make-books

#!/bin/bash

# Prerequisites: xmllint
# Usage:         ./make-books

# Variables
declare -a books=()
book_regex='name="([^"]+)"\s+entry="([^"]+)"' # 'name="xyz" entry="xyz"'
song_regex='(\w+)\s+(.+)'
book_xml=$(cat <<END
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?xml-stylesheet href="../stylesheets/book.xsl" type="text/xsl"?>
<book
 xmlns="http://docbook.org/ns/docbook" version="5.0"
 xmlns:ol="http://openlyrics.info/namespace/2009/song"
 xmlns:xi="http://www.w3.org/2001/XInclude"
 xml:id="id-of-the-book"
 xml:lang="en">
  <title>Title of the book</title>
  <preface>
    <title>Title</title>
    <para>Lorem ipsum</para>
  </preface>
  <toc>
    <title>TOC</title>
  </toc>
  <chapter version="">
    <title>Songs</title>
    INCLUDES  </chapter>
</book>
END
)
function join_by { local IFS="$1"; shift; echo "$*"; }

for file in songs/*.xml; do
  echo "Processing... $file"
  # get related songbooks and entries
  # xpath -e "/song/properties/songbooks/songbook/@name
  # xpath -e "/song/properties/songbooks/songbook/@entry
  # together:
  # xpath -e "/song/properties/songbooks/songbook/@*[name()='name' or name()='entry']"
  item=$(xmllint --xpath "/*[local-name()='song']/*[local-name()='properties']/*[local-name()='songbooks']/*[local-name()='songbook']/@*[name()='name' or name()='entry']" "$file") 

  if [[ $item == 'XPath set is empty' ]]; then
    continue
  fi
  
  # generate book content 
  while [[ $item =~ $book_regex ]]; do
      book=${BASH_REMATCH[1]}
      entry=${BASH_REMATCH[2]}
      # if file does not exists, create them
      if [ ! -f "$book" ]; then
          books+=("$book")
          touch "$book"
      fi
      # append to file 
      echo -e "$entry" '\t' "$file" >> "$book"
      # remove last match, next
      item=${item##*"${BASH_REMATCH[0]}"}
  done
done

for i in "${books[@]}"; do
  # sort books by entries
  sort -g "$i" -o "$i"

  # create real XML from temp file
  declare -a axml=()
  while IFS= read -r line; do
    if [[ $line =~ $song_regex ]]; then
      axml+=("    <xi:include href=\"../${BASH_REMATCH[2]}\" parse=\"xml\" />")
    fi
  done < "$i"
  xml=$(join_by $'\n' "${axml[@]}")
  # Remove temporary file
  rm "$i"
 
  # write to a file
  if [[ -e "books/$i.xml" ]]; then
    echo "Updating TOC... $i"
    # file exists, update content
    sed -i '/<xi:include/d' "books/$i.xml"
    gawk -i inplace -v "xml=$xml" '/<\/chapter>/{print xml}1' "books/$i.xml"
  else
    echo "Creating TOC... $i"
    # File none exists, creat a new XML and write it to file
    inc=${book_xml/INCLUDES/$xml}
    touch "books/$i.xml"
    echo "$inc" >> "books/$i.xml"
  fi
done