Convert change_wallpaper.sh using nix writeShellApplication

hosts/totsugeki/desktop/scripts/change-wallpaper.nix

@@ -0,0 +1,81 @@
+{ pkgs }:
+
+pkgs.writeShellApplication {
+  name = "change-wallpaper";
+  runtimeInputs = with pkgs; [ dunst rofi swww ];
+  text = ''
+    shopt -s nullglob
+
+    WALLPAPER_PATH="$HOME/.local/share/wallpapers"
+    WALLPAPERS=("$WALLPAPER_PATH"/*)
+
+    if [ ! -f "$WALLPAPER_PATH/.current_path" ]; then
+        # Current wallpaper file does not exist, create it
+        echo "''${WALLPAPERS[0]}" > "$WALLPAPER_PATH/.current_path"
+    fi
+
+    CURRENT_WALLPAPER=$(cat "$WALLPAPER_PATH/.current_path")
+    CURRENT_WP_INDEX=-1
+    # Get the current wallpaper's index
+    for index in "''${!WALLPAPERS[@]}"; do
+        if [ "''${WALLPAPERS[$index]}" = "$CURRENT_WALLPAPER" ]; then
+            CURRENT_WP_INDEX=$index
+        fi
+    done
+
+    if [ "$CURRENT_WP_INDEX" -eq -1 ]; then
+        CURRENT_WP_INDEX=0
+    fi
+
+    if [ "$1" = "previous" ]; then
+        WALLPAPER="''${WALLPAPERS[$CURRENT_WP_INDEX - 1]}"
+        TRANSITION_ANGLE=300
+    elif [ "$1" = "next" ]; then
+        NEXT_INDEX=$((CURRENT_WP_INDEX + 1))
+        if [ "$NEXT_INDEX" = "''${#WALLPAPERS[@]}" ]; then
+            NEXT_INDEX=0
+        fi
+        WALLPAPER=''${WALLPAPERS[$NEXT_INDEX]}
+        TRANSITION_ANGLE=120
+    elif [ "$1" = "open-menu" ]; then
+        INPUT=""
+        for index in "''${!WALLPAPERS[@]}"; do
+            if [ "$index" = "$CURRENT_WP_INDEX" ]; then
+                continue
+            fi
+            _WALLPAPER=''${WALLPAPERS[$index]}
+            _WALLPAPER_NAME=$(basename "$_WALLPAPER")
+            INPUT+="$_WALLPAPER_NAME\0icon\x1f$_WALLPAPER"
+            if [ ! $((index + 1)) -eq ''${#WALLPAPERS[@]} ]; then
+                INPUT+=$'\n'
+            fi
+        done
+        if ! WALLPAPER=$(echo -en "$INPUT" | rofi -dmenu -mesg "Cambiar fondo de pantalla" -p "" -i -theme ~/.config/rofi/wallpaper_selector.rasi); then
+            exit 1
+        fi
+        WALLPAPER="$WALLPAPER_PATH/$WALLPAPER"
+        TRANSITION_ANGLE=270
+    else
+        echo "Unknown first argument: $1"
+        exit 1
+    fi
+
+    if [ -z "$WALLPAPER" ]; then
+        exit 1
+    fi
+
+    WALLPAPER_NAME=$(basename "$WALLPAPER")
+    echo "Setting wallpaper to $WALLPAPER"
+    echo "$WALLPAPER" > "$WALLPAPER_PATH/.current_path"
+    ln -sf "$WALLPAPER" "$WALLPAPER_PATH/.current_image"
+    dunstify -i "$WALLPAPER" -t 2800 "Cambiando fondo de pantalla" "Cambiando a $WALLPAPER_NAME"
+    swww img\
+        --transition-type wipe\
+        --transition-angle $TRANSITION_ANGLE\
+        --transition-step 90\
+        --transition-duration 1\
+        --transition-fps 165\
+        "$WALLPAPER"
+
+  '';
+}