#!/bin/bash

# File: convert-to-webp.sh
# Version: 1.1
# Purpose: Convert JPG/PNG to square WebP (centered or top-aligned)
# Usage:
#   ./convert-to-webp.sh image1.jpg image2.png ...
#   ./convert-to-webp.sh --top image1.jpg image2.png ...

set -e

# Default to center crop
CROP_MODE="center"

# Check for --top flag
if [[ "$1" == "--top" ]]; then
  CROP_MODE="top"
  shift
fi

if [ "$#" -eq 0 ]; then
  echo "Usage:"
  echo "  $0 image1.jpg image2.png ..."
  echo "  $0 --top image1.jpg image2.png ..."
  echo
  echo "Use --top to crop from bottom up (better for portraits)."
  exit 1
fi

for input in "$@"; do
  if [[ ! -f "$input" ]]; then
    echo "Skipping '$input': not a file"
    continue
  fi

  ext="${input##*.}"
  ext_lc="$(echo "$ext" | tr '[:upper:]' '[:lower:]')"
  if [[ "$ext_lc" != "jpg" && "$ext_lc" != "jpeg" && "$ext_lc" != "png" ]]; then
    echo "Skipping '$input': unsupported format"
    continue
  fi

  base_name="$(basename "$input" .${ext})"
  output="${base_name}.webp"

  dims=$(identify -format "%w %h" "$input")
  width=$(echo "$dims" | cut -d' ' -f1)
  height=$(echo "$dims" | cut -d' ' -f2)

  if [ "$width" -gt "$height" ]; then
    # Landscape
    offset_x=$(( (width - height) / 2 ))
    offset_y=0
    crop="${height}x${height}+${offset_x}+${offset_y}"
  else
    # Portrait or square
    offset_x=0
    if [[ "$CROP_MODE" == "top" ]]; then
      offset_y=0
    else
      offset_y=$(( (height - width) / 2 ))
    fi
    crop="${width}x${width}+${offset_x}+${offset_y}"
  fi

  echo "Converting '$input' to '$output' (crop: $crop, mode: $CROP_MODE)..."
  convert "$input" -crop "$crop" +repage -quality 90 "$output"
done

echo "All done."