set wallpaper

modules/home/wallpaper.nix

@@ -1,14 +0,0 @@
-{ pkgs, lib, ... }:
-let
-  walls = pkgs.fetchFromGitHub {
-    owner = "orangci";
-    repo  = "walls-catppuccin-mocha";
-    rev   = "40912e6418737e93b59a38bcf189270cbf26656d";
-    hash  = "sha256-1QR3J+wgLVNjucPSVELv0FicNt+jM2KPLU5ubBfxjHI=";   # nix-shell -p nix-prefetch-github --run 'nix-prefetch-github orangci walls-catppuccin-mocha --rev 40912e6418737e93b59a38bcf189270cbf26656d'
-  };
-in {
-  home.file."wallpapers" = {
-    source = walls;
-    recursive = true;
-  };
-}

modules/home/wallpaper/default.nix

@@ -0,0 +1,70 @@
+{ pkgs, lib, ... }:
+let
+  walls = pkgs.fetchFromGitHub {
+    owner = "orangci";
+    repo  = "walls-catppuccin-mocha";
+    rev   = "40912e6418737e93b59a38bcf189270cbf26656d";
+    hash  = "sha256-1QR3J+wgLVNjucPSVELv0FicNt+jM2KPLU5ubBfxjHI=";
+  };
+in {
+  home.file."wallpapers" = {
+    source = walls;
+    recursive = true;
+  };
+
+  home.file.".local/bin/set-wallpaper.sh" = {
+    source = ./set-wallpaper.sh;
+    executable = true;
+  };
+
+  home.packages = with pkgs; [
+    swww
+    bash
+    findutils
+    coreutils
+  ];
+
+  systemd.user.services.swww = {
+    Unit = {
+      Description = "swww daemon";
+      After = [ "graphical-session.target" ];
+    };
+    Service = {
+      ExecStart = "${pkgs.swww}/bin/swww-daemon";
+      Restart = "on-failure";
+    };
+    Install = {
+      WantedBy = [ "graphical-session.target" ];
+    };
+  };
+
+  systemd.user.services."wallpaper-rotate" = {
+    Unit = {
+      Description = "Rotate wallpaper via swww";
+      After = [ "swww.service" "graphical-session.target" ];
+      Wants = [ "swww.service" ];
+    };
+    Service = {
+      Type = "oneshot";
+      ExecStart = "${pkgs.bash}/bin/bash -lc $HOME/.local/bin/set-wallpaper.sh";
+    };
+    Install = {
+      WantedBy = [ "default.target" ];
+    };
+  };
+
+  systemd.user.timers."wallpaper-rotate" = {
+    Unit = {
+      Description = "Change wallpaper every 1 minute";
+    };
+    Timer = {
+      OnBootSec = "30s";
+      OnUnitActiveSec = "1min";
+      Unit = "wallpaper-rotate.service";
+      Persistent = true;
+    };
+    Install = {
+      WantedBy = [ "timers.target" ];
+    };
+  };
+}

modules/home/wallpaper/set-wallpaper.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# set-wallpaper.sh
+set -euo pipefail
+
+WALLS="${HOME}/wallpapers"
+
+# Pick up wallpaper（jpg/jpeg/png/webp）
+mapfile -t files < <(find "$WALLS" -type f \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' -o -iname '*.webp' \))
+[[ ${#files[@]} -gt 0 ]] || exit 0
+
+pick="${files[RANDOM % ${#files[@]}]}"
+
+exec swww img "$pick" --transition-type any --transition-step 90 --transition-fps 60