#!/bin/bash

DIR="./images" # 対象ディレクトリパス(要変更)
JPEG_CWEBP_OPTS="-q 75 -m 4" # Jpeg向け非可逆cwebpオプション
PNG_CWEBP_OPTS="-lossless" # PNG向け可逆cwebpオプション
CWEBP="/usr/local/bin/cwebp" # cwebpコマンドの場所

cd $(dirname $0)
shopt -s nocasematch

find $DIR -type f -regextype posix-extended -iregex ".*\.(jpe?g|png)$" -print0 | \
while IFS= read -r -d '' SRC; do
  WEBP="$SRC.webp"
  if [[ ! -e $WEBP || $SRC -nt $WEBP ]]; then
    if [[ $SRC =~ \.jpe?g$ ]]; then
      echo "Convert to lossy WebP: $SRC"
      "$CWEBP" $JPEG_CWEBP_OPTS "$SRC" -o "$WEBP"
    elif [[ $SRC =~ \.png$ ]]; then
      echo "Convert to lossless WebP: $SRC"
      "$CWEBP" $PNG_CWEBP_OPTS "$SRC" -o "$WEBP"
    fi
  fi
done

<IfModule mod_setenvif.c>
  SetEnvIf Request_URI "\.(jpe?g|png)$" _image_request
</IfModule>

<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteCond %{HTTP_ACCEPT} image/webp
  RewriteCond %{SCRIPT_FILENAME}.webp -f
  RewriteRule .(jpe?g|png)$ %{SCRIPT_FILENAME}.webp [T=image/webp]
</IfModule>

<IfModule mod_headers.c>
  Header append Vary Accept env=_image_request
</IfModule>

<IfModule mod_mime.c>
  AddType image/webp .webp
</IfModule>