#!/bin/bash

BASE="${1:-.}"

for dir in "$BASE"/*/; do
    [ -d "$dir" ] || continue

    title=$(basename "$dir")

    # Skip directories starting with a number
    [[ "$title" =~ ^[0-9] ]] && continue

    # Author = parent directory of book directory
    author=$(basename "$(dirname "$dir")")

    # Fix author name formatting
    author="${author//JRR/J. R. R.}"

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

        opf="$dir/metadata.opf"

        cat > "$opf" <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<package xmlns:dc="http://purl.org/dc/elements/1.1/"
         xmlns:opf="http://www.idpf.org/2007/opf"
         version="2.0">
  <metadata>
    <dc:title>$title</dc:title>
    <dc:creator opf:role="aut">$author</dc:creator>
    <dc:language>en</dc:language>
    <dc:format>application/pdf</dc:format>
  </metadata>
</package>
EOF

        echo "Created: $opf"
    done
done