#!/usr/bin/env bash
set -euo pipefail

# Minimal PWA icon generator (no manifest/html)
# Outputs: icon-192.png, icon-512.png, icon-maskable-192.png, icon-maskable-512.png,
#          apple-touch-icon.png (180x180), favicon.ico (16/32/48)

# Detect ImageMagick binary
if command -v magick >/dev/null 2>&1; then
  IM="magick"
elif command -v convert >/dev/null 2>&1; then
  IM="convert"
else
  echo "Error: ImageMagick not found (need 'magick' or 'convert')." >&2
  exit 1
fi

if [[ $# -lt 2 ]]; then
  echo "Usage: $0 <source-image> <output-dir>"
  exit 1
fi

SRC="$1"
OUT="${2%/}"
mkdir -p "$OUT"

make_png() {
  local size="$1" dest="$2"
  $IM "$SRC" \
    -alpha on -background none \
    -resize "${size}x${size}" \
    -gravity center -extent "${size}x${size}" \
    "PNG32:${dest}"
}

make_maskable() {
  local size="$1" dest="$2"
  local inner=$(((size * 70) / 100))
  $IM "$SRC" \
    -alpha on -background none \
    -resize "${inner}x${inner}" \
    -gravity center -extent "${size}x${size}" \
    "PNG32:${dest}"
}

echo "→ Generating core icons..."
make_png 192 "$OUT/icon-192.png"
make_png 512 "$OUT/icon-512.png"
make_maskable 192 "$OUT/icon-maskable-192.png"
make_maskable 512 "$OUT/icon-maskable-512.png"
make_png 180 "$OUT/apple-touch-icon.png"

echo "→ Generating favicon.ico..."
tmpdir="$(mktemp -d)"
trap 'rm -rf "$tmpdir"' EXIT

for s in 16 32 48; do
  $IM "$SRC" -alpha on -background none \
    -resize "${s}x${s}" \
    -gravity center -extent "${s}x${s}" \
    "PNG32:${tmpdir}/${s}.png"
done

$IM "${tmpdir}/16.png" "${tmpdir}/32.png" "${tmpdir}/48.png" "$OUT/favicon.ico"

echo "✅ Done. Wrote minimal PWA icons to: $OUT"