show guild icon previews as grid in folder button

src/components/channellist/classic/guildlist.cpp

@@ -64,7 +64,7 @@ void GuildList::AddFolder(const UserSettingsGuildFoldersEntry &folder) {
         return;
     }
 
-    auto *folder_widget = Gtk::make_managed<GuildListFolderItem>();
+    auto *folder_widget = Gtk::make_managed<GuildListFolderItem>(folder);
     for (const auto guild_id : folder.GuildIDs) {
         if (auto *guild_widget = CreateGuildWidget(guild_id)) {
             guild_widget->show();

src/components/channellist/classic/guildlistfolderitem.cpp

@@ -1,7 +1,46 @@
 #include "guildlistfolderitem.hpp"
 #include "guildlistguilditem.hpp"
 
-GuildListFolderItem::GuildListFolderItem() {
+// doing my best to copy discord here
+
+const int FolderGridButtonSize = 48;
+const int FolderGridImageSize = 24;
+
+class GuildListFolderButton : public Gtk::Grid {
+public:
+    GuildListFolderButton() {
+        set_size_request(FolderGridButtonSize, FolderGridButtonSize);
+    }
+
+    void SetGuilds(const std::vector<Snowflake> &guild_ids) {
+        for (int y = 0; y < 2; y++) {
+            for (int x = 0; x < 2; x++) {
+                const size_t i = y * 2 + x;
+                auto &widget = m_images[x][y];
+                widget.property_pixbuf() = Abaddon::Get().GetImageManager().GetPlaceholder(FolderGridImageSize);
+                attach(widget, x, y, 1, 1);
+
+                if (i < guild_ids.size()) {
+                    widget.show();
+
+                    if (const auto guild = Abaddon::Get().GetDiscordClient().GetGuild(guild_ids[i]); guild.has_value()) {
+                        const auto cb = [&widget](const Glib::RefPtr<Gdk::Pixbuf> &pb) {
+                            widget.property_pixbuf() = pb->scale_simple(FolderGridImageSize, FolderGridImageSize, Gdk::INTERP_BILINEAR);
+                        };
+                        Abaddon::Get().GetImageManager().LoadFromURL(guild->GetIconURL("png", "32"), sigc::track_obj(cb, *this));
+                    }
+                }
+            }
+        }
+    }
+
+private:
+    Gtk::Image m_images[2][2];
+};
+
+GuildListFolderItem::GuildListFolderItem(const UserSettingsGuildFoldersEntry &folder) {
+    get_style_context()->add_class("classic-guild-folder");
+
     m_revealer.add(m_box);
     m_revealer.set_reveal_child(true);
 
@@ -14,10 +53,18 @@ GuildListFolderItem::GuildListFolderItem() {
         return false;
     });
 
-    m_ev.add(m_image);
+    auto *btn = Gtk::make_managed<GuildListFolderButton>();
+    btn->SetGuilds(folder.GuildIDs);
+    m_ev.add(*btn);
     add(m_ev);
     add(m_revealer);
-    show_all_children();
+
+    btn->show();
+    m_ev.show();
+    m_revealer.show();
+    m_box.show();
+    m_image.show();
+    show();
 }
 
 void GuildListFolderItem::AddGuildWidget(GuildListGuildItem *widget) {

src/components/channellist/classic/guildlistfolderitem.hpp

@@ -5,12 +5,13 @@
 #include <gtkmm/revealer.h>
 
 #include "guildlistguilditem.hpp"
+#include "discord/usersettings.hpp"
 
 class GuildListGuildItem;
 
 class GuildListFolderItem : public Gtk::VBox {
 public:
-    GuildListFolderItem();
+    GuildListFolderItem(const UserSettingsGuildFoldersEntry &folder);
 
     void AddGuildWidget(GuildListGuildItem *widget);