring& long_name, gchar short_name, const Glib::ustring& description,
  const Glib::ustring& arg_description, Glib::OptionEntry::Flags flags)
{
  OptionArgCallbackData* callback_data = nullptr;
  {
    std::lock_guard<std::mutex> lock(option_arg_callback_data_mutex);
    OptionArgCallbackDataMap::iterator iterFind = option_arg_callback_data.find(long_name);
    if (iterFind != option_arg_callback_data.end())
      return; // Ignore duplicates

    callback_data = new OptionArgCallbackData(
      this, long_name, short_name, description, arg_description, slot);
    option_arg_callback_data[long_name] = callback_data;
  } // option_arg_callback_data_mutex.unlock()

  add_main_option_entry_private(callback_data->get_long_name(), short_name,
    callback_data->get_description(), callback_data->get_arg_description(),
    flags | Glib::OptionEntry::Flags::FILENAME);
}

void
Application::add_main_option_entry_private(const gchar* long_name,
  gchar short_name, const gchar* description,
  const gchar* arg_description, Glib::OptionEntry::Flags flags)
{
  // g_application_add_main_option() can't be used for options with
  // a callback slot, because GOptionEntry.arg_data must be non-null.

  // Create a temporary array, just so we can give the correct thing to
  // g_application_add_main_option_entries():
  GOptionEntry array[2];
  std::memset(array, 0, 2 * sizeof(GOptionEntry)); // null-termination

  // g_application_add_main_option_entries() does not take its own copy
  // of the strings. We must keep them alive, and keep pointers to them,
  // so we can delete them when the Application instance is deleted.
  // This is handled in OptionArgCallbackData.

  // Fill in array[0].
  array[0].arg = G_OPTION_ARG_CALLBACK;
  array[0].long_name = long_name;
  array[0].short_name = short_name;
  array[0].description = description;
  array[0].arg_description = arg_description;
  array[0].flags = static_cast<int>(flags);

  // GoptionEntry.arg_data is a function pointer, cast to void*.
  // See Glib::OptionGroup::CppOptionEntry::allocate_c_arg() for a discussion
  // of this hack.
  union {
    void* dp;
    GOptionArgFunc fp;
  } u;
  u.fp = &Application_option_arg_callback;
  array[0].arg_data = u.dp;

  g_application_add_main_option_entries(gobj(), array);
}

void
Application::unset_resource_base_path()
{
  g_application_set_resource_base_path(gobj(), nullptr /* see the C docs. */);
}

} // namespace Gio
