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

URL="https://didawiki.cli.di.unipi.it/doku.php/matematica/ro/start"
BASE="https://didawiki.cli.di.unipi.it"
TMPDIR=$(mktemp -d)

cleanup() { rm -rf "$TMPDIR"; }
trap cleanup EXIT

if [[ "${1:-}" == "--with-solutions" ]]; then
    PREFIX="sc"
    OUTFILE="soluzioni_ro_merge.pdf"
    echo "Fetching Svolgimenti PDFs..."
else
    PREFIX="c"
    OUTFILE="testi_ro_merge.pdf"
    echo "Fetching Testi PDFs..."
fi

curl -s "$URL" \
    | grep -oP "/lib/exe/fetch\.php/matematica/ro/${PREFIX}\d{6}\.pdf" \
    | sort -u \
    | while read -r path; do
        filename=$(basename "$path")
        echo "  Downloading $filename"
        curl -s -o "$TMPDIR/$filename" "${BASE}${path}"
    done

echo ""
echo "Merging PDFs into $OUTFILE..."
gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile="$OUTFILE" "$TMPDIR"/*.pdf

echo "Done → $OUTFILE ($(wc -c < "$OUTFILE") bytes)"