// -*- Mode: C++; indent-tabs-mode: nil; tab-width: 2 -*-
/*
* Copyright (C) 2010, 2011 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Neil Jagdish Patel <neil.patel@canonical.com>
*/

#include "IconLoader.h"
#include "config.h"

#include <queue>
#include <sstream>
#include <boost/algorithm/string.hpp>
#include <unity-protocol.h>
#include <pango/pango.h>
#include <pango/pangocairo.h>

#include <Nux/Nux.h>
#include <NuxCore/Logger.h>
#include <NuxGraphics/CairoGraphics.h>
#include <UnityCore/ConnectionManager.h>
#include <UnityCore/GLibSource.h>
#include <UnityCore/GLibWrapper.h>

#include "unity-shared/Timer.h"
#include "unity-shared/ThemeSettings.h"
#include "unity-shared/UnitySettings.h"

namespace unity
{
DECLARE_LOGGER(logger, "unity.iconloader");
namespace
{
const int MIN_ICON_SIZE = 2;
const int RIBBON_PADDING = 2;
}

class IconLoader::Impl
{
public:
  static const int FONT_SIZE = 8;
  static const int MIN_FONT_SIZE = 5;

  Impl();

  Handle LoadFromIconName(std::string const&, int max_width, int max_height, IconLoaderCallback const& slot);
  Handle LoadFromGIconString(std::string const&, int max_width, int max_height, IconLoaderCallback const& slot);
  Handle LoadFromFilename(std::string const&, int max_width, int max_height, IconLoaderCallback const& slot);
  Handle LoadFromThemedFilename(std::string const&, int max_width, int max_height, IconLoaderCallback const& slot);
  Handle LoadFromURI(std::string const&, int max_width, int max_height, IconLoaderCallback const& slot);

  void DisconnectHandle(Handle);

  static void CalculateTextHeight(int* width, int* height);

private:

  enum IconLoaderRequestType
  {
    REQUEST_TYPE_ICON_NAME = 0,
    REQUEST_TYPE_GICON_STRING,
    REQUEST_TYPE_URI,
  };

  struct IconLoaderTask
  {
    typedef std::shared_ptr<IconLoaderTask> Ptr;

    IconLoaderRequestType type;
    std::string data;
    int max_width;
    int max_height;
    std::string key;
    IconLoaderCallback slot;
    Handle handle;
    Impl* impl;
    glib::Object<GtkIconInfo> icon_info;
    bool no_cache;
    Handle helper_handle;
    std::list<IconLoaderTask::Ptr> shadow_tasks;
    glib::Object<GdkPixbuf> result;
    glib::Error error;
    glib::SourceManager idles;

    IconLoaderTask(IconLoaderRequestType type_,
                   std::string const& data_,
                   int max_width_,
                   int max_height_,
                   std::string const& key_,
                   IconLoaderCallback const& slot_,
                   Handle handle_,
                   Impl* self_)
      : type(type_), data(data_), max_width(max_width_)
      , max_height(max_height_), key(key_)
      , slot(slot_), handle(handle_), impl(self_)
      , no_cache(false), helper_handle(0)
      {}

    ~IconLoaderTask()
    {
      if (helper_handle != 0)
        impl->DisconnectHandle(helper_handle);
    }

    void InvokeSlot()
    {
      if (slot)
        slot(data, max_width, max_height, result);

      // notify shadow tasks
      for (auto shadow_task : shadow_tasks)
      {
        if (shadow_task->slot)
          shadow_task->slot(shadow_task->data,
                            shadow_task->max_width,
                            shadow_task->max_height,
                            result);

        impl->task_map_.erase(shadow_task->handle);
      }

      shadow_tasks.clear();
    }

    bool Process()
    {
      // Check the cache again, as previous tasks might have wanted the same
      if (impl->CacheLookup(key, data, max_width, max_height, slot))
        return true;

      LOG_DEBUG(logger) << "Processing  " << data << " at size " << max_height;

      // Rely on the compiler to tell us if we miss a new type
      switch (type)
      {
        case REQUEST_TYPE_ICON_NAME:
          return ProcessIconNameTask();
        case REQUEST_TYPE_GICON_STRING:
          return ProcessGIconTask();
        case REQUEST_TYPE_URI:
          return ProcessURITask();
      }

      LOG_WARNING(logger) << "Request type " << type
                          << " is not supported (" << data
                          << " " << max_width << "x" << max_height << ")";
      result = nullptr;
      InvokeSlot();

      return true;
    }

    bool ProcessIconNameTask()
    {
      int size = max_height < 0 ? max_width : (max_width < 0 ? max_height : MIN(max_height, max_width));
      GtkIconInfo *info = ::gtk_icon_theme_lookup_icon(impl->theme_, data.c_str(),
                                                       size, GTK_ICON_LOOKUP_FORCE_SIZE);
      if (info)
      {
        icon_info = info;
        PushSchedulerJob();

        return false;
      }
      else
      {
        LOG_WARNING(logger) << "Unable to load icon " << data
                            << " at size " << size;
      }

      result = nullptr;
      InvokeSlot();

      return true;
    }

    bool ProcessGIconTask()
    {
      glib::Error error;
      glib::Object<GIcon> icon(::g_icon_new_for_string(data.c_str(), &error));
      int size = max_height < 0 ? max_width : (max_width < 0 ? max_height : MIN(max_height, max_width));

      if (icon.IsType(UNITY_PROTOCOL_TYPE_ANNOTATED_ICON))
      {
        glib::Object<UnityProtocolAnnotatedIcon> anno(glib::object_cast<UnityProtocolAnnotatedIcon>(icon));
        GIcon* base_icon = unity_protocol_annotated_icon_get_icon(anno);
        glib::String gicon_string(g_icon_to_string(base_icon));

        // ensure that annotated icons aren't cached by the IconLoader
        no_cache = true;

        auto helper_slot = sigc::bind(sigc::mem_fun(this, &IconLoaderTask::BaseIconLoaded), anno);
        int base_icon_width, base_icon_height;
        if (unity_protocol_annotated_icon_get_use_small_icon(anno))
        {
          // FIXME: although this pretends to be generic, we're just making
          // sure that icons requested to have 96px will be 64
          base_icon_width = max_width > 0 ? max_width * 2 / 3 : max_width;
          base_icon_height = max_height > 0 ? max_height * 2 / 3 : max_height;
        }
        else
        {
          base_icon_width = max_width > 0 ? max_width - RIBBON_PADDING * 2 : -1;
          base_icon_height = base_icon_width < 0 ? max_height - RIBBON_PADDING *2 : max_height;
        }
        helper_handle = impl->LoadFromGIconString(gicon_string.Str(),
                                                  base_icon_width,
                                                  base_icon_height,
                                                  helper_slot);

        return false;
      }
      else if (icon.IsType(G_TYPE_FILE_ICON))
      {
        // [trasfer none]
        GFile* file = ::g_file_icon_get_file(G_FILE_ICON(icon.RawPtr()));
        glib::String uri(::g_file_get_uri(file));

        type = REQUEST_TYPE_URI;
        data = uri.Str();

        return ProcessURITask();
      }
      else if (icon.IsType(G_TYPE_ICON))
      {
        GtkIconInfo *info = ::gtk_icon_theme_lookup_by_gicon(impl->theme_, icon, size,
                                                             GTK_ICON_LOOKUP_FORCE_SIZE);
        if (info)
        {
          icon_info = info;
          PushSchedulerJob();

          return false;
        }
        else
        {
          // There is some funkiness in some programs where they install
          // their icon to /usr/share/icons/hicolor/apps/, but they
          // name the Icon= key as `foo.$extension` which breaks loading
          // So we can try and work around that here.

          if (boost::iends_with(data, ".png") ||
              boost::iends_with(data, ".xpm") ||
              boost::iends_with(data, ".gif") ||
              boost::iends_with(data, ".jpg"))
          {
            data = data.substr(0, data.size() - 4);
            return ProcessIconNameTask();
          }
          else
          {
            LOG_WARNING(logger) << "Unable to load icon " << data
                                << " at size " << size;
          }
        }
      }
      else
      {
        LOG_WARNING(logger) << "Unable to load icon " << data
                            << " at size " << size << ": " << error;
      }

      InvokeSlot();
      return true;
    }

    bool ProcessURITask()
    {
      PushSchedulerJob();

      return false;
    }

    void CategoryIconLoaded(std::string const& base_icon_string,
                            int max_width, int max_height,
                            glib::Object<GdkPixbuf> const& category_pixbuf,
                            glib::Object<UnityProtocolAnnotatedIcon> const& anno_icon)
    {
      helper_handle = 0;
      bool has_emblem = category_pixbuf;

      const gchar* detail_text = unity_protocol_annotated_icon_get_ribbon(anno_icon);
      if (detail_text)
      {
        const int SHADOW_BOTTOM_PADDING = 2;
        const int SHADOW_SIDE_PADDING = 1;
        const int EMBLEM_PADDING = 2;
        int icon_w = gdk_pixbuf_get_width(result);
        int icon_h = gdk_pixbuf_get_height(result);

        int max_font_height;
        CalculateTextHeight(nullptr, &max_font_height);

        // FIXME: design wants the tags 2px wider than the original icon
        int pixbuf_width = icon_w;
        int pixbuf_height = max_font_height * 5 / 4 + SHADOW_BOTTOM_PADDING;
        if (pixbuf_height > icon_h) pixbuf_height = icon_h;

        nux::CairoGraphics cairo_graphics(CAIRO_FORMAT_ARGB32,
                                          pixbuf_width, pixbuf_height);
        cairo_t* cr = cairo_graphics.GetInternalContext();

        glib::Object<PangoLayout> layout;
        PangoContext* pango_context = NULL;
        GdkScreen* screen = gdk_screen_get_default(); // not ref'ed
        auto const& font = theme::Settings::Get()->font();

        cairo_set_font_options(cr, gdk_screen_get_font_options(screen));
        layout = pango_cairo_create_layout(cr);
        std::shared_ptr<PangoFontDescription> desc(pango_font_description_from_string(font.c_str()), pango_font_description_free);
        pango_font_description_set_weight(desc.get(), PANGO_WEIGHT_BOLD);
        int font_size = FONT_SIZE;
        pango_font_description_set_size (desc.get(), font_size * PANGO_SCALE);

        pango_layout_set_font_description(layout, desc.get());
        pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER);

        double belt_w = static_cast<double>(pixbuf_width - SHADOW_SIDE_PADDING * 2);
        double belt_h = static_cast<double>(pixbuf_height - SHADOW_BOTTOM_PADDING);

        double max_text_width = belt_w;
        if (has_emblem)
        {
          const double CURVE_MID_X = 0.4 * (belt_h / 20.0 * 24.0);
          const int category_pb_w = gdk_pixbuf_get_width(category_pixbuf);
          max_text_width = belt_w - CURVE_MID_X - category_pb_w - EMBLEM_PADDING;
        }

        pango_layout_set_wrap(layout, PANGO_WRAP_WORD_CHAR);
        pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_END);

        glib::String escaped_text(g_markup_escape_text(detail_text, -1));
        pango_layout_set_markup(layout, escaped_text, -1);

        pango_context = pango_layout_get_context(layout);  // is not ref'ed
        pango_cairo_context_set_font_options(pango_context, gdk_screen_get_font_options(screen));
        pango_cairo_context_set_resolution(pango_context, 96.0 * Settings::Instance().font_scaling());
        pango_layout_context_changed(layout);

        // find proper font size
        int text_width, text_height;
        pango_layout_get_pixel_size(layout, &text_width, nullptr);
        while (text_width > max_text_width && font_size > MIN_FONT_SIZE)
        {
          font_size--;
          pango_font_description_set_size (desc.get(), font_size * PANGO_SCALE);
          pango_layout_set_font_description(layout, desc.get());
          pango_layout_get_pixel_size(layout, &text_width, nullptr);
        }
        pango_layout_set_width(layout, static_cast<int>(max_text_width * PANGO_SCALE));

        cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
        cairo_paint(cr);

        cairo_set_operator(cr, CAIRO_OPERATOR_OVER);

        // this should be #dd4814
        const double ORANGE_R = 0.86666;
        const double ORANGE_G = 0.28235;
        const double ORANGE_B = 0.07843;

        // translate to make space for the shadow
        cairo_save(cr);
        cairo_translate(cr, 1.0, 1.0);

        cairo_set_source_rgba(cr, ORANGE_R, ORANGE_G, ORANGE_B, 1.0);

        // base ribbon
        cairo_rectangle(cr, 0.0, 0.0, belt_w, belt_h);
        cairo_fill_preserve(cr);

        // hightlight on left edge
        std::shared_ptr<cairo_pattern_t> pattern(
            cairo_pattern_create_linear(0.0, 0.0, belt_w, 0.0),
            cairo_pattern_destroy);
        cairo_pattern_add_color_stop_rgba(pattern.get(), 0.0, 1.0, 1.0, 1.0, 0.235294);
        cairo_pattern_add_color_stop_rgba(pattern.get(), 0.02, 1.0, 1.0, 1.0, 0.0);
        // and on right one
        if (!has_emblem)
        {
          cairo_pattern_add_color_stop_rgba(pattern.get(), 0.98, 1.0, 1.0, 1.0, 0.0);
          cairo_pattern_add_color_stop_rgba(pattern.get(), 1.0, 1.0, 1.0, 1.0, 0.235294);
        }
        cairo_pattern_add_color_stop_rgba(pattern.get(), 1.0, 1.0, 1.0, 1.0, 0.0);

        cairo_set_source(cr, pattern.get());
        cairo_fill(cr);

        if (has_emblem)
        {
          // size of the emblem
          const int category_pb_w = gdk_pixbuf_get_width(category_pixbuf);
          const int category_pb_h = gdk_pixbuf_get_height(category_pixbuf);

          // control and end points for the two bezier curves
          const double CURVE_X_MULT = belt_h / 20.0 * 24.0;
          const double CURVE_CP1_X = 0.25 * CURVE_X_MULT;
          const double CURVE_CP2_X = 0.2521 * CURVE_X_MULT;
          const double CURVE_CP3_X = 0.36875 * CURVE_X_MULT;
          const double CURVE_CP4_X = 0.57875 * CURVE_X_MULT;
          const double CURVE_CP5_X = 0.705417 * CURVE_X_MULT;
          const double CURVE_CP6_X = 0.723333 * CURVE_X_MULT;
          const double CURVE_CP7_X = 0.952375 * CURVE_X_MULT;

          const double CURVE_Y1 = 0.9825;
          const double CURVE_Y2 = 0.72725;
          const double CURVE_Y3 = 0.27275;

          const double CURVE_START_X = belt_w - category_pb_w - CURVE_CP5_X - EMBLEM_PADDING;
          //const double CURVE_END_X = CURVE_START_X + CURVE_X_MULT;

          cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 1.0);

          // paint the curved area
          cairo_move_to(cr, CURVE_START_X, belt_h);
          cairo_curve_to(cr, CURVE_START_X + CURVE_CP1_X, belt_h,
                                   CURVE_START_X + CURVE_CP2_X, CURVE_Y1 * belt_h,
                                   CURVE_START_X + CURVE_CP3_X, CURVE_Y2 * belt_h);
          cairo_line_to(cr, CURVE_START_X + CURVE_CP4_X, CURVE_Y3 * belt_h);
          cairo_curve_to(cr, CURVE_START_X + CURVE_CP5_X, 0.0,
                                   CURVE_START_X + CURVE_CP6_X, 0.0,
                                   CURVE_START_X + CURVE_CP7_X, 0.0);
          cairo_line_to(cr, belt_w, 0.0);
          cairo_line_to(cr, belt_w, belt_h);
          cairo_close_path(cr);
          cairo_fill(cr);

          // and the highlight
          pattern.reset(cairo_pattern_create_linear(CURVE_START_X, 0.0, belt_w, 0.0),
                        cairo_pattern_destroy);
          cairo_pattern_add_color_stop_rgba(pattern.get(), 0.0, 1.0, 1.0, 1.0, 0.0);
          cairo_pattern_add_color_stop_rgba(pattern.get(), 0.95, 1.0, 1.0, 1.0, 0.0);
          cairo_pattern_add_color_stop_rgba(pattern.get(), 1.0, 0.0, 0.0, 0.0, 0.235294);
          cairo_set_source(cr, pattern.get());
          cairo_rectangle(cr, CURVE_START_X, 0.0, belt_w - CURVE_START_X, belt_h);
          cairo_fill(cr);

          // paint the emblem
          double category_pb_x = belt_w - category_pb_w - EMBLEM_PADDING - 1;
          gdk_cairo_set_source_pixbuf(cr, category_pixbuf,
                                      category_pb_x, (belt_h - category_pb_h) / 2);
          cairo_paint(cr);
        }

        // paint the text
        cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 1.0);
        cairo_move_to(cr, 0.0, belt_h / 2);
        pango_layout_get_pixel_size(layout, nullptr, &text_height);
        // current point is now in the middle of the stripe, need to translate
        // it, so that the text is centered
        cairo_rel_move_to(cr, 0.0, text_height / -2.0);
        pango_cairo_show_layout(cr, layout);

        // paint the shadow
        cairo_restore(cr);

        pattern.reset(cairo_pattern_create_linear(0.0, belt_h, 0.0, belt_h + SHADOW_BOTTOM_PADDING),
                      cairo_pattern_destroy);
        cairo_pattern_add_color_stop_rgba(pattern.get(), 0.0, 0.0, 0.0, 0.0, 0.235294);
        cairo_pattern_add_color_stop_rgba(pattern.get(), 1.0, 0.0, 0.0, 0.0, 0.0);

        cairo_set_source(cr, pattern.get());

        cairo_rectangle(cr, 0.0, belt_h, belt_w, SHADOW_BOTTOM_PADDING);
        cairo_fill(cr);

        cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 0.1);
        cairo_rectangle(cr, 0.0, 1.0, 1.0, belt_h);
        cairo_fill(cr);

        cairo_rectangle(cr, belt_w, 1.0, 1.0, belt_h);
        cairo_fill(cr);

        // FIXME: going from image_surface to pixbuf, and then to texture :(
        glib::Object<GdkPixbuf> detail_pb(
            gdk_pixbuf_get_from_surface(cairo_graphics.GetSurface(),
                                        0, 0,
                                        cairo_graphics.GetWidth(),
                                        cairo_graphics.GetHeight()));

        int y_pos = icon_h - pixbuf_height - max_font_height / 2;
        gdk_pixbuf_composite(detail_pb, result, // src, dest
                             0, // dest_x
                             y_pos, // dest_y
                             pixbuf_width, // dest_w
                             pixbuf_height, // dest_h
                             0, // offset_x
                             y_pos, // offset_y
                             1.0, 1.0, // scale_x, scale_y
                             GDK_INTERP_NEAREST, // interpolation
                             255); // src_alpha
      }

      idles.AddIdle([this] { return LoadIconComplete(this) != FALSE; });
    }

    glib::Object<GdkPixbuf> ColorizeIcon(glib::Object<GdkPixbuf> const& pixbuf,
                                         double red, double green, double blue,
                                         double alpha)
    {
      int pixbuf_width = gdk_pixbuf_get_width(pixbuf);
      int pixbuf_height = gdk_pixbuf_get_height(pixbuf);

      nux::CairoGraphics cairo_graphics(CAIRO_FORMAT_ARGB32,
                                        pixbuf_width, pixbuf_height);
      cairo_t* cr = cairo_graphics.GetInternalContext();

      cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
      cairo_paint(cr);

      // paint the icon
      cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
      gdk_cairo_set_source_pixbuf(cr, pixbuf, 0.0, 0.0);
      cairo_paint(cr);

      // colorize it
      cairo_set_source_rgba(cr, red, green, blue, 1.0);
      // ATOP blends the original and source color, original alpha not affected
      cairo_set_operator(cr, CAIRO_OPERATOR_ATOP);
      cairo_paint(cr);

      if (alpha < 1.0)
      {
        cairo_set_operator(cr, CAIRO_OPERATOR_DEST_OUT);
        cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0 - alpha);
        cairo_paint(cr);
      }

      // copy the result surface into pixbuf
      glib::Object<GdkPixbuf> colorized_pixbuf(
          gdk_pixbuf_get_from_surface(cairo_graphics.GetSurface(),
                                      0, 0,
                                      cairo_graphics.GetWidth(),
                                      cairo_graphics.GetHeight()));

      return colorized_pixbuf;
    }

    void BaseIconLoaded(std::string const& base_icon_string,
                        int base_max_width, int base_max_height,
                        glib::Object<GdkPixbuf> const& base_icon,
                        glib::Object<UnityProtocolAnnotatedIcon> const& anno_icon)
    {
      helper_handle = 0;
      if (base_icon)
      {
        glib::Object<GdkPixbuf> base_pixbuf = base_icon;

        LOG_DEBUG(logger) << "Base icon loaded: '" << base_icon_string << 
          "' size: " << gdk_pixbuf_get_width(base_pixbuf) << 'x' <<
                        gdk_pixbuf_get_height(base_pixbuf);

        UnityProtocolCategoryType category = unity_protocol_annotated_icon_get_category(anno_icon);
        guint32 colorize_value = unity_protocol_annotated_icon_get_colorize_value(anno_icon);
        if (colorize_value != 0)
        {
          // extract rgba
          double alpha = (colorize_value & 0xFF) / 255.;
          colorize_value >>= 8;
          double blue = (colorize_value & 0xFF) / 255.;
          colorize_value >>= 8;
          double green = (colorize_value & 0xFF) / 255.;
          colorize_value >>= 8;
          double red = (colorize_value & 0xFF) / 255.;

          base_pixbuf = ColorizeIcon(base_pixbuf, red, green, blue, alpha);
        }

        // short-circuit if there's no text to overlay
        if (category == UNITY_PROTOCOL_CATEGORY_TYPE_NONE &&
            unity_protocol_annotated_icon_get_ribbon(anno_icon) == NULL)
        {
          // if the icon was requested to be smaller + colorized, we can cache
          no_cache = false;
          result = base_pixbuf;
          idles.AddIdle([this] { return LoadIconComplete(this) != FALSE; });
          return;
        }

        int result_width, result_height, dest_x, dest_y;
        if (unity_protocol_annotated_icon_get_use_small_icon(anno_icon))
        {
          result_width = max_width > 0 ? max_width : MAX(max_height, gdk_pixbuf_get_width(base_pixbuf));
          result_height = max_height > 0 ? max_height : MAX(max_width, gdk_pixbuf_get_height(base_pixbuf));

          dest_x = (result_width - gdk_pixbuf_get_width(base_pixbuf)) / 2;
          dest_y = (result_height - gdk_pixbuf_get_height(base_pixbuf)) / 2;
        }
        else
        {
          result_width = gdk_pixbuf_get_width(base_pixbuf) + RIBBON_PADDING * 2;
          result_height = gdk_pixbuf_get_height(base_pixbuf);

          dest_x = RIBBON_PADDING;
          dest_y = 0;
        }
        // we need extra space for the ribbon
        result = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8,
                                result_width, result_height);
        gdk_pixbuf_fill(result, 0x0);
        gdk_pixbuf_copy_area(base_pixbuf, 0, 0,
                             gdk_pixbuf_get_width(base_pixbuf),
                             gdk_pixbuf_get_height(base_pixbuf),
                             result,
                             dest_x, dest_y);
        // FIXME: can we composite the pixbuf in helper thread?
        auto helper_slot = sigc::bind(sigc::mem_fun(this, &IconLoaderTask::CategoryIconLoaded), anno_icon);
        int max_font_height;
        CalculateTextHeight(nullptr, &max_font_height);
        unsigned cat_size = max_font_height * 9 / 8;
        switch (category)
        {
          case UNITY_PROTOCOL_CATEGORY_TYPE_NONE:
            // rest of the processing is the CategoryIconLoaded, lets invoke it
            helper_slot("", -1, cat_size, glib::Object<GdkPixbuf>());
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_APPLICATION:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_apps", -1, cat_size, helper_slot);
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_BOOK:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_books", -1, cat_size, helper_slot);
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_MUSIC:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_music", -1, cat_size, helper_slot);
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_MOVIE:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_video", -1, cat_size, helper_slot);
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_CLOTHES:
          case UNITY_PROTOCOL_CATEGORY_TYPE_SHOES:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_clothes", -1, cat_size, helper_slot);
            break;
          case UNITY_PROTOCOL_CATEGORY_TYPE_GAMES:
          case UNITY_PROTOCOL_CATEGORY_TYPE_ELECTRONICS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_COMPUTERS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_OFFICE:
          case UNITY_PROTOCOL_CATEGORY_TYPE_HOME:
          case UNITY_PROTOCOL_CATEGORY_TYPE_GARDEN:
          case UNITY_PROTOCOL_CATEGORY_TYPE_PETS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_TOYS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_CHILDREN:
          case UNITY_PROTOCOL_CATEGORY_TYPE_BABY:
          case UNITY_PROTOCOL_CATEGORY_TYPE_WATCHES:
          case UNITY_PROTOCOL_CATEGORY_TYPE_SPORTS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_OUTDOORS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_GROCERY:
          case UNITY_PROTOCOL_CATEGORY_TYPE_HEALTH:
          case UNITY_PROTOCOL_CATEGORY_TYPE_BEAUTY:
          case UNITY_PROTOCOL_CATEGORY_TYPE_DIY:
          case UNITY_PROTOCOL_CATEGORY_TYPE_TOOLS:
          case UNITY_PROTOCOL_CATEGORY_TYPE_CAR:
          default:
            helper_handle =
              impl->LoadFromThemedFilename("emblem_others", -1, cat_size, helper_slot);
            break;
        }
      }
      else
      {
        result = nullptr;
        idles.AddIdle([this] { return LoadIconComplete(this) != FALSE; });
      }
    }

    void PushSchedulerJob()
    {
#if G_ENCODE_VERSION (GLIB_MAJOR_VERSION, GLIB_MINOR_VERSION) <= GLIB_VERSION_2_34
      g_io_scheduler_push_job (LoaderJobFunc, this, nullptr, G_PRIORITY_HIGH_IDLE, nullptr);
#else
      glib::Object<GTask> task(g_task_new(nullptr, nullptr, [] (GObject*, GAsyncResult*, gpointer data) {
        auto self = static_cast<IconLoaderTask*>(data);
        self->LoadIconComplete(data);
      }, this));

      g_task_set_priority(task, G_PRIORITY_HIGH_IDLE);
      g_task_set_task_data(task, this, nullptr);

      g_task_run_in_thread(task, LoaderJobFunc);
#endif
    }

    // Loading/rendering of pixbufs is done in a separate thread
#if G_ENCODE_VERSION (GLIB_MAJOR_VERSION, GLIB_MINOR_VERSION) <= GLIB_VERSION_2_34
    static gboolean LoaderJobFunc(GIOSchedulerJob* job, GCancellable *canc, gpointer data)
#else
    static void LoaderJobFunc(GTask* job, gpointer source_object, gpointer data, GCancellable* canc)
#endif
    {
      auto task = static_cast<IconLoaderTask*>(data);

      // careful here this is running in non-main thread
      if (task->icon_info)
      {
        task->result = ::gtk_icon_info_load_icon(task->icon_info, &task->error);
      }
      else if (task->type == REQUEST_TYPE_URI)
      {
        glib::Object<GFile> file(::g_file_new_for_uri(task->data.c_str()));
        glib::String contents;
        gsize length = 0;

        if (g_file_load_contents(file, canc, &contents, &length,
                                 nullptr, &task->error))
        {
          glib::Object<GInputStream> stream(
              g_memory_input_stream_new_from_data(contents.Value(), length, nullptr));

          task->result = gdk_pixbuf_new_from_stream_at_scale(stream,
                                                             task->max_width,
                                                             task->max_height,
                                                             TRUE,
                                                             canc,
                                                             &task->error);
          g_input_stream_close(stream, canc, nullptr);
        }
      }

#if G_ENCODE_VERSION (GLIB_MAJOR_VERSION, GLIB_MINOR_VERSION) <= GLIB_VERSION_2_34
      g_io_scheduler_job_send_to_mainloop_async (job, LoadIconComplete, task, nullptr);
      return FALSE;
#endif
    }

    // this will be invoked back in the thread from which push_job was called
    static gboolean LoadIconComplete(gpointer data)
    {
      auto task = static_cast<IconLoaderTask*>(data);
      auto impl = task->impl;

      if (task->result.IsType(GDK_TYPE_PIXBUF))
      {
        if (!task->no_cache) impl->cache_[task->key] = task->result;
      }
      else
      {
        if (task->result)
          task->result = nullptr;

        LOG_WARNING(logger) << "Unable to load icon " << task->data
                            << " at size "
                            << task->max_width << "x" << task->max_height
                            << ": " << task->error;
      }

      impl->finished_tasks_.push_back(task);

      if (!impl->coalesce_timeout_)
      {
        // we're using lower priority than the GIOSchedulerJob uses to deliver
        // results to the mainloop
        auto prio = static_cast<glib::Source::Priority>(glib::Source::Priority::DEFAULT_IDLE + 40);
        impl->coalesce_timeout_.reset(new glib::Timeout(40, prio));
        impl->coalesce_timeout_->Run(sigc::mem_fun(impl, &Impl::CoalesceTasksCb));
      }

      return FALSE;
    }
  };

  Handle ReturnCachedOrQueue(std::string const& data,
                             int max_width,
                             int max_height,
                             IconLoaderCallback const& slot,
                             IconLoaderRequestType type);

  Handle QueueTask(std::string const& key,
                   std::string const& data,
                   int max_width,
                   int max_height,
                   IconLoaderCallback const& slot,
                   IconLoaderRequestType type);

  std::string Hash(std::string const& data, int max_width, int max_height);

  bool CacheLookup(std::string const& key,
                   std::string const& data,
                   int max_width,
                   int max_height,
                   IconLoaderCallback const& slot);

  // Looping idle callback function
  bool Iteration();
  bool CoalesceTasksCb();

private:
  std::unordered_map<std::string, glib::Object<GdkPixbuf>> cache_;
  /* FIXME: the reference counting of IconLoaderTasks with shared pointers
   * is currently somewhat broken, and the queued_tasks_ member is what keeps
   * it from crashing randomly.
   * The IconLoader instance is assuming that it is the only owner of the loader
   * tasks, but when they are being completed in a worker thread, the thread
   * should own them as well (yet it doesn't), this could cause trouble
   * in the future... You've been warned! */
  std::unordered_map<std::string, IconLoaderTask::Ptr> queued_tasks_;
  std::queue<IconLoaderTask::Ptr> tasks_;
  std::unordered_map<Handle, IconLoaderTask::Ptr> task_map_;
  std::vector<IconLoaderTask*> finished_tasks_;

  bool no_load_;
  GtkIconTheme* theme_; // Not owned.
  Handle handle_counter_;
  glib::Source::UniquePtr idle_;
  glib::Source::UniquePtr coalesce_timeout_;
  connection::Wrapper theme_changed_;
};


IconLoader::Impl::Impl()
  : // Option to disable loading, if you're testing performance of other things
    no_load_(::getenv("UNITY_ICON_LOADER_DISABLE"))
  , theme_(::gtk_icon_theme_get_default())
  , handle_counter_(0)
{
  theme_changed_ = theme::Settings::Get()->icons_changed.connect([this] {
    /* Since the theme has been changed we can clear the cache, however we
     * could include two improvements here:
     *  1) clear only the themed icons in cache
     *  2) make the clients of this class to update their icons forcing them
     *     to reload the pixbufs and erase the cached textures, to make this
     *     apply immediately. */
    cache_.clear();
  });

  // make sure the AnnotatedIcon type is registered, so we can deserialize it
#if GLIB_CHECK_VERSION(2, 34, 0)
  g_type_ensure(unity_protocol_annotated_icon_get_type());
#else
  // we need to fool the compiler cause get_type is marked as G_GNUC_CONST,
  // which isn't exactly true
  volatile GType proto_icon = unity_protocol_annotated_icon_get_type();
  g_type_name(proto_icon);
#endif
}

IconLoader::Handle IconLoader::Impl::LoadFromIconName(std::string const& icon_name, int max_width, int max_height, IconLoaderCallback const& slot)
{
  if (no_load_ || icon_name.empty() || !slot ||
      ((max_width >= 0 && max_width < MIN_ICON_SIZE) ||
       (max_height >= 0 && max_height < MIN_ICON_SIZE)))
    return Handle();

  // We need to check this because of legacy desktop files
  if (icon_name[0] == '/')
  {
    return LoadFromFilename(icon_name, max_width, max_height, slot);
  }

  return ReturnCachedOrQueue(icon_name, max_width, max_height, slot,
                             REQUEST_TYPE_ICON_NAME);
}

IconLoader::Handle IconLoader::Impl::LoadFromGIconString(std::string const& gicon_string, int max_width, int max_height, IconLoaderCallback const& slot)
{
  if (no_load_ || gicon_string.empty() || !slot ||
      ((max_width >= 0 && max_width < MIN_ICON_SIZE) ||
       (max_height >= 0 && max_height < MIN_ICON_SIZE)))
    return Handle();

  return ReturnCachedOrQueue(gicon_string, max_width, max_height, slot,
                             REQUEST_TYPE_GICON_STRING);
}

IconLoader::Handle IconLoader::Impl::LoadFromFilename(std::string const& filename, int max_width, int max_height, IconLoaderCallback const& slot)
{
  if (no_load_ || filename.empty() || !slot ||
      ((max_width >= 0 && max_width < MIN_ICON_SIZE) ||
       (max_height >= 0 && max_height < MIN_ICON_SIZE)))
    return Handle();

  glib::Object<GFile> file(::g_file_new_for_path(filename.c_str()));
  glib::String uri(::g_file_get_uri(file));

  return LoadFromURI(uri.Str(), max_width, max_height, slot);
}

IconLoader::Handle IconLoader::Impl::LoadFromThemedFilename(std::string const& filename, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return LoadFromFilename(theme::Settings::Get()->ThemedFilePath(filename, {PKGDATADIR}), max_width, max_height, slot);
}

IconLoader::Handle IconLoader::Impl::LoadFromURI(std::string const& uri, int max_width, int max_height, IconLoaderCallback const& slot)
{
  if (no_load_ || uri.empty() || !slot ||
      ((max_width >= 0 && max_width < MIN_ICON_SIZE) ||
       (max_height >= 0 && max_height < MIN_ICON_SIZE)))
    return Handle();

  return ReturnCachedOrQueue(uri, max_width, max_height, slot,
                             REQUEST_TYPE_URI);
}

void IconLoader::Impl::DisconnectHandle(Handle handle)
{
  auto iter = task_map_.find(handle);

  if (iter != task_map_.end())
  {
    iter->second->slot = nullptr;
  }
}

void IconLoader::Impl::CalculateTextHeight(int* width, int* height)
{
  // FIXME: what about CJK?
  const char* const SAMPLE_MAX_TEXT = "Chromium Web Browser";

  nux::CairoGraphics util_cg(CAIRO_FORMAT_ARGB32, 1, 1);
  cairo_t* cr = util_cg.GetInternalContext();

  auto const& font = theme::Settings::Get()->font();
  std::shared_ptr<PangoFontDescription> desc(pango_font_description_from_string(font.c_str()), pango_font_description_free);
  pango_font_description_set_weight(desc.get(), PANGO_WEIGHT_BOLD);
  pango_font_description_set_size(desc.get(), FONT_SIZE * PANGO_SCALE);

  glib::Object<PangoLayout> layout(pango_cairo_create_layout(cr));
  pango_layout_set_font_description(layout, desc.get());
  pango_layout_set_text(layout, SAMPLE_MAX_TEXT, -1);

  PangoContext* cxt = pango_layout_get_context(layout);
  GdkScreen* screen = gdk_screen_get_default();
  pango_cairo_context_set_font_options(cxt, gdk_screen_get_font_options(screen));
  pango_cairo_context_set_resolution(cxt, 96.0 * Settings::Instance().font_scaling());
  pango_layout_context_changed(layout);

  PangoRectangle log_rect;
  pango_layout_get_extents(layout, NULL, &log_rect);

  if (width) *width = log_rect.width / PANGO_SCALE;
  if (height) *height = log_rect.height / PANGO_SCALE;
}

//
// Private Methods
//

IconLoader::Handle IconLoader::Impl::ReturnCachedOrQueue(std::string const& data, int max_width, int max_height, IconLoaderCallback const& slot, IconLoaderRequestType type)
{
  std::string key(Hash(data, max_width, max_height));

  if (!CacheLookup(key, data, max_width, max_height, slot))
  {
    return QueueTask(key, data, max_width, max_height, slot, type);
  }
  return Handle();
}


IconLoader::Handle IconLoader::Impl::QueueTask(std::string const& key, std::string const& data, int max_width, int max_height, IconLoaderCallback const& slot, IconLoaderRequestType type)
{
  auto task = std::make_shared<IconLoaderTask>(type, data,
                                               max_width, max_height,
                                               key, slot,
                                               ++handle_counter_, this);
  auto iter = queued_tasks_.find(key);

  if (iter != queued_tasks_.end())
  {
    IconLoaderTask::Ptr const& running_task = iter->second;
    running_task->shadow_tasks.push_back(task);
    // do NOT push the task into the tasks queue,
    // the parent task (which is in the queue) will handle it
    task_map_[task->handle] = task;

    LOG_DEBUG(logger) << "Appending shadow task  " << data
                      << ", queue size now at " << tasks_.size();

    return task->handle;
  }
  else
  {
    queued_tasks_[key] = task;
  }

  tasks_.push(task);
  task_map_[task->handle] = task;

  LOG_DEBUG(logger) << "Pushing task  " << data << " at size " 
                    << max_width << "x" << max_height
                    << ", queue size now at " << tasks_.size();

  if (!idle_)
  {
    idle_.reset(new glib::Idle(sigc::mem_fun(this, &Impl::Iteration), glib::Source::Priority::LOW));
  }
  return task->handle;
}

std::string IconLoader::Impl::Hash(std::string const& data, int max_width, int max_height)
{
  std::ostringstream sout;
  sout << data << ":" << max_width << "x" << max_height;
  return sout.str();
}

bool IconLoader::Impl::CacheLookup(std::string const& key,
                                   std::string const& data,
                                   int max_width,
                                   int max_height,
                                   IconLoaderCallback const& slot)
{
  auto iter = cache_.find(key);
  bool found = iter != cache_.end();

  if (found && slot)
  {
    glib::Object<GdkPixbuf> const& pixbuf = iter->second;
    slot(data, max_width, max_height, pixbuf);
  }

  return found;
}

bool IconLoader::Impl::CoalesceTasksCb()
{
  for (auto task : finished_tasks_)
  {
    task->InvokeSlot();

    // this was all async, we need to erase the task from the task_map
    task_map_.erase(task->handle);
    queued_tasks_.erase(task->key);
  }

  finished_tasks_.clear();
  coalesce_timeout_.reset();

  return false;
}

bool IconLoader::Impl::Iteration()
{
  static const int MAX_MICRO_SECS = 1000;
  util::Timer timer;

  bool queue_empty = tasks_.empty();

  // always do at least one iteration if the queue isn't empty
  while (!queue_empty)
  {
    IconLoaderTask::Ptr const& task = tasks_.front();

    if (task->Process())
    {
      task_map_.erase(task->handle);
      queued_tasks_.erase(task->key);
    }

    tasks_.pop();
    queue_empty = tasks_.empty();

    if (timer.ElapsedMicroSeconds() >= MAX_MICRO_SECS) break;
  }

  LOG_DEBUG(logger) << "Iteration done, queue size now at " << tasks_.size();

  if (queue_empty)
  {
    if (task_map_.empty())
      handle_counter_ = 0;

    idle_.reset();
  }

  return !queue_empty;
}

IconLoader::IconLoader()
  : pimpl(new Impl())
{
}

IconLoader::~IconLoader()
{
}

IconLoader& IconLoader::GetDefault()
{
  static IconLoader default_loader;
  return default_loader;
}

IconLoader::Handle IconLoader::LoadFromIconName(std::string const& icon_name, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return pimpl->LoadFromIconName(icon_name, max_width, max_height, slot);
}

IconLoader::Handle IconLoader::LoadFromGIconString(std::string const& gicon_string, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return pimpl->LoadFromGIconString(gicon_string, max_width, max_height, slot);
}

IconLoader::Handle IconLoader::LoadFromFilename(std::string const& filename, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return pimpl->LoadFromFilename(filename, max_width, max_height, slot);
}

IconLoader::Handle IconLoader::LoadFromThemedFilename(std::string const& filename, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return pimpl->LoadFromThemedFilename(filename, max_width, max_height, slot);
}

IconLoader::Handle IconLoader::LoadFromURI(std::string const& uri, int max_width, int max_height, IconLoaderCallback const& slot)
{
  return pimpl->LoadFromURI(uri, max_width, max_height, slot);
}

void IconLoader::DisconnectHandle(Handle handle)
{
  pimpl->DisconnectHandle(handle);
}


}
