#!/bin/sh
set -euo pipefail

DPI="${DPI:-250}"          # override: DPI=200 ./convert-pdfs
JPEG_QUALITY="${Q:-85}"    # override: Q=80   ./convert-pdfs

for f in *.pdf; do
  [ -f "$f" ] || continue

  name="${f%.pdf}"
  tmpdir="$(mktemp -d "${name}.XXXXXX")"

  echo "Converting $f (DPI=$DPI, Q=$JPEG_QUALITY)..."

  cleanup() { rm -rf "$tmpdir"; }
  trap cleanup EXIT INT TERM

  pdftoppm -jpeg -r "$DPI" -jpegopt "quality=$JPEG_QUALITY" "$f" "$tmpdir/page"

  if ! ls "$tmpdir"/page-*.jpg >/dev/null 2>&1; then
    echo "ERROR: pdftoppm produced no JPEG pages for $f"
    exit 1
  fi

  tmpcbz="${name}.cbz.tmp"
  (cd "$tmpdir" && zip -q -r "../$tmpcbz" .)

  if [ ! -s "$tmpcbz" ]; then
    echo "ERROR: Failed to create CBZ for $f"
    exit 1
  fi

  if [ -e "${name}.cbz" ]; then
    echo "ERROR: ${name}.cbz already exists"
    exit 1
  fi

  mv "$tmpcbz" "${name}.cbz"

  trap - EXIT
  cleanup
  echo "✔ Converted $f → ${name}.cbz"
done