Add GTK application implementation

data/data.go

@@ -0,0 +1,32 @@
+package data
+
+import (
+	_ "embed"
+)
+
+//go:embed ui/window.ui
+var WindowXML string
+
+//go:embed ui/shortcuts-dialog.ui
+var ShortcutsDialogXML string
+
+//go:embed ui/connection-panel.ui
+var ConnectionPanelXML string
+
+//go:embed ui/server-panel.ui
+var ServerPanelXML string
+
+//go:embed ui/cover-panel.ui
+var CoverPanelXML string
+
+//go:embed ui/playlist-panel.ui
+var PlaylistPanelXML string
+
+//go:embed ui/album-headerbar.ui
+var AlbumHeaderbarXML string
+
+//go:embed ui/library-panel.ui
+var LibraryPanelXML string
+
+//go:embed gtk.css
+var MainCSS string

data/gtk.css

@@ -1,6 +1,5 @@
 #content_stack {
     box-shadow:inset 4px 4px 10px rgba(0,0,0,0.3);
-    background-image:url('noise-texture.png');
 }
 
 #port_spinner {
@@ -30,10 +29,6 @@
     font-weight:bold;
 }
 
-window.fullscreen #cover_box {
-    background: black;
-}
-
 #cover_info_revealer {
     background-color:alpha(@theme_bg_color, 0.8);
     box-shadow:0 0 10px @theme_bg_color;

data/icons/meson.build

@@ -1,7 +0,0 @@
-application_id = 'xyz.suruatoel.mcg'
-
-scalable_dir = join_paths('hicolor', 'scalable', 'apps')
-install_data(
-    join_paths(scalable_dir, ('@0@.svg').format(application_id)),
-    install_dir: join_paths(get_option('datadir'), 'icons', scalable_dir)
-)

data/ui/album-headerbar.ui

@@ -2,7 +2,7 @@
 <interface>
   <requires lib="gtk+" version="4.8"/>
   <requires lib="adw" version="1.2" />
-  <template class="McgAlbumHeaderbar" parent="AdwBin">
+  <object id="McgAlbumHeaderbar" class="AdwBin">
     <child>
       <object class="GtkHeaderBar">
         <child type="title">
@@ -25,9 +25,8 @@
           </object>
         </child>
         <child>
-          <object class="GtkButton">
+          <object id="close_button" class="GtkButton">
             <property name="receives-default">True</property>
-            <signal name="clicked" handler="on_close_clicked" swapped="no"/>
             <child>
               <object class="GtkImage">
                 <property name="icon-name">go-previous-symbolic</property>
@@ -37,5 +36,5 @@
         </child>
       </object>
     </child>
-  </template>
+  </object>
 </interface>

data/ui/connection-panel.ui

@@ -9,31 +9,14 @@
     <property name="step-increment">1</property>
     <property name="page-increment">100</property>
   </object>
-  <object class="GtkBox" id="toolbar">
+  <object id="McgConnectionPanel" class="AdwBin">
-    <property name="orientation">horizontal</property>
-    <property name="spacing">6</property>
-  </object>
-  <template class="McgConnectionPanel" parent="AdwBin">
     <child>
       <object class="AdwStatusPage">
         <property name="title">Connect to MPD</property>
         <child>
-          <object class="GtkBox">
+          <object class="GtkListBox">
             <property name="hexpand">false</property>
             <property name="halign">center</property>
-            <child>
-              <object class="GtkListBox" id="zeroconf_list">
-                <property name="hexpand">true</property>
-                <child type="placeholder">
-                  <object class="GtkLabel">
-                    <property name="label" translatable="yes">No service found</property>
-                  </object>
-                </child>
-              </object>
-            </child>
-            <child>
-              <object class="GtkListBox">
-                <property name="hexpand">true</property>
             <property name="selection-mode">none</property>
             <style>
               <class name="boxed-list"/>
@@ -42,7 +25,6 @@
               <object class="AdwEntryRow" id="host_row">
                 <property name="title" translatable="yes">Host</property>
                 <property name="show-apply-button">true</property>
-                    <signal name="apply" handler="on_host_entry_apply"/>
               </object>
             </child>
             <child>
@@ -66,7 +48,6 @@
                     <property name="name">port_spinner</property>
                     <property name="value">6600</property>
                     <property name="adjustment">server-port-adjustment</property>
-                        <signal name="value-changed" handler="on_port_spinner_value_changed"/>
                   </object>
                 </child>
               </object>
@@ -82,6 +63,4 @@
       </object>
     </child>
   </object>
-    </child>
-  </template>
 </interface>

data/ui/cover-panel.ui

@@ -19,7 +19,7 @@
       </object>
     </child>
   </object>
-  <template class="McgCoverPanel" parent="GtkOverlay">
+  <object id="McgCoverPanel" class="GtkOverlay">
     <child>
       <object class="GtkStack" id="cover_stack">
         <property name="visible-child">cover_default</property>
@@ -157,5 +157,5 @@
         </child>
       </object>
     </child>
-  </template>
+  </object>
 </interface>

data/ui/library-panel.ui

@@ -26,13 +26,11 @@
             <property name="round-digits">0</property>
             <property name="digits">0</property>
             <property name="has-origin">False</property>
-            <signal name="value-changed" handler="on_grid_scale_changed" swapped="no"/>
           </object>
         </child>
         <child>
           <object class="GtkButton" id="library-toolbar-update">
             <property name="label" translatable="yes">update library</property>
-            <signal name="clicked" handler="on_update_clicked" swapped="no"/>
           </object>
         </child>
         <child>
@@ -53,7 +51,6 @@
                 <property name="label" translatable="yes">sort by artist</property>
                 <property name="receives-default">False</property>
                 <property name="group">sort_year</property>
-                <signal name="toggled" handler="on_sort_toggled" swapped="no"/>
               </object>
             </child>
             <child>
@@ -61,14 +58,12 @@
                 <property name="label" translatable="yes">sort by title</property>
                 <property name="receives-default">False</property>
                 <property name="group">sort_year</property>
-                <signal name="toggled" handler="on_sort_toggled" swapped="no"/>
               </object>
             </child>
             <child>
               <object class="GtkCheckButton" id="sort_year">
                 <property name="label" translatable="yes">sort by year</property>
                 <property name="receives-default">False</property>
-                <signal name="toggled" handler="on_sort_toggled" swapped="no"/>
               </object>
             </child>
             <child>
@@ -76,7 +71,6 @@
                 <property name="label" translatable="yes">sort by modification</property>
                 <property name="receives-default">False</property>
                 <property name="group">sort_year</property>
-                <signal name="toggled" handler="on_sort_toggled" swapped="no"/>
               </object>
             </child>
             <child>
@@ -86,7 +80,6 @@
                 <property name="can-focus">True</property>
                 <property name="receives-default">False</property>
                 <property name="active">True</property>
-                <signal name="toggled" handler="on_sort_order_toggled" swapped="no"/>
               </object>
             </child>
           </object>
@@ -108,9 +101,6 @@
             <property name="icon-name">system-search-symbolic</property>
           </object>
         </child>
-        <!--
-        <accelerator key="f" signal="activate" modifiers="GDK_CONTROL_MASK"/>
-        -->
       </object>
     </child>
     <child>
@@ -119,7 +109,6 @@
         <property name="can-focus">True</property>
         <property name="receives-default">True</property>
         <property name="tooltip-text" translatable="yes">Select multiple albums</property>
-        <signal name="toggled" handler="on_select_toggled" swapped="no"/>
         <child>
           <object class="GtkImage">
             <property name="icon-name">object-select-symbolic</property>
@@ -145,7 +134,7 @@
     </child>
   </object>
 
-  <template class="McgLibraryPanel" parent="AdwBin">
+  <object id="McgLibraryPanel" class="AdwBin">
     <child>
       <object class="GtkStack" id="library_stack">
         <property name="transition-type">slide-left-right</property>
@@ -158,7 +147,6 @@
                 <child>
                   <object class="GtkSearchEntry" id="filter_entry">
                     <property name="placeholder-text" translatable="yes">search library</property>
-                    <signal name="search-changed" handler="on_filter_entry_changed" swapped="no"/>
                   </object>
                 </child>
               </object>
@@ -206,49 +194,9 @@
                     <object class="GtkGridView" id="library_grid">
                       <property name="orientation">vertical</property>
                       <property name="single_click_activate">true</property>
-                      <signal name="activate" handler="on_library_grid_clicked"/>
                       <style>
                         <class name="no-bg"/>
                       </style>
-                      <property name="factory">
-                        <object class="GtkBuilderListItemFactory">
-                          <property name="bytes">
-<![CDATA[
-<?xml version="1.0" encoding="UTF-8"?>
-  <interface>
-    <template class="GtkListItem">
-      <property name="activatable">true</property>
-      <property name="child">
-        <object class="GtkBox">
-          <property name="orientation">vertical</property>
-          <property name="vexpand">true</property>
-          <property name="hexpand">true</property>
-          <child>
-            <object class="GtkPicture">
-              <property name="content-fit">contain</property>
-              <property name="can-shrink">false</property>
-              <property name="vexpand">true</property>
-              <property name="hexpand">true</property>
-              <binding name="tooltip-markup">
-                <lookup name="tooltip" type="GridItem">
-                  <lookup name="item">GtkListItem</lookup>
-                </lookup>
-              </binding>
-              <binding name="paintable">
-                <lookup name="cover" type="GridItem">
-                  <lookup name="item">GtkListItem</lookup>
-                </lookup>
-              </binding>
-            </object>
-          </child>
-        </object>
-      </property>
-    </template>
-  </interface>
-]]>
-                          </property>
-                        </object>
-                      </property>
                     </object>
                   </child>
                   <style>
@@ -264,17 +212,15 @@
               <child>
                 <object class="GtkActionBar" id="actionbar">
                   <child type="end">
-                    <object class="GtkButton">
+                    <object class="GtkButton" id="selection_cancel_button">
                       <property name="label" translatable="yes">cancel</property>
                       <property name="receives-default">True</property>
-                      <signal name="clicked" handler="on_selection_cancel_clicked" swapped="no"/>
                     </object>
                   </child>
                   <child type="end">
-                    <object class="GtkButton">
+                    <object class="GtkButton" id="selection_queue_button">
                       <property name="label" translatable="yes">queue</property>
                       <property name="receives-default">True</property>
-                      <signal name="clicked" handler="on_selection_add_clicked" swapped="no"/>
                     </object>
                   </child>
                 </object>
@@ -321,17 +267,15 @@
           <child>
             <object class="GtkActionBar" id="actionbar_standalone">
               <child type="end">
-                <object class="GtkButton">
+                <object class="GtkButton" id="standalone_play_button">
                   <property name="label" translatable="yes">play</property>
                   <property name="receives-default">True</property>
-                  <signal name="clicked" handler="on_standalone_play_clicked" swapped="no"/>
                 </object>
               </child>
               <child type="end">
-                <object class="GtkButton">
+                <object class="GtkButton" id="standalone_queue_button">
                   <property name="label" translatable="yes">queue</property>
                   <property name="receives-default">True</property>
-                  <signal name="clicked" handler="on_standalone_queue_clicked" swapped="no"/>
                 </object>
               </child>
             </object>
@@ -340,5 +284,5 @@
         </child>
       </object>
     </child>
-  </template>
+  </object>
 </interface>

data/ui/playlist-panel.ui

@@ -12,7 +12,6 @@
         <property name="can-focus">True</property>
         <property name="receives-default">True</property>
         <property name="tooltip-text" translatable="yes">Select multiple albums</property>
-        <signal name="toggled" handler="on_select_toggled" swapped="no"/>
         <child>
           <object class="GtkImage">
             <property name="icon-name">object-select-symbolic</property>
@@ -26,7 +25,6 @@
         <property name="can-focus">True</property>
         <property name="receives-default">True</property>
         <property name="tooltip-text" translatable="yes">Clear the playlist</property>
-        <signal name="clicked" handler="on_clear_clicked" swapped="no"/>
         <child>
           <object class="GtkImage">
             <property name="visible">True</property>
@@ -37,7 +35,7 @@
       </object>
     </child>
   </object>
-  <template class="McgPlaylistPanel" parent="AdwBin">
+  <object id="McgPlaylistPanel" class="AdwBin">
     <child>
       <object class="GtkStack" id="playlist_stack">
         <property name="transition-type">slide-left-right</property>
@@ -51,45 +49,9 @@
                   <object class="GtkGridView" id="playlist_grid">
                     <property name="orientation">vertical</property>
                     <property name="single-click-activate">true</property>
-                    <signal name="activate" handler="on_playlist_grid_clicked"/>
                     <style>
                       <class name="no-bg"/>
                     </style>
-                    <property name="factory">
-                      <object class="GtkBuilderListItemFactory">
-                        <property name="bytes">
-<![CDATA[
-<?xml version="1.0" encoding="UTF-8"?>
-  <interface>
-    <template class="GtkListItem">
-      <property name="activatable">true</property>
-      <property name="child">
-        <object class="GtkBox">
-          <property name="orientation">vertical</property>
-          <child>
-            <object class="GtkPicture">
-              <property name="content-fit">contain</property>
-              <property name="can-shrink">false</property>
-              <binding name="tooltip-markup">
-                <lookup name="tooltip" type="GridItem">
-                  <lookup name="item">GtkListItem</lookup>
-                </lookup>
-              </binding>
-              <binding name="paintable">
-                <lookup name="cover" type="GridItem">
-                  <lookup name="item">GtkListItem</lookup>
-                </lookup>
-              </binding>
-            </object>
-          </child>
-        </object>
-      </property>
-    </template>
-  </interface>
-]]>
-                        </property>
-                      </object>
-                    </property>
                   </object>
                 </child>
                 <style>
@@ -103,17 +65,15 @@
                 <child>
                   <object class="GtkActionBar" id="actionbar">
                     <child type="end">
-                      <object class="GtkButton">
+                      <object class="GtkButton" id="selection_cancel_button">
                         <property name="label" translatable="yes">cancel</property>
                         <property name="receives-default">True</property>
-                        <signal name="clicked" handler="on_selection_cancel_clicked" swapped="no"/>
                       </object>
                     </child>
                     <child type="end">
-                      <object class="GtkButton">
+                      <object class="GtkButton" id="selection_remove_button">
                         <property name="label" translatable="yes">remove</property>
                         <property name="receives-default">True</property>
-                        <signal name="clicked" handler="on_selection_remove_clicked" swapped="no"/>
                       </object>
                     </child>
                   </object>
@@ -159,17 +119,15 @@
             <child>
               <object class="GtkActionBar" id="actionbar_standalone">
                 <child type="end">
-                  <object class="GtkButton">
+                  <object class="GtkButton" id="standalone_play_button">
                     <property name="label" translatable="yes">play</property>
                     <property name="receives-default">True</property>
-                    <signal name="clicked" handler="on_standalone_play_clicked" swapped="no"/>
                   </object>
                 </child>
                 <child type="end">
-                  <object class="GtkButton">
+                  <object class="GtkButton" id="standalone_remove_button">
                     <property name="label" translatable="yes">remove</property>
                     <property name="receives-default">True</property>
-                    <signal name="clicked" handler="on_standalone_remove_clicked" swapped="no"/>
                   </object>
                 </child>
               </object>
@@ -178,5 +136,5 @@
         </child>
       </object>
     </child>
-  </template>
+  </object>
 </interface>

data/ui/server-panel.ui

@@ -13,7 +13,7 @@
       </object>
     </child>
   </object>
-  <template class="McgServerPanel" parent="AdwBin">
+  <object id="McgServerPanel" class="AdwBin">
     <child>
       <object class="AdwFlap" id="server_flap">
         <property name="flap-position">end</property>
@@ -322,5 +322,5 @@
         </property>
       </object>
     </child>
-  </template>
+  </object>
 </interface>

data/ui/shortcuts-dialog.ui

@@ -2,7 +2,7 @@
 <interface>
   <requires lib="gtk+" version="4.8"/>
   <requires lib="adw" version="1.2" />
-  <template class="McgShortcutsDialog" parent="GtkShortcutsWindow">
+  <object id="McgShortcutsDialog" class="GtkShortcutsWindow">
     <property name="modal">1</property>
     <child>
       <object class="GtkShortcutsSection">
@@ -103,5 +103,5 @@
         </child>
       </object>
     </child>
-</template>
+  </object>
 </interface>

data/ui/window.ui

@@ -2,7 +2,8 @@
 <interface>
   <requires lib="gtk+" version="4.8" />
   <requires lib="adw" version="1.2" />
-  <template class="McgAppWindow" parent="AdwApplicationWindow">
+  <object id="McgAppWindow" class="AdwApplicationWindow">
+    <property name="title">CoverGrid</property>
     <property name="content">
       <object class="AdwToolbarView" id="toolbar_view">
         <child type="top">
@@ -17,13 +18,12 @@
             </property>
             <child>
               <object class="GtkSwitch" id="headerbar_button_connect">
-                <signal name="state-set" handler="on_headerbar_connection_state_set" swapped="no"/>
               </object>
             </child>
             <child>
               <object class="GtkToggleButton" id="headerbar_button_playpause">
+                <property name="sensitive">false</property>
                 <property name="tooltip-text" translatable="yes">Switch between play and pause</property>
-                <signal name="toggled" handler="on_headerbar_playpause_toggled" swapped="no"/>
                 <child>
                   <object class="GtkImage">
                     <property name="can-focus">False</property>
@@ -34,7 +34,7 @@
             </child>
             <child>
               <object class="GtkVolumeButton" id="headerbar_button_volume">
-                <signal name="value-changed" handler="on_headerbar_volume_changed" swapped="no"/>
+                <property name="sensitive">false</property>
               </object>
             </child>
             <child type="end">
@@ -44,7 +44,7 @@
           </object>
         </child>
         <property name="content">
-          <object class="GtkBox" id="content_box">
+          <object class="GtkBox">
             <property name="orientation">vertical</property>
             <child>
               <object class="AdwToastOverlay" id="info_toast">
@@ -55,7 +55,6 @@
                     <child>
                       <object class="AdwViewStack" id="panel_stack">
                         <property name="vexpand">true</property>
-                        <signal name="notify::visible-child" handler="on_stack_switched" swapped="no"/>
                       </object>
                     </child>
                   </object>
@@ -70,9 +69,13 @@
                 </binding>
               </object>
             </child>
+            <child>
+              <object class="GtkDrawingArea" id="resize_helper">
+              </object>
+            </child>
           </object>
         </property>
       </object>
     </property>
-  </template>
+  </object>
 </interface>

data/xyz.suruatoel.mcg.gresource.xml

@@ -1,15 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<gresources>
-    <gresource prefix="/xyz/suruatoel/mcg">
-        <file>gtk.css</file>
-        <file>noise-texture.png</file>
-        <file>ui/window.ui</file>
-        <file>ui/shortcuts-dialog.ui</file>
-        <file>ui/connection-panel.ui</file>
-        <file>ui/album-headerbar.ui</file>
-        <file>ui/server-panel.ui</file>
-        <file>ui/cover-panel.ui</file>
-        <file>ui/playlist-panel.ui</file>
-        <file>ui/library-panel.ui</file>
-    </gresource>
-</gresources>

data/xyz.suruatoel.mcg.gschema.xml

@@ -1,63 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<schemalist>
-    <enum id="xyz.suruatoel.mcg.SortOrder">
-        <value nick="artist" value="0" />
-        <value nick="title" value="1" />
-        <value nick="year" value="2" />
-        <value nick="modified" value="3" />
-    </enum>
-	<schema path="/xyz/suruatoel/mcg/" id="xyz.suruatoel.mcg" gettext-domain="mcg">
-		<key type="s" name="host">
-			<default>'localhost'</default>
-			<summary>MPD host</summary>
-			<description>MPD host to connect to</description>
-		</key>
-		<key type="i" name="port">
-			<default>6600</default>
-			<summary>MPD port</summary>
-			<description>MPD port to connect to</description>
-		</key>
-		<key type="b" name="connected">
-			<default>false</default>
-			<summary>Connection state</summary>
-			<description>State of last connection</description>
-		</key>
-		<key type="i" name="width">
-			<default>800</default>
-			<summary>Window width</summary>
-			<description>The window width in pixels.</description>
-		</key>
-		<key type="i" name="height">
-			<default>600</default>
-			<summary>Window height</summary>
-			<description>The window height in pixels.</description>
-		</key>
-		<key type="b" name="is-maximized">
-			<default>false</default>
-			<summary>Window maximized</summary>
-			<description>Whether or not the window is in maximized state.</description>
-		</key>
-		<key type="i" name="panel">
-			<range min="0" max="3"/>
-			<default>1</default>
-			<summary>Last selected panel</summary>
-			<description>The index of the last selected panel.</description>
-		</key>
-		<key type="i" name="item-size">
-			<range min="100" max="1000" />
-			<default>150</default>
-			<summary>Size of library items</summary>
-			<description>The size of items displayed in the library.</description>
-		</key>
-		<key enum="xyz.suruatoel.mcg.SortOrder" name="sort-order">
-			<default>'year'</default>
-			<summary>Sort criterium for library items</summary>
-			<description>The sort criterium of items displayed in the library.</description>
-		</key>
-		<key type="b" name="sort-type">
-			<default>true</default>
-			<summary>Sort type for library items</summary>
-			<description>The sort type of items displayed in the library.</description>
-		</key>
-	</schema>
-</schemalist>

go.mod

@@ -3,3 +3,10 @@ module suruatoel.xyz/mcg
 go 1.25.0
 
 toolchain go1.26.0
+
+require (
+	github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20260808200908-d4aecaa0ff32
+	github.com/diamondburned/gotk4/pkg v0.4.1
+)
+
+require golang.org/x/sync v0.22.0 // indirect

go.sum

@@ -0,0 +1,6 @@
+github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20260808200908-d4aecaa0ff32 h1:1EATAO7ZRrY7B7lt6djCzGnLPlKXPzuOuwPzDSF7jT0=
+github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20260808200908-d4aecaa0ff32/go.mod h1:ZzYiyPe0TqsukfPHi0sK/WwKzm0wIJdSRylLnuvAZNw=
+github.com/diamondburned/gotk4/pkg v0.4.1 h1:w4BwVUUBkKyNLz5HKHN2Oz3kZCTLHfpfKgB/su1p6uo=
+github.com/diamondburned/gotk4/pkg v0.4.1/go.mod h1:BAEEDXtj5srQ1S2++5HX2K1s9c6CtuWSa60dAywrkRM=
+golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
+golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=

internal/gui/albumheaderbar.go

@@ -0,0 +1,42 @@
+package gui
+
+import (
+	"strings"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type albumHeaderbar struct {
+	*adw.Bin
+	titleLabel  *gtk.Label
+	artistLabel *gtk.Label
+	closeButton *gtk.Button
+}
+
+func newAlbumHeaderbar() *albumHeaderbar {
+	bar := albumHeaderbar{}
+	bar.loadWidgets()
+
+	return &bar
+}
+
+func (b *albumHeaderbar) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.AlbumHeaderbarXML)
+
+	b.Bin = builder.GetObject("McgAlbumHeaderbar").Cast().(*adw.Bin)
+	b.titleLabel = builder.GetObject("standalone_title").Cast().(*gtk.Label)
+	b.artistLabel = builder.GetObject("standalone_artist").Cast().(*gtk.Label)
+	b.closeButton = builder.GetObject("close_button").Cast().(*gtk.Button)
+}
+
+func (b *albumHeaderbar) SetAlbum(album *common.Album) {
+	b.titleLabel.SetText(album.Title())
+	b.artistLabel.SetText(strings.Join(album.Artists(), ", "))
+}
+
+func (b *albumHeaderbar) ConnectClose(callback func()) {
+	b.closeButton.ConnectClicked(callback)
+}

internal/gui/application.go

@@ -0,0 +1,151 @@
+package gui
+
+import (
+	"log"
+	"os"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gio/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/i18n"
+)
+
+type Application struct {
+	*gtk.Application
+	window      *mainWindow
+	aboutDialog *adw.AboutDialog
+	config      Configuration
+	configErr   error
+}
+
+func NewApplication() *Application {
+	app := Application{
+		Application: gtk.NewApplication("xyz.suruatoel.mcg", gio.ApplicationFlagsNone),
+	}
+	app.ConnectStartup(app.onStartup)
+	app.ConnectActivate(app.onActivate)
+	app.ConnectShutdown(app.onShutdown)
+
+	return &app
+}
+
+func (a *Application) onStartup() {
+	a.setDefaultSettings()
+	a.loadCSS()
+	a.registerShortcuts()
+	a.registerActions()
+	a.loadConfig()
+}
+
+func (a *Application) loadConfig() {
+	a.config = Configuration{
+		Host:      "localhost",
+		Port:      6600,
+		Panel:     "library",
+		SortField: "year",
+		SortDesc:  false,
+	}
+
+	a.configErr = readConfig(&a.config)
+}
+
+func (a *Application) setDefaultSettings() {
+	styleManager := adw.StyleManagerGetDefault()
+	styleManager.SetColorScheme(adw.ColorSchemePreferDark)
+}
+
+func (a *Application) loadCSS() {
+	styleProvider := gtk.NewCSSProvider()
+	styleProvider.LoadFromString(data.MainCSS)
+
+	gtk.StyleContextAddProviderForDisplay(
+		gdk.DisplayGetDefault(),
+		styleProvider,
+		gtk.STYLE_PROVIDER_PRIORITY_APPLICATION,
+	)
+}
+
+func (a *Application) registerShortcuts() {
+	a.SetAccelsForAction("window.close", []string{"<primary>q"})
+	a.SetAccelsForAction("win.show-help-overlay", []string{"<primary>k"})
+	a.SetAccelsForAction("app.info", []string{"<primary>i"})
+	a.SetAccelsForAction("win.connect", []string{"<primary>c"})
+	a.SetAccelsForAction("win.play", []string{"<primary>p"})
+	a.SetAccelsForAction("win.clear-playlist", []string{"<primary>r"})
+	a.SetAccelsForAction("win.toggle-fullscreen", []string{"F11"})
+	a.SetAccelsForAction("win.search-library", []string{"<primary>f"})
+	a.SetAccelsForAction("win.panel(\"server\")", []string{"<primary>KP_1"})
+	a.SetAccelsForAction("win.panel(\"cover\")", []string{"<primary>KP_2"})
+	a.SetAccelsForAction("win.panel(\"playlist\")", []string{"<primary>KP_3"})
+	a.SetAccelsForAction("win.panel(\"library\")", []string{"<primary>KP_4"})
+}
+
+func (a *Application) registerActions() {
+	infoAction := gio.NewSimpleAction("info", nil)
+	infoAction.ConnectActivate(func(_ *glib.Variant) {
+		a.showAboutDialog()
+	})
+	a.AddAction(infoAction)
+}
+
+func (a *Application) showAboutDialog() {
+	if a.aboutDialog == nil {
+		a.aboutDialog = a.newAboutDialog()
+	}
+
+	a.aboutDialog.Present(a.window)
+}
+
+func (a *Application) newAboutDialog() *adw.AboutDialog {
+	dialog := adw.NewAboutDialog()
+	dialog.SetApplicationName("CoverGrid")
+	dialog.SetApplicationIcon("xyz.suruatoel.mcg")
+	dialog.SetVersion(a.Version())
+	dialog.SetComments(i18n.T("CoverGrid is a client for the Music Player Daemon, focusing on albums instead of single tracks."))
+	dialog.SetWebsite("https://www.suruatoel.xyz/codes/mcg")
+	dialog.SetLicenseType(gtk.LicenseGPL30)
+	dialog.SetIssueURL("https://git.suruatoel.xyz/coderkun/mcg")
+
+	return dialog
+}
+
+func (a *Application) onActivate() {
+	if a.window == nil {
+		a.window = newMainWindow(a.Application, a.config)
+		if a.configErr != nil && !os.IsNotExist(a.configErr) {
+			a.window.SetConfigError(a.configErr)
+		}
+		a.window.ConnectCloseRequest(a.onCloseRequest)
+	}
+
+	a.window.Present()
+	if a.config.IsConnected {
+		client.Instance().Connect(a.config.Host, int(a.config.Port), a.config.Password)
+	}
+}
+
+func (a *Application) onCloseRequest() bool {
+	a.window.UpdateConfig(&a.config)
+	a.config.IsConnected = client.Instance().IsConnected()
+
+	a.saveConfig()
+
+	return false
+}
+
+func (a *Application) saveConfig() {
+	err := writeConfig(&a.config)
+	if err != nil {
+		log.Println("failed to save configuration file:", err)
+	}
+}
+
+func (a *Application) onShutdown() {
+	if client.Instance().IsConnected() {
+		client.Instance().Disconnect()
+	}
+}

internal/gui/config.go

@@ -0,0 +1,78 @@
+package gui
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+)
+
+type Configuration struct {
+	Host        string `json:"host"`
+	Port        uint64 `json:"port"`
+	Password    string `json:"password"`
+	IsConnected bool   `json:"connected"`
+	Panel       string `json:"panel"`
+	SortField   string `json:"sortField"`
+	SortDesc    bool   `json:"sortDesc"`
+	ItemSize    int    `json:"itemSize"`
+}
+
+func readConfig(config *Configuration) error {
+	filename, filenameErr := getConfigFile()
+	if filenameErr != nil {
+		return filenameErr
+	}
+
+	file, fileErr := os.Open(filename)
+	if fileErr != nil {
+		return fileErr
+	}
+	defer file.Close()
+
+	return json.NewDecoder(file).Decode(config)
+}
+
+func writeConfig(config *Configuration) error {
+	filename, filenameErr := getConfigFile()
+	if filenameErr != nil {
+		return filenameErr
+	}
+
+	file, fileErr := os.Create(filename)
+	if fileErr != nil {
+		return fileErr
+	}
+	defer file.Close()
+
+	encoder := json.NewEncoder(file)
+	encoder.SetIndent("", "\t")
+
+	return encoder.Encode(&config)
+}
+
+func getConfigFile() (string, error) {
+	configDir, configDirErr := getConfigDir()
+	if configDirErr != nil {
+		return "", configDirErr
+	}
+
+	createErr := ensureConfigDirExists(configDir)
+	if createErr != nil {
+		return "", createErr
+	}
+
+	return filepath.Join(configDir, "config.json"), nil
+}
+
+func ensureConfigDirExists(folder string) error {
+	return os.MkdirAll(folder, 0o750)
+}
+
+func getConfigDir() (string, error) {
+	configDir, configDirErr := os.UserConfigDir()
+	if configDirErr != nil {
+		return "", configDirErr
+	}
+
+	return filepath.Join(configDir, "mcg"), nil
+}

internal/gui/connectionpanel.go

@@ -0,0 +1,58 @@
+package gui
+
+import (
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+)
+
+type connectionPanel struct {
+	*adw.Bin
+
+	hostEntry     *adw.EntryRow
+	portSpinner   *gtk.SpinButton
+	passwordEntry *adw.PasswordEntryRow
+}
+
+func newConnectionPanel(config Configuration) *connectionPanel {
+	panel := connectionPanel{}
+	panel.loadWidgets()
+	panel.loadDefaultValues(config)
+	panel.connectSignals()
+
+	return &panel
+}
+
+func (p *connectionPanel) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.ConnectionPanelXML)
+
+	p.Bin = builder.GetObject("McgConnectionPanel").Cast().(*adw.Bin)
+	p.hostEntry = builder.GetObject("host_row").Cast().(*adw.EntryRow)
+	p.portSpinner = builder.GetObject("port_spinner").Cast().(*gtk.SpinButton)
+	p.passwordEntry = builder.GetObject("password_row").Cast().(*adw.PasswordEntryRow)
+}
+
+func (p *connectionPanel) connectSignals() {
+	p.hostEntry.ConnectApply(p.callback)
+	p.portSpinner.ConnectValueChanged(p.callback)
+	p.passwordEntry.ConnectApply(p.callback)
+}
+
+func (p *connectionPanel) loadDefaultValues(config Configuration) {
+	p.hostEntry.SetText(config.Host)
+	p.portSpinner.SetValue(float64(config.Port))
+	p.passwordEntry.SetText(config.Password)
+}
+
+func (p *connectionPanel) UpdateConfig(config *Configuration) {
+	config.Host = p.hostEntry.Text()
+	config.Port = uint64(p.portSpinner.Value())
+	config.Password = p.passwordEntry.Text()
+}
+
+func (p *connectionPanel) callback() {
+}
+
+func (p *connectionPanel) ConnectionDetails() (string, int, string) {
+	return p.hostEntry.Text(), p.portSpinner.ValueAsInt(), p.passwordEntry.Text()
+}

internal/gui/coverloader.go

@@ -0,0 +1,188 @@
+package gui
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+
+	"github.com/diamondburned/gotk4/pkg/core/gerror"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type CoverLoader struct {
+	hostDir string
+	size    int
+	mutex   sync.Mutex
+}
+
+func NewCoverLoader(host string) *CoverLoader {
+	loader := CoverLoader{}
+	loader.hostDir = loader.getHostDir(host)
+	loader.size = loader.readCacheSize()
+
+	return &loader
+}
+
+func (l *CoverLoader) SetSize(size int) {
+	if l.size != size {
+		log.Println("cache size has changed from", l.size, "to", size)
+		l.clearCache()
+		l.writeCacheSize(size)
+		l.size = size
+	}
+}
+
+func (l *CoverLoader) LoadThumbnail(album *common.Album) *gdkpixbuf.Pixbuf {
+	// Load cover from cache
+	pixbuf := l.getCached(album)
+	if pixbuf != nil {
+		return pixbuf
+	}
+
+	// Load cover from server
+	albumart := client.Instance().LoadAlbumartNow(album)
+	if albumart != nil {
+		pixbuf = l.loadImage(albumart)
+	}
+	if pixbuf != nil {
+		pixbuf = pixbuf.ScaleSimple(l.size, l.size, gdkpixbuf.InterpHyper)
+		if pixbuf != nil {
+			l.setCached(album, pixbuf)
+		}
+	}
+
+	return pixbuf
+}
+
+func (l *CoverLoader) getHostDir(host string) string {
+	cacheDir, cacheDirErr := os.UserCacheDir()
+	if cacheDirErr != nil {
+		log.Println("failed to detect user cache directory:", cacheDirErr)
+		return ""
+	}
+
+	hostDir := filepath.Join(cacheDir, "mcg", host)
+
+	return hostDir
+}
+
+func (l *CoverLoader) ensureHostDir() {
+	hostDirErr := os.MkdirAll(l.hostDir, 0o750)
+	if hostDirErr != nil {
+		log.Println("failed to create cache folder for host", l.hostDir, ":", hostDirErr)
+	}
+}
+
+func (l *CoverLoader) readCacheSize() int {
+	sizeFile := l.getCacheSizeFile()
+	if sizeFile == "" {
+		return 100
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+
+	content, readErr := os.ReadFile(sizeFile)
+	if readErr != nil {
+		log.Println("failed to read cache size file for host", l.hostDir, ":", readErr)
+		return 100
+	}
+
+	size, sizeErr := strconv.Atoi(string(content[:]))
+	if sizeErr != nil {
+		log.Println("invalid content of cache size file for host", l.hostDir, ":", readErr)
+	}
+
+	return size
+}
+
+func (l *CoverLoader) writeCacheSize(size int) {
+	l.ensureHostDir()
+	sizeFile := l.getCacheSizeFile()
+	if sizeFile == "" {
+		return
+	}
+
+	writeErr := os.WriteFile(sizeFile, []byte(fmt.Sprintf("%d", size)), 0o644)
+	if writeErr != nil {
+		log.Println("failed to write cache size file for host", l.hostDir, ":", writeErr)
+	}
+}
+
+func (l *CoverLoader) getCacheFile(album *common.Album) string {
+	if l.hostDir == "" {
+		return ""
+	}
+
+	return filepath.Join(l.hostDir, album.ID())
+}
+
+func (l *CoverLoader) getCacheSizeFile() string {
+	if l.hostDir == "" {
+		return ""
+	}
+
+	return filepath.Join(l.hostDir, "size")
+}
+
+func (l *CoverLoader) clearCache() {
+	if l.hostDir == "" {
+		return
+	}
+
+	removeErr := os.RemoveAll(l.hostDir)
+	if removeErr != nil {
+		log.Println("failed to clear cache folder for host", l.hostDir, ":", removeErr)
+	}
+}
+
+func (l *CoverLoader) getCached(album *common.Album) *gdkpixbuf.Pixbuf {
+	cacheFile := l.getCacheFile(album)
+	if cacheFile == "" {
+		return nil
+	}
+
+	pixbuf, pixbufErr := gdkpixbuf.NewPixbufFromFile(cacheFile)
+	if pixbufErr != nil {
+		if !isFileNotFoundError(pixbufErr) {
+			log.Println("failed to read cached thumbnail for host", l.hostDir, ":", pixbufErr)
+		}
+		return nil
+	}
+
+	return pixbuf
+}
+
+func isFileNotFoundError(err error) bool {
+	if gerr, isGerror := err.(*gerror.GError); isGerror {
+		return gerr.Quark() == uint32(glib.FileErrorQuark()) && gerr.ErrorCode() == int(glib.FileErrorNoent)
+	}
+
+	return false
+}
+
+func (l *CoverLoader) setCached(album *common.Album, pixbuf *gdkpixbuf.Pixbuf) {
+	cacheFile := l.getCacheFile(album)
+	if cacheFile == "" {
+		return
+	}
+
+	l.ensureHostDir()
+	pixbuf.Savev(cacheFile, "jpeg", []string{}, []string{})
+}
+
+func (l *CoverLoader) loadImage(file []byte) *gdkpixbuf.Pixbuf {
+	pixbufLoader, loaderErr := loadPixbuf(file)
+	if loaderErr != nil {
+		log.Println("failed to load image:", loaderErr)
+		return nil
+	}
+
+	return pixbufLoader.Pixbuf()
+}

internal/gui/coverpanel.go

@@ -0,0 +1,343 @@
+package gui
+
+import (
+	"fmt"
+	"log"
+	"math"
+	"strings"
+
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+	"suruatoel.xyz/mcg/internal/i18n"
+)
+
+type coverPanel struct {
+	*gtk.Overlay
+	toolbar          *gtk.Box
+	fullscreenButton *gtk.Button
+	coverInfoScroll  *gtk.ScrolledWindow
+	coverStack       *gtk.Stack
+	coverSpinner     *gtk.Spinner
+	coverScroll      *gtk.ScrolledWindow
+	coverBox         *gtk.Viewport
+	coverDefault     *gtk.Image
+	coverImage       *gtk.Image
+	infoRevealer     *gtk.Revealer
+	albumTitleLabel  *gtk.Label
+	albumDateLabel   *gtk.Label
+	albumArtistLabel *gtk.Label
+	songsScale       *gtk.Scale
+	currentAlbum     *common.PlaylistAlbum
+
+	currentPixbuf *gdkpixbuf.Pixbuf
+	currentWidth  int
+	currentHeight int
+
+	timer              *glib.SourceHandle
+	coverBoxController *gtk.GestureClick
+	isFullscreenActive bool
+}
+
+func newCoverPanel() *coverPanel {
+	panel := coverPanel{}
+	panel.loadWidgets()
+	panel.connectSignals()
+
+	return &panel
+}
+
+func (p *coverPanel) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.CoverPanelXML)
+
+	p.toolbar = builder.GetObject("toolbar").Cast().(*gtk.Box)
+	p.fullscreenButton = builder.GetObject("fullscreen_button").Cast().(*gtk.Button)
+	p.Overlay = builder.GetObject("McgCoverPanel").Cast().(*gtk.Overlay)
+	p.coverInfoScroll = builder.GetObject("cover_info_scroll").Cast().(*gtk.ScrolledWindow)
+	p.infoRevealer = builder.GetObject("info_revealer").Cast().(*gtk.Revealer)
+	p.albumTitleLabel = builder.GetObject("album_title_label").Cast().(*gtk.Label)
+	p.albumDateLabel = builder.GetObject("album_date_label").Cast().(*gtk.Label)
+	p.albumArtistLabel = builder.GetObject("album_artist_label").Cast().(*gtk.Label)
+	p.songsScale = builder.GetObject("songs_scale").Cast().(*gtk.Scale)
+	p.coverStack = builder.GetObject("cover_stack").Cast().(*gtk.Stack)
+	p.coverSpinner = builder.GetObject("cover_spinner").Cast().(*gtk.Spinner)
+	p.coverScroll = builder.GetObject("cover_scroll").Cast().(*gtk.ScrolledWindow)
+	p.coverBox = builder.GetObject("cover_box").Cast().(*gtk.Viewport)
+	p.coverDefault = builder.GetObject("cover_default").Cast().(*gtk.Image)
+	p.coverImage = builder.GetObject("cover_image").Cast().(*gtk.Image)
+}
+
+func (p *coverPanel) connectSignals() {
+	p.coverBoxController = gtk.NewGestureClick()
+	p.coverBox.AddController(p.coverBoxController)
+
+	buttonController := gtk.NewGestureClick()
+	buttonController.ConnectPressed(p.OnSongsScalePressed)
+	buttonController.ConnectUnpairedRelease(p.OnSongsScaleUnpairedReleased)
+	p.songsScale.AddController(buttonController)
+}
+
+func (p *coverPanel) ConnectFullscreen(callback func()) {
+	p.fullscreenButton.ConnectClicked(callback)
+	p.coverBoxController.ConnectPressed(func(nPress int, x float64, y float64) {
+		if nPress == 2 && p.currentAlbum != nil {
+			callback()
+		}
+	})
+}
+
+func (p *coverPanel) OnSongsScalePressed(nPress int, x float64, y float64) {
+	p.clearTimer()
+}
+
+func (p *coverPanel) OnSongsScaleUnpairedReleased(x float64, y float64, button uint, sequence *gdk.EventSequence) {
+	value := uint64(p.songsScale.Value())
+	time := p.currentAlbum.Length()
+	songs := p.currentAlbum.Songs()
+
+	pos := 0
+	for index := len(songs) - 1; index >= 0; index-- {
+		time = time - songs[index].Length()
+		pos = int(songs[index].Pos())
+		if time < value {
+			break
+		}
+	}
+	time = max(value-time-1, 0)
+	client.Instance().Seek(pos, time)
+}
+
+func (p *coverPanel) Toolbar() gtk.Widgetter {
+	return p.toolbar
+}
+
+func (p *coverPanel) SetPlay(pos uint64, time uint64) {
+	p.clearTimer()
+	defer p.startTimer()
+
+	dsongs := p.currentAlbum.Songs()
+	for index := range pos {
+		time += uint64(dsongs[index].Length())
+	}
+	p.songsScale.SetValue(float64(time + 1))
+}
+
+func (p *coverPanel) SetPause() {
+	p.clearTimer()
+}
+
+func (p *coverPanel) clearTimer() {
+	if p.timer != nil {
+		glib.SourceRemove(*p.timer)
+		p.timer = nil
+	}
+}
+
+func (p *coverPanel) startTimer() {
+	newTimer := glib.TimeoutAdd(1000, p.playing)
+	p.timer = &newTimer
+}
+
+func (p *coverPanel) playing() bool {
+	p.songsScale.SetValue(p.songsScale.Value() + 1)
+
+	return true
+}
+
+func (p *coverPanel) SetAlbum(state string, album *common.PlaylistAlbum) {
+	if album != nil {
+		// Set labels
+		p.albumTitleLabel.SetLabel(album.Title())
+		p.albumDateLabel.SetLabel(strings.Join(album.Dates(), ", "))
+		p.albumArtistLabel.SetLabel(strings.Join(album.Artists(), ","))
+		p.infoRevealer.SetRevealChild(true)
+
+		p.setSongs(album)
+	} else {
+		p.infoRevealer.SetRevealChild(false)
+	}
+
+	// Load cover
+	if album != nil {
+		p.coverSpinner.Start()
+		p.coverStack.SetVisibleChild(p.coverSpinner)
+
+		client.Instance().LoadAlbumart(album.Album)
+	}
+
+	// Set current album
+	p.currentAlbum = album
+	p.fullscreenButton.SetSensitive(album != nil)
+	p.enableSonglist()
+}
+
+func (p *coverPanel) Fullscreen(active bool) {
+	p.isFullscreenActive = active
+	p.enableSonglist()
+	glib.IdleAdd(p.resizeImage)
+}
+
+func (p *coverPanel) enableSonglist() {
+	enable := p.currentAlbum != nil && !p.isFullscreenActive
+
+	p.infoRevealer.SetRevealChild(enable)
+}
+
+func (p *coverPanel) SetAlbumart(album *common.Album, albumart []byte) {
+	if p.currentAlbum == nil || album != p.currentAlbum.Album {
+		return
+	}
+
+	defer glib.IdleAdd(func() {
+		p.coverStack.SetVisibleChild(p.coverScroll)
+		p.coverSpinner.Stop()
+	})
+
+	p.currentPixbuf = nil
+	if albumart == nil || len(albumart) == 0 {
+		return
+	}
+
+	loader, loaderErr := loadPixbuf(albumart)
+	if loaderErr != nil {
+		log.Println("failed to load albumart for ", album.Title(), ":", loaderErr)
+		return
+	}
+
+	p.currentPixbuf = loader.Pixbuf()
+	glib.IdleAdd(p.showImage)
+}
+
+func (p *coverPanel) showImage() {
+	if p.currentPixbuf != nil {
+		p.resizeImage()
+		p.coverStack.SetVisibleChild(p.coverScroll)
+	} else {
+		p.coverStack.SetVisibleChild(p.coverDefault)
+	}
+}
+
+func loadPixbuf(data []byte) (*gdkpixbuf.PixbufLoader, error) {
+	loader := gdkpixbuf.NewPixbufLoader()
+	defer loader.Close()
+
+	return loader, loader.Write(data)
+}
+
+func (p *coverPanel) setSongs(album *common.PlaylistAlbum) {
+	p.songsScale.ClearMarks()
+	p.songsScale.SetRange(0, float64(album.Length()))
+
+	length := uint64(0)
+	for _, song := range album.Songs() {
+		curLength := length
+		if length > 0 && length < album.Length() {
+			curLength += 1
+		}
+		songTitle := createSongTitle(song)
+		p.songsScale.AddMark(
+			float64(curLength),
+			gtk.PosRight,
+			glib.MarkupEscapeText(songTitle),
+		)
+		length += song.Length()
+	}
+
+	p.songsScale.AddMark(float64(length), gtk.PosRight, createAlbumLengthTitle(length))
+	p.alignSongsScaleMarks()
+}
+
+func (p *coverPanel) alignSongsScaleMarks() {
+	p.alignScaleMarks(&p.songsScale.Widget)
+}
+
+func (p *coverPanel) alignScaleMarks(widgetter gtk.Widgetter) {
+	widget := widgetter.(*gtk.Widget)
+	child := widget.FirstChild()
+	for child != nil {
+		if label, isLabel := child.(*gtk.Label); isLabel {
+			label.SetHAlign(gtk.AlignStart)
+			child = label.NextSibling()
+		} else {
+			p.alignScaleMarks(child)
+			child = child.(*gtk.Widget).NextSibling()
+		}
+	}
+}
+
+func createSongTitle(song *common.PlaylistSong) string {
+	songArtists := song.SongArtists()
+	if len(songArtists) > 0 {
+		return fmt.Sprintf(
+			i18n.T("%s feat. %s"),
+			song.Title(),
+			strings.Join(songArtists, ", "),
+		)
+	}
+
+	return song.Title()
+}
+
+func createAlbumLengthTitle(length uint64) string {
+	minutes := length / 60
+	seconds := length % 60
+
+	return fmt.Sprintf(i18n.T("%d:%d minutes"), minutes, seconds)
+}
+
+func (p *coverPanel) SetWidth(width int) {
+	glib.IdleAdd(p.resizeImage)
+	glib.IdleAdd(func() {
+		p.coverInfoScroll.SetMaxContentWidth(width / 2)
+	})
+}
+
+func (p *coverPanel) resizeImage() {
+	newWidth, newHeight := p.getSize()
+	if p.hasSizeChanged(newWidth, newHeight) {
+		return
+	}
+	p.setSize(newWidth, newHeight)
+
+	if p.currentPixbuf == nil {
+		p.coverImage.SetPixelSize(min(newWidth, newHeight))
+		return
+	}
+
+	width, height := p.calculateCoverSize()
+	if width <= 0 || height <= 0 {
+		return
+	}
+
+	scaledPixbuf := p.currentPixbuf.ScaleSimple(width, height, gdkpixbuf.InterpHyper)
+	p.coverImage.SetFromPaintable(gdk.NewTextureForPixbuf(scaledPixbuf))
+	p.coverImage.SetPixelSize(min(width, height))
+}
+
+func (p *coverPanel) getSize() (int, int) {
+	return p.coverStack.Size(gtk.OrientationHorizontal), p.coverStack.Size(gtk.OrientationVertical)
+}
+
+func (p *coverPanel) hasSizeChanged(newWidth, newHeight int) bool {
+	return newWidth == p.currentWidth && newHeight == p.currentHeight
+}
+
+func (p *coverPanel) setSize(newWidth, newHeight int) {
+	p.currentWidth = newWidth
+	p.currentHeight = newHeight
+}
+
+func (p *coverPanel) calculateCoverSize() (width, height int) {
+	ratioWidth := float64(p.currentWidth) / float64(p.currentPixbuf.Width())
+	ratioHeight := float64(p.currentHeight) / float64(p.currentPixbuf.Height())
+	ratio := min(min(ratioWidth, ratioHeight), 1)
+
+	width = int(math.Floor(float64(p.currentPixbuf.Width()) * ratio))
+	height = int(math.Floor(float64(p.currentPixbuf.Height()) * ratio))
+
+	return
+}

internal/gui/librarypanel.go

@@ -0,0 +1,563 @@
+package gui
+
+import (
+	"log"
+	"math"
+	"slices"
+	"strings"
+	"sync"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type libraryPanel struct {
+	*adw.Bin
+	toolbar           *gtk.Box
+	selectButton      *gtk.ToggleButton
+	actionbarRevealer *gtk.Revealer
+	toolbarPopover    *gtk.Popover
+	searchBar         *gtk.SearchBar
+	searchEntry       *gtk.SearchEntry
+	sortButtons       map[string]*gtk.CheckButton
+	sortDescButton    *gtk.CheckButton
+	gridScale         *gtk.Scale
+	stack             *gtk.Stack
+	progressBox       *gtk.Box
+	progressBar       *gtk.ProgressBar
+	scroll            *gtk.ScrolledWindow
+	libraryGrid       *gtk.GridView
+	gridFactory       *pictureItemFactory[string]
+	libraryModel      *gtk.StringList
+	selectionMulti    *gtk.MultiSelection
+	selectionSingle   *gtk.SingleSelection
+
+	headerbarStandalone   *albumHeaderbar
+	libraryStack          *gtk.Stack
+	panelNormal           *gtk.Box
+	panelStandalone       *gtk.Box
+	standaloneStack       *gtk.Stack
+	standaloneSpinner     *gtk.Spinner
+	standaloneScroll      *gtk.ScrolledWindow
+	standaloneImage       *gtk.Image
+	standalonePlayButton  *gtk.Button
+	standaloneQueueButton *gtk.Button
+	selectionQueueButton  *gtk.Button
+	selectionCancelButton *gtk.Button
+
+	coverLoader      *CoverLoader
+	albums           map[string]*common.Album
+	pixbufs          map[string]*gdkpixbuf.Pixbuf
+	sortField        string
+	sortDesc         bool
+	itemSize         int
+	itemSizeCallback ItemSizeCallback
+
+	libraryLock sync.Mutex
+	libraryWait sync.WaitGroup
+
+	standaloneAlbum    *common.Album
+	standalonePixbuf   *gdkpixbuf.Pixbuf
+	standaloneCallback func(bool)
+}
+
+type ItemSizeCallback func(itemSize int)
+
+func newLibraryPanel(config Configuration) *libraryPanel {
+	panel := libraryPanel{
+		albums:      make(map[string]*common.Album),
+		pixbufs:     make(map[string]*gdkpixbuf.Pixbuf),
+		sortField:   "year",
+		sortDesc:    false,
+		libraryLock: sync.Mutex{},
+		libraryWait: sync.WaitGroup{},
+	}
+	panel.loadWidgets(config)
+	panel.loadDefaultValues(config)
+	panel.connectSignals()
+
+	return &panel
+}
+
+func (p *libraryPanel) loadWidgets(config Configuration) {
+	builder := gtk.NewBuilderFromString(data.LibraryPanelXML)
+
+	p.toolbar = builder.GetObject("toolbar").Cast().(*gtk.Box)
+	p.selectButton = builder.GetObject("select_button").Cast().(*gtk.ToggleButton)
+	p.actionbarRevealer = builder.GetObject("actionbar_revealer").Cast().(*gtk.Revealer)
+	p.toolbarPopover = builder.GetObject("toolbar_popover").Cast().(*gtk.Popover)
+
+	p.searchBar = builder.GetObject("filter_bar").Cast().(*gtk.SearchBar)
+	p.searchEntry = builder.GetObject("filter_entry").Cast().(*gtk.SearchEntry)
+	p.sortButtons = make(map[string]*gtk.CheckButton)
+	p.sortButtons["artist"] = builder.GetObject("sort_artist").Cast().(*gtk.CheckButton)
+	p.sortButtons["title"] = builder.GetObject("sort_title").Cast().(*gtk.CheckButton)
+	p.sortButtons["year"] = builder.GetObject("sort_year").Cast().(*gtk.CheckButton)
+	p.sortButtons["modified"] = builder.GetObject("sort_modified").Cast().(*gtk.CheckButton)
+	p.sortDescButton = builder.GetObject("toolbar_sort_order_button").Cast().(*gtk.CheckButton)
+	p.gridScale = builder.GetObject("grid_scale").Cast().(*gtk.Scale)
+
+	p.Bin = builder.GetObject("McgLibraryPanel").Cast().(*adw.Bin)
+	p.stack = builder.GetObject("stack").Cast().(*gtk.Stack)
+	p.progressBox = builder.GetObject("progress_box").Cast().(*gtk.Box)
+	p.progressBar = builder.GetObject("progress_bar").Cast().(*gtk.ProgressBar)
+	p.scroll = builder.GetObject("scroll").Cast().(*gtk.ScrolledWindow)
+	p.libraryGrid = builder.GetObject("library_grid").Cast().(*gtk.GridView)
+	p.libraryModel = gtk.NewStringList(nil)
+	p.selectionMulti = gtk.NewMultiSelection(p.libraryModel)
+	p.selectionSingle = gtk.NewSingleSelection(p.libraryModel)
+	p.libraryGrid.SetModel(p.selectionSingle)
+
+	p.gridFactory = newPictureItemFactory[string](p.itemToModelID, p.modelIDToValue)
+	p.libraryGrid.SetFactory(p.gridFactory.ListItemFactory())
+
+	// Headerbar
+	p.headerbarStandalone = newAlbumHeaderbar()
+	p.libraryStack = builder.GetObject("library_stack").Cast().(*gtk.Stack)
+	p.panelNormal = builder.GetObject("panel_normal").Cast().(*gtk.Box)
+	p.panelStandalone = builder.GetObject("panel_standalone").Cast().(*gtk.Box)
+
+	p.standaloneStack = builder.GetObject("standalone_stack").Cast().(*gtk.Stack)
+	p.standaloneSpinner = builder.GetObject("standalone_spinner").Cast().(*gtk.Spinner)
+	p.standaloneScroll = builder.GetObject("standalone_scroll").Cast().(*gtk.ScrolledWindow)
+	p.standaloneImage = builder.GetObject("standalone_image").Cast().(*gtk.Image)
+	p.standalonePlayButton = builder.GetObject("standalone_play_button").Cast().(*gtk.Button)
+	p.standaloneQueueButton = builder.GetObject("standalone_queue_button").Cast().(*gtk.Button)
+
+	// Selection
+	p.selectionQueueButton = builder.GetObject("selection_queue_button").Cast().(*gtk.Button)
+	p.selectionCancelButton = builder.GetObject("selection_cancel_button").Cast().(*gtk.Button)
+}
+
+func (p *libraryPanel) itemToModelID(item *glib.Object) string {
+	return item.Cast().(*gtk.StringObject).String()
+}
+
+func (p *libraryPanel) modelIDToValue(itemID string) (tooltip string, pixbuf *gdkpixbuf.Pixbuf) {
+	if album, ok := p.albums[itemID]; ok {
+		tooltip = album.Tooltip()
+	}
+	pixbuf = p.pixbufs[itemID]
+
+	return
+}
+
+func (p *libraryPanel) loadDefaultValues(config Configuration) {
+	p.itemSize = config.ItemSize
+	p.gridScale.SetValue(float64(config.ItemSize))
+
+	_, found := p.sortButtons[config.SortField]
+	if found {
+		p.sortField = config.SortField
+	}
+	p.sortDesc = config.SortDesc
+
+	p.sortButtons[p.sortField].SetActive(true)
+	p.sortDescButton.SetActive(p.sortDesc)
+}
+
+func (p *libraryPanel) connectSignals() {
+	p.selectButton.ConnectToggled(p.onSelectToggled)
+	p.searchEntry.ConnectSearchChanged(p.onFilterEntryChanged)
+	for field, button := range p.sortButtons {
+		button.ConnectToggled(func() {
+			p.onSortToggled(field, button)
+		})
+	}
+	p.sortDescButton.ConnectToggled(p.onSortDescToggled)
+
+	p.libraryGrid.ConnectActivate(p.onGridClicked)
+
+	p.headerbarStandalone.ConnectClose(p.onHeaderbarStandaloneClose)
+	p.standalonePlayButton.ConnectClicked(p.onStandalonePlayClicked)
+	p.standaloneQueueButton.ConnectClicked(p.onStandaloneQueueClicked)
+
+	p.selectionQueueButton.ConnectClicked(p.onSelectionQueue)
+	p.selectionCancelButton.ConnectClicked(p.onSelectionCancel)
+
+	buttonController := gtk.NewGestureClick()
+	buttonController.ConnectUnpairedRelease(p.onGridScaleReleased)
+	p.gridScale.AddController(buttonController)
+	p.gridScale.ConnectValueChanged(p.onGridScaleChanged)
+}
+
+func (p *libraryPanel) ConnectItemSizeChanged(callback ItemSizeCallback) {
+	p.itemSizeCallback = callback
+}
+
+func (p *libraryPanel) ConnectStandalone(callback func(bool)) {
+	p.standaloneCallback = callback
+}
+
+func (p *libraryPanel) onSelectToggled() {
+	if p.selectButton.Active() {
+		p.actionbarRevealer.SetRevealChild(true)
+		p.libraryGrid.SetModel(p.selectionMulti)
+		p.libraryGrid.SetSingleClickActivate(false)
+		p.libraryGrid.StyleContext().AddClass("selection")
+	} else {
+		p.actionbarRevealer.SetRevealChild(false)
+		p.libraryGrid.SetModel(p.selectionSingle)
+		p.libraryGrid.SetSingleClickActivate(true)
+		p.libraryGrid.StyleContext().RemoveClass("selection")
+	}
+}
+
+func (p *libraryPanel) onFilterEntryChanged() {
+	p.updateGridModel()
+}
+
+func (p *libraryPanel) onSortToggled(field string, button *gtk.CheckButton) {
+	if !button.Active() {
+		return
+	}
+
+	p.sortField = field
+	p.updateGridModel()
+}
+
+func (p *libraryPanel) onSortDescToggled() {
+	p.sortDesc = p.sortDescButton.Active()
+	p.updateGridModel()
+}
+
+func (p *libraryPanel) onGridScaleChanged() {
+	size := math.Floor(p.gridScale.Value())
+	gridRange := p.gridScale.Adjustment()
+	if size < gridRange.Lower() || size > gridRange.Upper() {
+		return
+	}
+
+	go p.setGridSize(int(size))
+}
+
+func (p *libraryPanel) setGridSize(size int) {
+	if size == p.itemSize {
+		return
+	}
+
+	for i := range p.libraryGrid.Model().NItems() {
+		itemObj := p.libraryGrid.Model().Item(i)
+		if itemObj != nil {
+			itemStr := itemObj.Cast().(*gtk.StringObject)
+			albumID := itemStr.String()
+			picture, pictureFound := p.gridFactory.Picture(albumID)
+			if pictureFound {
+				pixbuf, pixbufFound := p.pixbufs[albumID]
+				if pixbufFound {
+					if pixbuf != nil {
+						pixbuf = pixbuf.ScaleSimple(size, size, gdkpixbuf.InterpNearest)
+					} else {
+					}
+					glib.IdleAdd(func() {
+						picture.SetPaintable(gdk.NewTextureForPixbuf(pixbuf))
+					})
+				}
+			}
+		}
+	}
+}
+
+func (p *libraryPanel) onGridScaleReleased(x float64, y float64, button uint, sequence *gdk.EventSequence) {
+	size := math.Floor(p.gridScale.Value())
+	gridRange := p.gridScale.Adjustment()
+	if size < gridRange.Lower() || size > gridRange.Upper() {
+		return
+	}
+
+	p.itemSize = int(size)
+	p.redraw()
+	glib.IdleAdd(p.toolbarPopover.Popdown)
+	if p.itemSizeCallback != nil {
+		p.itemSizeCallback(p.itemSize)
+	}
+}
+
+func (p *libraryPanel) redraw() {
+	if len(p.albums) > 0 {
+		p.SetAlbums(p.albums)
+	}
+}
+
+func (p *libraryPanel) onGridClicked(position uint) {
+	// Get selected album
+	itemObj := p.libraryModel.Item(position)
+	if itemObj == nil {
+		return
+	}
+	strObj := itemObj.Cast().(*gtk.StringObject)
+	id := strObj.String()
+	album, found := p.albums[id]
+	if !found {
+		return
+	}
+
+	// Show standalone album
+	if p.libraryGrid.Model().Native() == p.selectionSingle.Native() {
+		p.standaloneAlbum = album
+		p.headerbarStandalone.SetAlbum(album)
+		p.standaloneStack.SetVisibleChild(p.standaloneSpinner)
+		p.standaloneSpinner.Start()
+		p.openStandalone()
+		client.Instance().LoadAlbumart(album)
+	}
+}
+
+func (p *libraryPanel) onHeaderbarStandaloneClose() {
+	p.closeStandalone()
+}
+
+func (p *libraryPanel) openStandalone() {
+	p.libraryStack.SetVisibleChild(p.panelStandalone)
+	if p.standaloneCallback != nil {
+		p.standaloneCallback(true)
+	}
+}
+
+func (p *libraryPanel) closeStandalone() {
+	p.libraryStack.SetVisibleChild(p.panelNormal)
+	if p.standaloneCallback != nil {
+		p.standaloneCallback(false)
+	}
+}
+
+func (p *libraryPanel) setCoverLoader(loader *CoverLoader) {
+	p.coverLoader = loader
+}
+
+func (p *libraryPanel) SetAlbumart(album *common.Album, albumart []byte) {
+	if album != p.standaloneAlbum {
+		return
+	}
+
+	p.standalonePixbuf = nil
+	if albumart == nil || len(albumart) == 0 {
+		return
+	}
+
+	loader, loaderErr := loadPixbuf(albumart)
+	if loaderErr != nil {
+		log.Println("failed to load albumart for ", album.Title(), ":", loaderErr)
+		return
+	}
+
+	p.standalonePixbuf = loader.Pixbuf()
+	glib.IdleAdd(p.showStandaloneImage)
+}
+
+func (p *libraryPanel) showStandaloneImage() {
+	p.resizeStandaloneImage()
+	p.standaloneStack.SetVisibleChild(p.standaloneScroll)
+	p.standaloneSpinner.Stop()
+}
+
+func (p *libraryPanel) resizeStandaloneImage() {
+	newWidth, newHeight := p.getStandaloneSize()
+	if p.standalonePixbuf == nil {
+		p.standaloneImage.SetPixelSize(min(newWidth, newHeight))
+		return
+	}
+
+	width, height := p.calculateCoverSize(newWidth, newHeight)
+	if width <= 0 || height <= 0 {
+		return
+	}
+
+	scaledPixbuf := p.standalonePixbuf.ScaleSimple(width, height, gdkpixbuf.InterpHyper)
+	p.standaloneImage.SetFromPaintable(gdk.NewTextureForPixbuf(scaledPixbuf))
+	p.standaloneImage.SetPixelSize(min(width, height))
+}
+
+func (p *libraryPanel) getStandaloneSize() (int, int) {
+	return p.standaloneStack.Size(gtk.OrientationHorizontal), p.standaloneStack.Size(gtk.OrientationVertical)
+}
+
+func (p *libraryPanel) calculateCoverSize(currentWidth, currentHeight int) (width, height int) {
+	ratioWidth := float64(currentWidth) / float64(p.standalonePixbuf.Width())
+	ratioHeight := float64(currentHeight) / float64(p.standalonePixbuf.Height())
+	ratio := min(min(ratioWidth, ratioHeight), 1)
+
+	width = int(math.Floor(float64(p.standalonePixbuf.Width()) * ratio))
+	height = int(math.Floor(float64(p.standalonePixbuf.Height()) * ratio))
+
+	return
+}
+
+func (p *libraryPanel) onStandalonePlayClicked() {
+	client.Instance().PlayAlbum(p.standaloneAlbum)
+	p.closeStandalone()
+}
+
+func (p *libraryPanel) onStandaloneQueueClicked() {
+	client.Instance().QueueAlbum(p.standaloneAlbum)
+	p.closeStandalone()
+}
+
+func (p *libraryPanel) onSelectionQueue() {
+	albums := p.getSelectedAlbums()
+	if len(albums) > 0 {
+		client.Instance().QueueAlbums(albums)
+	}
+
+	p.selectButton.SetActive(false)
+}
+
+func (p *libraryPanel) onSelectionCancel() {
+	p.selectButton.SetActive(false)
+}
+
+func (p *libraryPanel) getSelectedAlbums() []*common.Album {
+	albums := []*common.Album{}
+	for i := range p.selectionMulti.NItems() {
+		if p.selectionMulti.IsSelected(i) {
+			itemObj := p.selectionMulti.Item(i)
+			if itemObj != nil {
+				itemStr := itemObj.Cast().(*gtk.StringObject)
+				albumID := itemStr.String()
+				album, found := p.albums[albumID]
+				if found {
+					albums = append(albums, album)
+				}
+			}
+		}
+	}
+
+	return albums
+}
+
+func (p *libraryPanel) UpdateConfig(config *Configuration) {
+	config.SortField = p.sortField
+	config.SortDesc = p.sortDesc
+	config.ItemSize = p.itemSize
+}
+
+func (p *libraryPanel) updateGridModel() {
+	albums := p.filterAlbums()
+	p.sortAlbums(albums)
+	p.updateGrid(albums)
+}
+
+func (p *libraryPanel) filterAlbums() []*common.Album {
+	var matchingAlbums []*common.Album
+	query := strings.TrimSpace(strings.ToLower(p.searchEntry.Text()))
+	for _, album := range p.albums {
+		if album.IsMatch(query) {
+			matchingAlbums = append(matchingAlbums, album)
+		}
+	}
+
+	return matchingAlbums
+}
+
+func (p *libraryPanel) sortAlbums(filtered []*common.Album) {
+	common.SortAlbums(filtered, p.sortField)
+
+	if p.sortDesc {
+		slices.Reverse(filtered)
+	}
+}
+
+func (p *libraryPanel) updateGrid(albums []*common.Album) {
+	glib.IdleAdd(func() {
+		n := p.libraryModel.NItems()
+		if n > 0 {
+			p.libraryModel.Splice(0, n, nil)
+		}
+
+		ids := make([]string, 0, len(albums))
+		for _, item := range albums {
+			ids = append(ids, item.ID())
+		}
+
+		if len(ids) > 0 {
+			p.libraryModel.Splice(0, 0, ids)
+		}
+	})
+}
+
+func (p *libraryPanel) Toolbar() gtk.Widgetter {
+	return p.toolbar
+}
+
+func (p *libraryPanel) Wait() {
+	p.libraryWait.Wait()
+}
+
+type LibraryFactory gtk.ListItemFactory
+
+func (p *libraryPanel) SetAlbums(albums map[string]*common.Album) {
+	p.libraryWait.Add(1)
+	go p.setAlbums(albums)
+}
+
+func (p *libraryPanel) setAlbums(albums map[string]*common.Album) {
+	p.libraryLock.Lock()
+	defer p.libraryLock.Unlock()
+	defer p.libraryWait.Done()
+
+	p.albums = albums
+	glib.IdleAdd(func() {
+		p.stack.SetVisibleChild(p.progressBox)
+		p.progressBar.SetFraction(0.0)
+	})
+
+	// Create loader loader
+	i := 0
+	n := len(albums)
+	p.pixbufs = make(map[string]*gdkpixbuf.Pixbuf)
+
+	for _, album := range albums {
+		if p.coverLoader != nil {
+			p.pixbufs[album.ID()] = p.coverLoader.LoadThumbnail(album)
+		}
+
+		i++
+		glib.IdleAdd(func() {
+			p.progressBar.SetFraction(float64(i) / float64(n))
+			// FIXME: i18n
+			p.progressBar.SetText("Loading images")
+		})
+	}
+
+	p.updateGridModel()
+	glib.IdleAdd(func() {
+		p.stack.SetVisibleChild(p.scroll)
+	})
+}
+
+func (p *libraryPanel) SetWidth(width int) {
+	p.resizeStandaloneImage()
+	p.setMarks(width)
+}
+
+func (p *libraryPanel) setMarks(width int) {
+	glib.IdleAdd(func() {
+		p.gridScale.ClearMarks()
+	})
+
+	lower := p.gridScale.Adjustment().Lower()
+	upper := p.gridScale.Adjustment().Upper()
+	countMin := int(math.Max(float64(width)/upper, 1))
+	countMax := int(math.Max(float64(width)/lower, 1))
+	for i := countMin; i <= countMax; i++ {
+		pixel := int(float64(width) / float64(i))
+		pixel = pixel - (2 * pixel / 100)
+		glib.IdleAdd(func() {
+			p.gridScale.AddMark(float64(pixel), gtk.PosBottom, "")
+		})
+	}
+}
+
+func (p *libraryPanel) ShowSearch() {
+	p.searchBar.SetSearchMode(true)
+}
+
+func (p *libraryPanel) HeaderbarStandalone() *albumHeaderbar {
+	return p.headerbarStandalone
+}

internal/gui/pictureitemfactory.go

@@ -0,0 +1,78 @@
+package gui
+
+import (
+	"github.com/diamondburned/gotk4/pkg/core/glib"
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+)
+
+type pictureItemFactory[T comparable] struct {
+	model           modelAccessor[T]
+	value           valueAccessor[T]
+	listItemFactory *gtk.SignalListItemFactory
+	pictures        map[T]*gtk.Picture
+}
+
+type (
+	modelAccessor[T any] func(item *glib.Object) T
+	valueAccessor[T any] func(T) (tooltip string, pixbuf *gdkpixbuf.Pixbuf)
+)
+
+func newPictureItemFactory[T comparable](model modelAccessor[T], value valueAccessor[T]) *pictureItemFactory[T] {
+	factory := pictureItemFactory[T]{
+		model:           model,
+		value:           value,
+		listItemFactory: gtk.NewSignalListItemFactory(),
+		pictures:        make(map[T]*gtk.Picture),
+	}
+	factory.listItemFactory.Connect("setup", factory.setup)
+	factory.listItemFactory.Connect("bind", factory.bind)
+	factory.listItemFactory.Connect("unbind", factory.unbind)
+
+	return &factory
+}
+
+func (f *pictureItemFactory[T]) setup(listitem *gtk.ListItem) {
+	picture := gtk.NewPicture()
+	picture.SetContentFit(gtk.ContentFitContain)
+	picture.SetCanShrink(false)
+	listitem.SetChild(picture)
+}
+
+func (f *pictureItemFactory[T]) bind(listitem *gtk.ListItem) {
+	item := listitem.Item()
+	if item == nil {
+		return
+	}
+	itemID := f.model(item)
+
+	tooltip, pixbuf := f.value(itemID)
+	picture := listitem.Child().(*gtk.Picture)
+	picture.SetTooltipText(tooltip)
+	if pixbuf != nil {
+		picture.SetPaintable(gdk.NewTextureForPixbuf(pixbuf))
+	}
+
+	f.pictures[itemID] = picture
+}
+
+func (f *pictureItemFactory[T]) unbind(listitem *gtk.ListItem) {
+	itemObj := listitem.Item()
+	if itemObj == nil {
+		return
+	}
+
+	itemID := f.model(itemObj)
+	delete(f.pictures, itemID)
+}
+
+func (f *pictureItemFactory[T]) ListItemFactory() *gtk.ListItemFactory {
+	return &f.listItemFactory.ListItemFactory
+}
+
+func (f *pictureItemFactory[T]) Picture(itemID T) (*gtk.Picture, bool) {
+	picture, found := f.pictures[itemID]
+
+	return picture, found
+}

internal/gui/playlistpanel.go

@@ -0,0 +1,358 @@
+package gui
+
+import (
+	"log"
+	"math"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type playlistPanel struct {
+	*adw.Bin
+	toolbar           *gtk.Box
+	selectButton      *gtk.ToggleButton
+	actionbarRevealer *gtk.Revealer
+	clearButton       *gtk.Button
+	playlistGrid      *gtk.GridView
+	gridFactory       *pictureItemFactory[string]
+	playlistModel     *gtk.StringList
+	selectionMulti    *gtk.MultiSelection
+	selectionSingle   *gtk.SingleSelection
+
+	headerbarStandalone    *albumHeaderbar
+	playlistStack          *gtk.Stack
+	panelNormal            *gtk.Box
+	panelStandalone        *gtk.Box
+	standaloneStack        *gtk.Stack
+	standaloneSpinner      *gtk.Spinner
+	standaloneScroll       *gtk.ScrolledWindow
+	standaloneImage        *gtk.Image
+	standalonePlayButton   *gtk.Button
+	standaloneRemoveButton *gtk.Button
+
+	selectionRemoveButton *gtk.Button
+	selectionCancelButton *gtk.Button
+
+	coverLoader *CoverLoader
+	playlist    []*common.PlaylistAlbum
+	albums      map[string]*common.PlaylistAlbum
+	pixbufs     map[string]*gdkpixbuf.Pixbuf
+
+	standaloneAlbum    *common.PlaylistAlbum
+	standalonePixbuf   *gdkpixbuf.Pixbuf
+	standaloneCallback func(bool)
+}
+
+func newPlaylistPanel() *playlistPanel {
+	panel := playlistPanel{
+		albums:  make(map[string]*common.PlaylistAlbum),
+		pixbufs: make(map[string]*gdkpixbuf.Pixbuf),
+	}
+	panel.loadWidgets()
+	panel.connectSignals()
+
+	return &panel
+}
+
+func (p *playlistPanel) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.PlaylistPanelXML)
+
+	p.toolbar = builder.GetObject("toolbar").Cast().(*gtk.Box)
+	p.selectButton = builder.GetObject("select_button").Cast().(*gtk.ToggleButton)
+	p.actionbarRevealer = builder.GetObject("actionbar_revealer").Cast().(*gtk.Revealer)
+	p.clearButton = builder.GetObject("playlist_clear_button").Cast().(*gtk.Button)
+
+	p.Bin = builder.GetObject("McgPlaylistPanel").Cast().(*adw.Bin)
+	p.playlistGrid = builder.GetObject("playlist_grid").Cast().(*gtk.GridView)
+	p.playlistModel = gtk.NewStringList(nil)
+	p.selectionMulti = gtk.NewMultiSelection(p.playlistModel)
+	p.selectionSingle = gtk.NewSingleSelection(p.playlistModel)
+	p.playlistGrid.SetModel(p.selectionSingle)
+
+	p.gridFactory = newPictureItemFactory[string](p.itemToModelID, p.modelIDToValue)
+	p.playlistGrid.SetFactory(p.gridFactory.ListItemFactory())
+
+	// Headerbar
+	p.headerbarStandalone = newAlbumHeaderbar()
+	p.playlistStack = builder.GetObject("playlist_stack").Cast().(*gtk.Stack)
+	p.panelNormal = builder.GetObject("panel_normal").Cast().(*gtk.Box)
+	p.panelStandalone = builder.GetObject("panel_standalone").Cast().(*gtk.Box)
+
+	p.standaloneStack = builder.GetObject("standalone_stack").Cast().(*gtk.Stack)
+	p.standaloneSpinner = builder.GetObject("standalone_spinner").Cast().(*gtk.Spinner)
+	p.standaloneScroll = builder.GetObject("standalone_scroll").Cast().(*gtk.ScrolledWindow)
+	p.standaloneImage = builder.GetObject("standalone_image").Cast().(*gtk.Image)
+	p.standalonePlayButton = builder.GetObject("standalone_play_button").Cast().(*gtk.Button)
+	p.standaloneRemoveButton = builder.GetObject("standalone_remove_button").Cast().(*gtk.Button)
+
+	// Selection
+	p.selectionRemoveButton = builder.GetObject("selection_remove_button").Cast().(*gtk.Button)
+	p.selectionCancelButton = builder.GetObject("selection_cancel_button").Cast().(*gtk.Button)
+}
+
+func (p *playlistPanel) itemToModelID(item *glib.Object) string {
+	return item.Cast().(*gtk.StringObject).String()
+}
+
+func (p *playlistPanel) modelIDToValue(itemID string) (tooltip string, pixbuf *gdkpixbuf.Pixbuf) {
+	if album, ok := p.albums[itemID]; ok {
+		tooltip = album.Tooltip()
+	}
+	pixbuf = p.pixbufs[itemID]
+
+	return
+}
+
+func (p *playlistPanel) connectSignals() {
+	p.selectButton.ConnectToggled(p.onSelectToggled)
+	p.clearButton.ConnectClicked(p.onClearClicked)
+
+	p.playlistGrid.ConnectActivate(p.onGridClicked)
+
+	p.headerbarStandalone.ConnectClose(p.onHeaderbarStandaloneClose)
+	p.standalonePlayButton.ConnectClicked(p.onStandalonePlayClicked)
+	p.standaloneRemoveButton.ConnectClicked(p.onStandaloneRemoveClicked)
+
+	p.selectionRemoveButton.ConnectClicked(p.onSelectionRemove)
+	p.selectionCancelButton.ConnectClicked(p.onSelectionCancel)
+}
+
+func (p *playlistPanel) ConnectStandalone(callback func(bool)) {
+	p.standaloneCallback = callback
+}
+
+func (p *playlistPanel) onSelectToggled() {
+	if p.selectButton.Active() {
+		p.actionbarRevealer.SetRevealChild(true)
+		p.playlistGrid.SetModel(p.selectionMulti)
+		p.playlistGrid.SetSingleClickActivate(false)
+		p.playlistGrid.StyleContext().AddClass("selection")
+	} else {
+		p.actionbarRevealer.SetRevealChild(false)
+		p.playlistGrid.SetModel(p.selectionSingle)
+		p.playlistGrid.SetSingleClickActivate(true)
+		p.playlistGrid.StyleContext().AddClass("selection")
+	}
+}
+
+func (p *playlistPanel) onClearClicked() {
+	client.Instance().ClearPlaylist()
+}
+
+func (p *playlistPanel) onGridClicked(position uint) {
+	// Get selected album
+	itemObj := p.playlistModel.Item(position)
+	if itemObj == nil {
+		return
+	}
+	strObj := itemObj.Cast().(*gtk.StringObject)
+	id := strObj.String()
+	album, found := p.albums[id]
+	if !found {
+		return
+	}
+
+	// Show standalone album
+	if p.playlistGrid.Model().Native() == p.selectionSingle.Native() {
+		p.standaloneAlbum = album
+		p.headerbarStandalone.SetAlbum(album.Album)
+		p.standaloneStack.SetVisibleChild(p.standaloneSpinner)
+		p.standaloneSpinner.Start()
+		p.openStandalone()
+		client.Instance().LoadAlbumart(album.Album)
+	}
+}
+
+func (p *playlistPanel) onHeaderbarStandaloneClose() {
+	p.closeStandalone()
+}
+
+func (p *playlistPanel) openStandalone() {
+	p.playlistStack.SetVisibleChild(p.panelStandalone)
+	if p.standaloneCallback != nil {
+		p.standaloneCallback(true)
+	}
+}
+
+func (p *playlistPanel) closeStandalone() {
+	p.playlistStack.SetVisibleChild(p.panelNormal)
+	if p.standaloneCallback != nil {
+		p.standaloneCallback(false)
+	}
+}
+
+func (p *playlistPanel) setCoverLoader(loader *CoverLoader) {
+	p.coverLoader = loader
+}
+
+func (p *playlistPanel) SetAlbumart(album *common.Album, albumart []byte) {
+	if p.standaloneAlbum == nil || album != p.standaloneAlbum.Album {
+		return
+	}
+
+	p.standalonePixbuf = nil
+	if albumart == nil || len(albumart) == 0 {
+		return
+	}
+
+	loader, loaderErr := loadPixbuf(albumart)
+	if loaderErr != nil {
+		log.Println("failed to load albumart for ", album.Title(), ":", loaderErr)
+		return
+	}
+
+	p.standalonePixbuf = loader.Pixbuf()
+	glib.IdleAdd(p.showStandaloneImage)
+}
+
+func (p *playlistPanel) showStandaloneImage() {
+	p.resizeStandaloneImage()
+	p.standaloneStack.SetVisibleChild(p.standaloneScroll)
+	p.standaloneSpinner.Stop()
+}
+
+func (p *playlistPanel) resizeStandaloneImage() {
+	newWidth, newHeight := p.getStandaloneSize()
+	if p.standalonePixbuf == nil {
+		p.standaloneImage.SetPixelSize(min(newWidth, newHeight))
+		return
+	}
+
+	width, height := p.calculateCoverSize(newWidth, newHeight)
+	if width <= 0 || height <= 0 {
+		return
+	}
+
+	scaledPixbuf := p.standalonePixbuf.ScaleSimple(width, height, gdkpixbuf.InterpHyper)
+	p.standaloneImage.SetFromPaintable(gdk.NewTextureForPixbuf(scaledPixbuf))
+	p.standaloneImage.SetPixelSize(min(width, height))
+}
+
+func (p *playlistPanel) getStandaloneSize() (int, int) {
+	return p.standaloneStack.Size(gtk.OrientationHorizontal), p.standaloneStack.Size(gtk.OrientationVertical)
+}
+
+func (p *playlistPanel) calculateCoverSize(currentWidth, currentHeight int) (width, height int) {
+	ratioWidth := float64(currentWidth) / float64(p.standalonePixbuf.Width())
+	ratioHeight := float64(currentHeight) / float64(p.standalonePixbuf.Height())
+	ratio := min(min(ratioWidth, ratioHeight), 1)
+
+	width = int(math.Floor(float64(p.standalonePixbuf.Width()) * ratio))
+	height = int(math.Floor(float64(p.standalonePixbuf.Height()) * ratio))
+
+	return
+}
+
+func (p *playlistPanel) onStandalonePlayClicked() {
+	client.Instance().PlayQueuedAlbum(p.standaloneAlbum)
+	p.closeStandalone()
+}
+
+func (p *playlistPanel) onStandaloneRemoveClicked() {
+	client.Instance().UnqueueAlbum(p.standaloneAlbum)
+	p.closeStandalone()
+}
+
+func (p *playlistPanel) onSelectionRemove() {
+	albums := p.getSelectedAlbums()
+	if len(albums) > 0 {
+		client.Instance().UnqueueAlbums(albums)
+	}
+
+	p.selectButton.SetActive(false)
+}
+
+func (p *playlistPanel) getSelectedAlbums() []*common.PlaylistAlbum {
+	albums := []*common.PlaylistAlbum{}
+	for i := range p.selectionMulti.NItems() {
+		if p.selectionMulti.IsSelected(i) {
+			itemObj := p.selectionMulti.Item(i)
+			if itemObj != nil {
+				itemStr := itemObj.Cast().(*gtk.StringObject)
+				albumID := itemStr.String()
+				album, found := p.albums[albumID]
+				if found {
+					albums = append(albums, album)
+				}
+			}
+		}
+	}
+
+	return albums
+}
+
+func (p *playlistPanel) onSelectionCancel() {
+	p.selectButton.SetActive(false)
+}
+
+func (p *playlistPanel) Toolbar() gtk.Widgetter {
+	return p.toolbar
+}
+
+func (p *playlistPanel) ItemSizeChanged() {
+	p.redraw()
+}
+
+func (p *playlistPanel) redraw() {
+	if len(p.playlist) > 0 {
+		p.SetPlaylist(p.playlist)
+	}
+}
+
+func (p *playlistPanel) SetPlaylist(playlist []*common.PlaylistAlbum) {
+	go p.setPlaylist(playlist)
+}
+
+func (p *playlistPanel) setPlaylist(playlist []*common.PlaylistAlbum) {
+	p.playlist = playlist
+
+	for _, album := range playlist {
+		p.albums[album.ID()] = album
+		if p.coverLoader != nil {
+			p.pixbufs[album.ID()] = p.coverLoader.LoadThumbnail(album.Album)
+		}
+	}
+
+	p.updateGridModel()
+}
+
+func (p *playlistPanel) updateGridModel() {
+	p.updateGrid(p.playlist)
+}
+
+func (p *playlistPanel) updateGrid(albums []*common.PlaylistAlbum) {
+	glib.IdleAdd(func() {
+		n := p.playlistModel.NItems()
+		if n > 0 {
+			p.playlistModel.Splice(0, n, nil)
+		}
+
+		ids := make([]string, 0, len(albums))
+		for _, item := range albums {
+			ids = append(ids, item.ID())
+		}
+
+		if len(ids) > 0 {
+			p.playlistModel.Splice(0, 0, ids)
+		}
+	})
+}
+
+func (p *playlistPanel) SetWidth(width int) {
+	p.resizeStandaloneImage()
+}
+
+func (p *playlistPanel) ClearPlaylist() {
+	client.Instance().ClearPlaylist()
+}
+
+func (p *playlistPanel) HeaderbarStandalone() *albumHeaderbar {
+	return p.headerbarStandalone
+}

internal/gui/serverpanel.go

@@ -0,0 +1,115 @@
+package gui
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type serverPanel struct {
+	*adw.Bin
+
+	toolbar         *gtk.Box
+	statusFile      *gtk.Label
+	statusAudio     *gtk.Label
+	statusBitrate   *gtk.Label
+	statusErrer     *gtk.Label
+	statsArtist     *gtk.Label
+	statsAlbums     *gtk.Label
+	statsSongs      *gtk.Label
+	statsDBPlaytime *gtk.Label
+	statsPlaytime   *gtk.Label
+	statsUptime     *gtk.Label
+	outputDevices   *gtk.ListBox
+
+	outputDeviceChangeCB OutputDeviceChangeCB
+}
+
+type OutputDeviceChangeCB func(device *common.OutputDevice, enable bool)
+
+func newServerPanel() *serverPanel {
+	panel := serverPanel{}
+	panel.loadWidgets()
+
+	return &panel
+}
+
+func (p *serverPanel) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.ServerPanelXML)
+
+	p.Bin = builder.GetObject("McgServerPanel").Cast().(*adw.Bin)
+	p.toolbar = builder.GetObject("toolbar").Cast().(*gtk.Box)
+	p.statusFile = builder.GetObject("status_file").Cast().(*gtk.Label)
+	p.statusAudio = builder.GetObject("status_audio").Cast().(*gtk.Label)
+	p.statusBitrate = builder.GetObject("status_bitrate").Cast().(*gtk.Label)
+	p.statusErrer = builder.GetObject("status_error").Cast().(*gtk.Label)
+	p.statsArtist = builder.GetObject("stats_artists").Cast().(*gtk.Label)
+	p.statsAlbums = builder.GetObject("stats_albums").Cast().(*gtk.Label)
+	p.statsSongs = builder.GetObject("stats_songs").Cast().(*gtk.Label)
+	p.statsDBPlaytime = builder.GetObject("stats_dbplaytime").Cast().(*gtk.Label)
+	p.statsPlaytime = builder.GetObject("stats_playtime").Cast().(*gtk.Label)
+	p.statsUptime = builder.GetObject("stats_uptime").Cast().(*gtk.Label)
+	p.outputDevices = builder.GetObject("output_devices").Cast().(*gtk.ListBox)
+}
+
+func (p *serverPanel) ReceiveOutputDeviceChange(callback OutputDeviceChangeCB) {
+	p.outputDeviceChangeCB = callback
+}
+
+func (p *serverPanel) Toolbar() gtk.Widgetter {
+	return p.toolbar
+}
+
+func (p *serverPanel) Status(file, audio, bitrate, errorMessage string) {
+	p.statusFile.SetText(file)
+	p.statusAudio.SetText(p.formatAudio(audio))
+	p.statusBitrate.SetText(p.formatBitrate(bitrate))
+	p.statusErrer.SetText(errorMessage)
+}
+
+func (p *serverPanel) formatAudio(audio string) string {
+	parts := strings.Split(audio, ":")
+	if len(parts) == 3 {
+		return fmt.Sprintf("%s Hz, %s bit, %s channels", parts[0], parts[1], parts[2])
+	}
+
+	return ""
+}
+
+func (p *serverPanel) formatBitrate(bitrate string) string {
+	if bitrate != "" {
+		return bitrate + " kb/s"
+	}
+
+	return ""
+}
+
+func (p *serverPanel) Statistics(artists, albums, songs, dbplaytime, playtime, uptime string) {
+	p.statsArtist.SetText(artists)
+	p.statsAlbums.SetText(albums)
+	p.statsSongs.SetText(songs)
+	p.statsDBPlaytime.SetText(dbplaytime)
+	p.statsPlaytime.SetText(playtime)
+	p.statsUptime.SetText(uptime)
+}
+
+func (p *serverPanel) OutputDevices(devices []*common.OutputDevice) {
+	p.outputDevices.RemoveAll()
+	for _, device := range devices {
+		deviceButton := gtk.NewCheckButtonWithLabel(device.Name)
+		if device.Enabled {
+			deviceButton.SetActive(true)
+		}
+		deviceButton.ConnectToggled(func() {
+			if p.outputDeviceChangeCB != nil {
+				p.outputDeviceChangeCB(device, deviceButton.Active())
+			}
+		})
+
+		p.outputDevices.Insert(deviceButton, -1)
+	}
+}

internal/gui/shortcutsdialog.go

@@ -0,0 +1,23 @@
+package gui
+
+import (
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+)
+
+type shortcutsDialog struct {
+	*gtk.ShortcutsWindow
+}
+
+func newShortcutsDialog() *shortcutsDialog {
+	dialog := shortcutsDialog{}
+	dialog.loadWidgets()
+
+	return &dialog
+}
+
+func (d *shortcutsDialog) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.ShortcutsDialogXML)
+
+	d.ShortcutsWindow = builder.GetObject("McgShortcutsDialog").Cast().(*gtk.ShortcutsWindow)
+}

internal/gui/window.go

@@ -0,0 +1,454 @@
+package gui
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gdk/v4"
+	"github.com/diamondburned/gotk4/pkg/gio/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+	"suruatoel.xyz/mcg/internal/i18n"
+)
+
+type Panel interface {
+	Toolbar() gtk.Widgetter
+}
+
+type GridPanel interface {
+	HeaderbarStandalone() *albumHeaderbar
+}
+
+type mainWindow struct {
+	*adw.ApplicationWindow
+
+	toggleFullscreenAction *gio.SimpleAction
+	playAaction            *gio.SimpleAction
+	panelAction            *gio.SimpleAction
+	clearPlaylistAction    *gio.SimpleAction
+	searchLibraryAction    *gio.SimpleAction
+
+	toolbarView         *adw.ToolbarView
+	headerBar           *adw.HeaderBar
+	connectButton       *gtk.Switch
+	connectButtonActive bool
+	playButton          *gtk.ToggleButton
+	playButtonActive    bool
+	volumeButton        *gtk.VolumeButton
+	settingVolume       bool
+	toolbarStack        *gtk.Stack
+	infoToast           *adw.ToastOverlay
+	contentStack        *gtk.Stack
+	connectionPanel     *connectionPanel
+	panelStack          *adw.ViewStack
+	serverPanel         *serverPanel
+	coverPanel          *coverPanel
+	playlistPanel       *playlistPanel
+	libraryPanel        *libraryPanel
+	resizeHelper        *gtk.DrawingArea
+
+	panels       map[string]Panel
+	currentWidth int
+	coverLoader  *CoverLoader
+}
+
+func newMainWindow(app *gtk.Application, config Configuration) *mainWindow {
+	window := mainWindow{
+		panels: make(map[string]Panel),
+	}
+	window.loadWidgets(app, config)
+	window.connectSignals()
+	window.registerActions()
+	window.SetHelpOverlay(newShortcutsDialog().ShortcutsWindow)
+
+	return &window
+}
+
+func (w *mainWindow) loadWidgets(app *gtk.Application, config Configuration) {
+	builder := gtk.NewBuilderFromString(data.WindowXML)
+	w.ApplicationWindow = builder.GetObject("McgAppWindow").Cast().(*adw.ApplicationWindow)
+	w.ApplicationWindow.SetApplication(app)
+
+	w.toolbarView = builder.GetObject("toolbar_view").Cast().(*adw.ToolbarView)
+	w.headerBar = builder.GetObject("headerbar").Cast().(*adw.HeaderBar)
+
+	w.connectButton = builder.GetObject("headerbar_button_connect").Cast().(*gtk.Switch)
+	w.connectButtonActive = true
+
+	w.playButton = builder.GetObject("headerbar_button_playpause").Cast().(*gtk.ToggleButton)
+	w.playButtonActive = true
+
+	w.volumeButton = builder.GetObject("headerbar_button_volume").Cast().(*gtk.VolumeButton)
+	w.volumeButton.ConnectValueChanged(w.OnVolumeChanged)
+
+	w.toolbarStack = builder.GetObject("toolbar_stack").Cast().(*gtk.Stack)
+
+	w.infoToast = builder.GetObject("info_toast").Cast().(*adw.ToastOverlay)
+
+	w.contentStack = builder.GetObject("content_stack").Cast().(*gtk.Stack)
+
+	w.connectionPanel = newConnectionPanel(config)
+	w.contentStack.AddChild(w.connectionPanel)
+	w.contentStack.SetVisibleChild(w.connectionPanel)
+
+	// Server panel
+	w.serverPanel = newServerPanel()
+	w.panels["server"] = w.serverPanel
+	w.serverPanel.ReceiveOutputDeviceChange(w.OnServerPanelOutputDeviceChange)
+
+	// Cover panel
+	w.coverPanel = newCoverPanel()
+	w.panels["cover"] = w.coverPanel
+
+	// Playlist panel
+	w.playlistPanel = newPlaylistPanel()
+	w.panels["playlist"] = w.playlistPanel
+
+	// Library panel
+	w.libraryPanel = newLibraryPanel(config)
+	w.panels["library"] = w.serverPanel
+
+	// Panel stack
+	w.panelStack = builder.GetObject("panel_stack").Cast().(*adw.ViewStack)
+	w.panelStack.AddTitledWithIcon(w.serverPanel, "server", i18n.T("Server"), "network-wired-symbolic")
+	w.panelStack.AddTitledWithIcon(w.coverPanel, "cover", i18n.T("Cover"), "image-x-generic-symbolic")
+	w.panelStack.AddTitledWithIcon(w.playlistPanel, "playlist", i18n.T("Playlist"), "view-list-symbolic")
+	w.panelStack.AddTitledWithIcon(w.libraryPanel, "library", i18n.T("Library"), "emblem-music-symbolic")
+	if _, found := w.panels[config.Panel]; found {
+		w.panelStack.SetVisibleChildName(config.Panel)
+	} else {
+		log.Println("configured initial panel name is unknown:", config.Panel)
+	}
+
+	// Toolbar stack
+	w.toolbarStack.AddNamed(w.serverPanel.Toolbar(), "server")
+	w.toolbarStack.AddNamed(w.coverPanel.Toolbar(), "cover")
+	w.toolbarStack.AddNamed(w.playlistPanel.Toolbar(), "playlist")
+	w.toolbarStack.AddNamed(w.libraryPanel.Toolbar(), "library")
+	w.toolbarStack.SetVisibleChildName(config.Panel)
+
+	w.resizeHelper = builder.GetObject("resize_helper").Cast().(*gtk.DrawingArea)
+}
+
+func (w *mainWindow) connectSignals() {
+	w.connectButton.Connect("notify::active", func() {
+		w.connect()
+	})
+	w.connectButton.ConnectStateSet(w.OnConnectStateSet)
+
+	w.playButton.ConnectToggled(w.OnPlayPauseToggled)
+
+	w.panelStack.Connect("notify::visible-child", w.OnPanelStackSwitched)
+	w.resizeHelper.ConnectResize(w.OnWindowResize)
+
+	w.coverPanel.ConnectFullscreen(w.OnCoverPanelFullscreen)
+	w.Connect("notify::fullscreened", w.OnWindowFullscreen)
+
+	w.playlistPanel.ConnectStandalone(w.OnPlaylistPanelStandalone)
+
+	w.libraryPanel.ConnectItemSizeChanged(w.onLibraryPanelItemSizeChanged)
+	w.libraryPanel.ConnectStandalone(w.OnLibraryPanelStandalone)
+
+	clientInstance := client.Instance()
+	clientInstance.ReceiveError(w.OnClientError)
+	clientInstance.RegisterConnection(w.OnClientConnection)
+	clientInstance.ReceiveStatus(w.OnClientStatus)
+	clientInstance.ReceiveStatistics(w.OnClientStatistics)
+	clientInstance.ReceiveOutputDevices(w.OnClientOutputDevces)
+	clientInstance.ReceivePlaylist(w.OnClientPlaylist)
+	clientInstance.ReceiveAlbums(w.OnClientAlbums)
+	clientInstance.ReceiveAlbumart(w.OnClientAlbumart)
+}
+
+func (w *mainWindow) registerActions() {
+	connectAction := gio.NewSimpleAction("connect", nil)
+	connectAction.ConnectActivate(func(_ *glib.Variant) {
+		w.connect()
+	})
+	w.AddAction(connectAction)
+
+	w.playAaction = gio.NewSimpleAction("play", nil)
+	w.playAaction.SetEnabled(false)
+	w.playAaction.ConnectActivate(func(_ *glib.Variant) {
+		w.OnPlayPauseToggled()
+	})
+	w.AddAction(w.playAaction)
+
+	w.clearPlaylistAction = gio.NewSimpleAction("clear-playlist", nil)
+	w.clearPlaylistAction.SetEnabled(false)
+	w.clearPlaylistAction.ConnectActivate(func(_ *glib.Variant) {
+		w.playlistPanel.ClearPlaylist()
+	})
+	w.AddAction(w.clearPlaylistAction)
+
+	panelVariant := glib.NewVariantString("server")
+	w.panelAction = gio.NewSimpleActionStateful("panel", panelVariant.Type(), panelVariant)
+	w.panelAction.SetEnabled(false)
+	w.panelAction.ConnectActivate(func(value *glib.Variant) {
+		panelName := value.String()
+		w.panelStack.SetVisibleChildName(panelName)
+	})
+	w.AddAction(w.panelAction)
+
+	w.toggleFullscreenAction = gio.NewSimpleAction("toggle-fullscreen", nil)
+	w.toggleFullscreenAction.SetEnabled(false)
+	w.toggleFullscreenAction.ConnectActivate(func(_ *glib.Variant) {
+		w.Fullscreen()
+	})
+	w.AddAction(w.toggleFullscreenAction)
+
+	w.searchLibraryAction = gio.NewSimpleAction("search-library", nil)
+	w.searchLibraryAction.SetEnabled(false)
+	w.searchLibraryAction.ConnectActivate(func(_ *glib.Variant) {
+		w.panelStack.SetVisibleChild(w.libraryPanel)
+		w.libraryPanel.ShowSearch()
+	})
+	w.AddAction(w.searchLibraryAction)
+}
+
+func (w *mainWindow) OnPanelStackSwitched() {
+	w.setVisibleToolbar()
+}
+
+func (w *mainWindow) setVisibleToolbar() {
+	name := w.panelStack.VisibleChildName()
+	w.toolbarStack.SetVisibleChildName(name)
+}
+
+func (w *mainWindow) OnWindowFullscreen() {
+	w.reactToFullscreen()
+}
+
+func (w *mainWindow) reactToFullscreen() {
+	var cursor *gdk.Cursor
+	if w.IsFullscreen() {
+		w.panelStack.SetVisibleChild(w.coverPanel)
+		w.headerBar.SetVisible(false)
+		w.coverPanel.Fullscreen(true)
+		cursor = gdk.NewCursorFromName("none", nil)
+	} else {
+		w.headerBar.SetVisible(true)
+		w.coverPanel.Fullscreen(false)
+		cursor = gdk.NewCursorFromName("default", nil)
+	}
+
+	w.SetCursor(cursor)
+}
+
+func (w *mainWindow) OnCoverPanelFullscreen() {
+	if w.IsFullscreen() {
+		w.Unfullscreen()
+	} else {
+		w.Fullscreen()
+	}
+}
+
+func (w *mainWindow) OnPlaylistPanelStandalone(open bool) {
+	w.onPanelStandalone(w.playlistPanel, open)
+}
+
+func (w *mainWindow) onLibraryPanelItemSizeChanged(itemSize int) {
+	w.coverLoader.SetSize(itemSize)
+	w.playlistPanel.ItemSizeChanged()
+}
+
+func (w *mainWindow) OnLibraryPanelStandalone(open bool) {
+	w.onPanelStandalone(w.libraryPanel, open)
+}
+
+func (w *mainWindow) onPanelStandalone(panel GridPanel, open bool) {
+	if open {
+		w.toolbarView.AddTopBar(panel.HeaderbarStandalone())
+		w.toolbarView.Remove(w.headerBar)
+	} else {
+		w.toolbarView.AddTopBar(w.headerBar)
+		w.toolbarView.Remove(panel.HeaderbarStandalone())
+	}
+}
+
+func (w *mainWindow) connect() {
+	if !w.connectButtonActive {
+		return
+	}
+
+	if client.Instance().IsConnected() {
+		w.libraryPanel.Wait()
+		client.Instance().Disconnect()
+	} else {
+		client.Instance().Connect(w.connectionPanel.ConnectionDetails())
+	}
+}
+
+func (w *mainWindow) OnClientConnection(connected bool) {
+	glib.IdleAdd(func() {
+		w.connectButtonActive = false
+		w.connectButton.SetActive(connected)
+		w.connectButton.SetState(connected)
+		w.connectButtonActive = true
+
+		w.playButton.SetSensitive(connected)
+		w.volumeButton.SetSensitive(connected)
+		w.playAaction.SetEnabled(connected)
+		w.panelAction.SetEnabled(connected)
+		if connected {
+			w.contentStack.SetVisibleChild(w.panelStack)
+		} else {
+			w.contentStack.SetVisibleChild(w.connectionPanel)
+		}
+
+		w.clearPlaylistAction.SetEnabled(connected)
+		w.searchLibraryAction.SetEnabled(connected)
+	})
+
+	host, _, _ := w.connectionPanel.ConnectionDetails()
+	w.coverLoader = NewCoverLoader(host)
+	w.playlistPanel.setCoverLoader(w.coverLoader)
+	w.libraryPanel.setCoverLoader(w.coverLoader)
+}
+
+func (w *mainWindow) SetConfigError(err error) {
+	glib.IdleAdd(func() {
+		w.infoToast.AddToast(adw.NewToast(fmt.Sprintf("Loading the configuration has failed: %s", err.Error())))
+	})
+}
+
+func (w *mainWindow) UpdateConfig(config *Configuration) {
+	config.Panel = w.panelStack.VisibleChildName()
+
+	w.connectionPanel.UpdateConfig(config)
+	w.libraryPanel.UpdateConfig(config)
+}
+
+func (w *mainWindow) OnClientError(message string) {
+	glib.IdleAdd(func() {
+		w.infoToast.AddToast(adw.NewToast(message))
+	})
+}
+
+func (w *mainWindow) OnClientStatus(state string, album *common.PlaylistAlbum, pos uint64, time uint64, volume int64, file string, audio string, bitrate string, errorMessage string) {
+	// Album
+	glib.IdleAdd(func() {
+		w.coverPanel.SetAlbum(state, album)
+	})
+	w.toggleFullscreenAction.SetEnabled(album != nil)
+
+	// Fullscreen
+	if w.IsFullscreen() && album == nil {
+		w.Unfullscreen()
+	}
+
+	// State
+	if state == "play" {
+		glib.IdleAdd(func() {
+			w.setPlayPause(true)
+		})
+		glib.IdleAdd(func() {
+			w.coverPanel.SetPlay(pos, time)
+		})
+	} else if state == "pause" || state == "stop" {
+		glib.IdleAdd(func() {
+			w.setPlayPause(false)
+		})
+		w.coverPanel.SetPause()
+	}
+	// Volume
+	glib.IdleAdd(func() {
+		w.setVolume(volume)
+	})
+
+	glib.IdleAdd(func() {
+		w.serverPanel.Status(file, audio, bitrate, errorMessage)
+	})
+}
+
+func (w *mainWindow) OnClientStatistics(artists, albums, songs, dbplaytime, playtime, uptime string) {
+	glib.IdleAdd(func() {
+		w.serverPanel.Statistics(artists, albums, songs, dbplaytime, playtime, uptime)
+	})
+}
+
+func (w *mainWindow) OnClientOutputDevces(devices []*common.OutputDevice) {
+	glib.IdleAdd(func() {
+		w.serverPanel.OutputDevices(devices)
+	})
+}
+
+func (w *mainWindow) OnClientPlaylist(playlist []*common.PlaylistAlbum) {
+	w.playlistPanel.SetPlaylist(playlist)
+}
+
+func (w *mainWindow) OnClientAlbums(albums map[string]*common.Album) {
+	w.libraryPanel.SetAlbums(albums)
+}
+
+func (w *mainWindow) OnClientAlbumart(album *common.Album, albumart []byte) {
+	w.coverPanel.SetAlbumart(album, albumart)
+	w.playlistPanel.SetAlbumart(album, albumart)
+	w.libraryPanel.SetAlbumart(album, albumart)
+}
+
+func (w *mainWindow) OnConnectStateSet(state bool) bool {
+	return true
+}
+
+func (w *mainWindow) OnPlayPauseToggled() {
+	if w.playButtonActive {
+		client.Instance().PlayPause()
+	}
+}
+
+func (w *mainWindow) OnVolumeChanged(value float64) {
+	if !w.settingVolume {
+		client.Instance().SetVolume(int(value * 100))
+	}
+}
+
+func (w *mainWindow) setPlayPause(play bool) {
+	w.playButtonActive = false
+	w.playButton.SetActive(play)
+	w.playButtonActive = true
+}
+
+func (w *mainWindow) setVolume(volume int64) {
+	if volume >= 0 {
+		w.volumeButton.SetVisible(true)
+		w.settingVolume = true
+		w.volumeButton.SetValue(float64(volume) / 100.0)
+		w.settingVolume = false
+	} else {
+		w.volumeButton.SetVisible(false)
+	}
+}
+
+func (w *mainWindow) OnServerPanelOutputDeviceChange(device *common.OutputDevice, enable bool) {
+	client.Instance().SetOutputDeviceState(device, enable)
+}
+
+func (w *mainWindow) OnWindowResize(width int, _ int) {
+	if !w.hasWidthChanged(width) {
+		return
+	}
+	w.setWidth(width)
+
+	if width > 0 {
+		w.updateUIWidth()
+	}
+}
+
+func (w *mainWindow) hasWidthChanged(width int) bool {
+	return width != w.currentWidth
+}
+
+func (w *mainWindow) setWidth(width int) {
+	w.currentWidth = width
+}
+
+func (w *mainWindow) updateUIWidth() {
+	w.coverPanel.SetWidth(w.currentWidth)
+	w.playlistPanel.SetWidth(w.currentWidth)
+	w.libraryPanel.SetWidth(w.currentWidth)
+}

main.go

@@ -1,9 +1,18 @@
 package main
 
 import (
+	"os"
+
+	"suruatoel.xyz/mcg/internal/gui"
 	"suruatoel.xyz/mcg/internal/i18n"
 )
 
 func main() {
 	i18n.Init("mcg", "locale")
+
+	app := gui.NewApplication()
+	exitCode := app.Run(os.Args)
+	if exitCode > 0 {
+		os.Exit(exitCode)
+	}
 }