Full rewrite

.github/scripts/compress-images.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+# Losslessly compress wallpapers before they are committed, so the repo
+# doesn't grow larger than it needs to. Only files staged in this commit
+# are touched, to keep the hook fast.
+
+set -uo pipefail
+
+wallpapers_dir="wallpapers"
+changed=0
+
+if [[ ! -d "$wallpapers_dir" ]]; then
+  exit 0
+fi
+
+if ! command -v oxipng >/dev/null 2>&1; then
+  echo "❌ oxipng is required but was not found in PATH"
+  exit 1
+fi
+if ! command -v gifsicle >/dev/null 2>&1; then
+  echo "❌ gifsicle is required but was not found in PATH"
+  exit 1
+fi
+
+mapfile -t staged < <(git diff --cached --name-only --diff-filter=ACM -- "$wallpapers_dir")
+
+for file in "${staged[@]}"; do
+  [[ -f "$file" ]] || continue
+  ext="${file##*.}"
+
+  before=$(stat -c%s "$file")
+
+  case "$ext" in
+    png)
+      oxipng -o max --strip safe -q "$file" >/dev/null
+      ;;
+    gif)
+      gifsicle -O3 --batch "$file"
+      ;;
+    *)
+      continue
+      ;;
+  esac
+
+  after=$(stat -c%s "$file")
+  if [[ "$after" -ne "$before" ]]; then
+    echo "Compressed $file ($before -> $after bytes)"
+    git add "$file"
+    changed=1
+  fi
+done
+
+if [[ "$changed" -eq 1 ]]; then
+  echo "Image(s) were compressed and re-staged, please commit again."
+  exit 1
+fi
+
+exit 0