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

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
SOURCE_MD="$ROOT_DIR/docs/de/user_manual.md"
SCREENSHOT_DIR="$ROOT_DIR/docs/de/screenshots"
OUTPUT_PDF="$ROOT_DIR/docs/de/user_manual.pdf"

if ! command -v pandoc >/dev/null 2>&1; then
  echo "Error: Pandoc is not installed or not available in PATH." >&2
  echo "Install Pandoc first, then run this script again." >&2
  exit 1
fi

if [[ ! -f "$SOURCE_MD" ]]; then
  echo "Error: source Markdown not found: $SOURCE_MD" >&2
  exit 1
fi

PDF_ENGINE=""
for candidate in xelatex lualatex tectonic pdflatex wkhtmltopdf weasyprint; do
  if command -v "$candidate" >/dev/null 2>&1; then
    PDF_ENGINE="$candidate"
    break
  fi
done

if [[ -z "$PDF_ENGINE" ]]; then
  echo "Error: no Pandoc-compatible PDF engine found." >&2
  echo "Install xelatex, lualatex, tectonic, wkhtmltopdf, or weasyprint." >&2
  exit 1
fi

TMP_DIR="$(mktemp -d)"
trap 'rm -rf "$TMP_DIR"' EXIT
TMP_MD="$TMP_DIR/user_manual.md"
export XDG_CACHE_HOME="$TMP_DIR/cache"
mkdir -p "$XDG_CACHE_HOME/fontconfig"

python3 - "$SOURCE_MD" "$TMP_MD" "$SCREENSHOT_DIR" <<'PY'
import pathlib
import re
import sys

source = pathlib.Path(sys.argv[1])
target = pathlib.Path(sys.argv[2])
screenshot_dir = pathlib.Path(sys.argv[3])
document_dir = screenshot_dir.parent

markdown = source.read_text(encoding="utf-8")
image_pattern = re.compile(r"!\[([^\]]*)\]\((screenshots/[^)]+)\)")


def replace_missing_image(match):
    alt_text = match.group(1).strip()
    image_ref = match.group(2)
    image_path = document_dir / image_ref

    if image_path.exists():
        return match.group(0)

    label = alt_text or pathlib.PurePosixPath(image_ref).name
    return f"*Screenshot placeholder: {label}*"


target.write_text(image_pattern.sub(replace_missing_image, markdown), encoding="utf-8")
PY

pandoc "$TMP_MD" \
  --from markdown+pipe_tables+grid_tables+multiline_tables+implicit_figures \
  --resource-path="$ROOT_DIR/docs/de" \
  --pdf-engine="$PDF_ENGINE" \
  --toc \
  --toc-depth=2 \
  --number-sections \
  --syntax-highlighting=tango \
  --wrap=preserve \
  -V papersize:a4 \
  -V geometry:margin=20mm \
  -V lang=de-DE \
  -V colorlinks=true \
  -o "$OUTPUT_PDF"

echo "User manual PDF generated successfully: $OUTPUT_PDF"