#!/bin/bash

# Directory to start from (default is current directory if none given)
DIR="${1:-.}"

# Optional prefix filter (second argument)
PREFIX="${2:-}"

# JPEG/WEBP compression quality (1–100, lower = more compression)
QUALITY=85

# Target max size
MAXSIZE="1920x1040"

# Recursively find images and compress them
find "$DIR" -type f \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' -o -iname '*.webp' \) | while read -r FILE; do
    BASENAME=$(basename "$FILE")
    EXT="${FILE##*.}"
    EXT_LOWER=$(echo "$EXT" | tr '[:upper:]' '[:lower:]')

    # Skip if prefix is set and filename doesn’t start with it
    if [ -n "$PREFIX" ] && [[ "$BASENAME" != "$PREFIX"* ]]; then
        continue
    fi

    echo "Processing: $FILE"

    TMPFILE="$(mktemp --suffix=".$EXT_LOWER")"

    case "$EXT_LOWER" in
        jpg|jpeg)
            convert "$FILE" -resize "$MAXSIZE"\> -strip -interlace Plane -quality $QUALITY "$TMPFILE"
            ;;
        png|webp)
            convert "$FILE" -resize "$MAXSIZE"\> -strip -quality $QUALITY "$TMPFILE"
            ;;
    esac

    mv "$TMPFILE" "$FILE"
done