chbg: full argparse support

merged from `chbg-slide`.

bin/chbg

@@ -1,34 +1,137 @@
 #!/bin/bash
-# to change wallpapers both niri workspace and niri tab view
-[ -z "$1" ] && {
-    echo "Usage: ${0##*/} <image-file>"
-    exit 1
-}
-fsize=$(magick identify -format "%w %h" -- "$1" 2>/dev/null) || {
-    echo "ERROR: unable to identify. is it an EXISTING ACCESSIBLE IMAGE file?"
-    exit 1
-}
+set -euo pipefail
 
+THIS_COMMAND=$(basename "$0")
+IMG_MAGICK="magick"
 WP_DIR="${XDG_DATA_HOME:-$HOME/.local/share}"
-finput=$1
 
-read -r fw fh <<< "$fsize"
-(( fw > 3840 && fh > 2160 )) && {
+usage() {
+  cat << EOF
+Usage: $THIS_COMMAND [-d output_path] image1 image2 ...
+Options:
+  -d, --dir OUTPUT_PATH   Directory to store chosen image. (default: $WP_DIR)
+  -h, --help              Show this help message and exit.
+Notes:
+  - Images can be provided as arguments or via stdin. If both are used, they are combined.
+  - Web URLs are also supported (via 'curl' or 'wget' downloading).
+  - If multiple images are provided, one will be randomly picked each time the script is executed.
+EOF
+  exit 1
+}
+
+# showing help shouldn't require any dependencies.
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -d|--dir)
+      if [[ $# -lt 2 ]]; then echo "Missing argument for $1"; usage; fi
+      WP_DIR="$2"; shift 2 ;;
+    -h|--help)
+      usage ;;
+    --)
+      shift; break ;;
+    -*)
+      echo "Unknown option: $1"; usage ;;
+    *)
+      break ;;
+  esac
+done
+
+if ! command -v swww >/dev/null 2>&1; then
+  echo "!) 'swww' command not found. Unable to comply." >&2
+  exit 2
+fi
+
+if command -v magick >/dev/null 2>&1; then
+  IMG_MAGICK="magick"
+elif command -v convert >/dev/null 2>&1; then
+  IMG_MAGICK="convert"
+else
+  echo "!) 'magick' or 'convert' command not found. Image processing unavailable." >&2
+  exit 2
+fi
+
+set_wallpaper() {
+  fsize=$($IMG_MAGICK identify -format "%w %h" -- "$1" 2>/dev/null) || {
+    echo "Invalid image file." >&2
+    exit 10
+  }
+  finput=$1
+
+  read -r fw fh <<< "$fsize"
+  (( fw > 3840 && fh > 2160 )) && {
     finput=$(mktemp "${TMPDIR:-/tmp}/chbg.XXXXXXXX.webp")
     trap 'rm -f "$finput"' EXIT
-    echo "WARNING: image too large, resizing ..."
+    echo "-> image too large, resizing ..."
     # echo "DEBUG: resized image at $finput"
-    magick "$1" -resize "3840x2160^" \
+    $IMG_MAGICK "$1" -resize "3840x2160^" \
       -quality 90 \
       -define webp:method=6 \
       -define webp:alpha-quality=100 "$finput"
+  }
+
+  echo -n "-> making blurred version of '${1##*/}' ... "
+  cp $finput $WP_DIR/.wallpaper
+  $IMG_MAGICK $WP_DIR/.wallpaper -filter Gaussian -blur 0x30 $WP_DIR/.wallpaper_blur
+  echo "Done."
+
+  swww img $WP_DIR/.wallpaper
+  swww img $WP_DIR/.wallpaper_blur --namespace blur
 }
 
-echo -n "making blurred version of ${1##*/} ... "
-mkdir -p $WP_DIR
-cp $finput $WP_DIR/.wallpaper
-magick $WP_DIR/.wallpaper -filter Gaussian -blur 0x30 $WP_DIR/.wallpaper_blur
-echo "Done."
+imagepool=()
+lastresult=""
 
-swww img $WP_DIR/.wallpaper
-swww img $WP_DIR/.wallpaper_blur --namespace blur 
+# Read from stdin if data is available
+if [ ! -t 0 ]; then
+  while IFS= read -r line; do
+    imagepool+=("$line")
+  done
+fi
+
+# Read from positional arguments
+for arg in "$@"; do
+  imagepool+=("$arg")
+done
+
+if [ ${#imagepool[@]} -eq 0 ]; then
+  echo "No images provided." >&2
+  exit 1
+fi
+
+mkdir -p -- "$WP_DIR" "/tmp/$USER"
+
+if [ -f "/tmp/$USER/chbg.last-slide.log" ]; then
+  lastresult=$(cat "/tmp/$USER/chbg.last-slide.log")
+fi
+
+# Select a random image from the pool and set it as wallpaper
+while : ; do
+  randomimage="${imagepool[RANDOM % ${#imagepool[@]}]}"
+  if [[ "$randomimage" == "http://"* || "$randomimage" == "https://"* ]]; then
+    break
+  fi
+
+  if [ "$randomimage" != "$lastresult" ] || [ ${#imagepool[@]} -eq 1 ]; then
+    echo "$randomimage" > "/tmp/$USER/chbg.last-slide.log"
+    break
+  fi
+done
+
+echo "Selected: $randomimage"
+
+if [ -f "$randomimage" ]; then
+  set_wallpaper "$randomimage"
+  exit 0
+fi
+
+tmpfile=$(mktemp)
+trap 'rm -f "$tmpfile"' EXIT
+if command -v curl >/dev/null 2>&1; then
+  curl -sSL "$randomimage" -o "$tmpfile"
+elif command -v wget >/dev/null 2>&1; then
+  wget -qO "$tmpfile" "$randomimage"
+else
+  echo "!) Unable to fetch image without 'curl' or 'wget'." >&2
+  exit 2
+fi
+set_wallpaper "$tmpfile"