#! /bin/bash
#
# -- create compatibility symlinks from a new style LDP output tree to the
#    earlier filesystem layout:
#
# -- License:  GPLv2
#
# -- written for TLDP in January 2016; Martin A. Brown <martin@linux-ip.net>
#
#
#          old                        new
#    -------------------           -----------------------
#    ${STEM}/${STEM}.txt           html/HOWTO/text/${STEM}
#    ${STEM}/${STEM}.pdf           html/HOWTO/pdf/${STEM}.pdf
#    ${STEM}/${STEM}.html          html/${STEM}.html
#    ${STEM}/${STEM}-single.html   html/HOWTO/html_single/${STEM}/index.html
#
#

set -e
# set -x

SELFNAME="$( readlink --canonicalize ${0})"
ME="${SELFNAME##*/}"  # -- basename
DIR="${SELFNAME%/*}"  # -- dirname

# -- my favorite shell functions (and their offspring)
#
gripe  () { printf >&2 "%s\n" "$@"; }
debug  () { : ; }  # -- NOOP for now
notice () { gripe "${ME}[$$]: $@"; }
abort  () { 
   EXIT_CODE="${1}" && shift;
   gripe "E: $@"; 
   exit $EXIT_CODE;
}

usage () {
  abort 1 "usage: ${ME} <newtree> <oldtree>";
}

test "$#" -eq 2 || usage

NEWTREE="$( readlink --canonicalize $1 )"   && shift
OLDTREE="$( readlink --canonicalize $1 )"   && shift

notice "Will walk all documents in $NEWTREE"
notice "Will create symlinks under $OLDTREE"

DRYRUN=echo

cd "$NEWTREE" \
  || abort 1 "Could not \"cd $NEWTREE\""

find . -mindepth 1 -maxdepth 1 -type d -printf "%P\n" \
  | sort | while read STEM ; do

  cd "${OLDTREE}" \
    || abort 1 "Could not \"cd $OLDTREE\""

  # HTML chunked outputs
  #
  unset DOC_HTML
  NEWFILE="${NEWTREE}/${STEM}/${STEM}.html"
  for OLDFILE in html/HOWTO/${STEM}/index.html html/HOWTO/${STEM}.html html/FAQ/${STEM}/index.html html/LDP/${STEM}/html/index.html ; do
    if test -e "$OLDFILE"; then
      DOC_HTML=$OLDFILE
      notice "$STEM symlinking (html)  $OLDFILE (to $NEWFILE)"
      $DRYRUN ln -srf --backup=simple --suffix="-$( date +%F-%T)" -- "$NEWFILE" "$OLDFILE"
      break
    else
      : # -- noop
      #notice "$STEM missing    (html)  $OLDFILE"
    fi
  done

  # HTML single file outputs for HOWTO and GUIDE document categories
  #
  unset DOC_HTMLS
  NEWFILE="${NEWTREE}/${STEM}/${STEM}-single.html"
  for OLDFILE in html/HOWTO/html_single/${STEM}/index.html html/LDP/${STEM}/html/${STEM}.html ; do
    if test -e "$OLDFILE"; then
      DOC_HTMLS=$OLDFILE
      notice "$STEM symlinking (htmls) $OLDFILE (to $NEWFILE)"
      $DRYRUN ln -srf --backup=simple --suffix="-$( date +%F-%T)" -- "$NEWFILE" "$OLDFILE"
      break
    else
      : # -- noop
      #notice "$STEM missing    (htmls) $OLDFILE"
    fi
  done

    
  unset DOC_TXT
  NEWFILE="${NEWTREE}/${STEM}/${STEM}.txt"
  for OLDFILE in html/{FAQ/faqs,HOWTO/text}/${STEM} html/{LDP,REF}/${STEM}/${STEM}.txt ; do
    if test -e "$OLDFILE"; then
      DOC_TXT=$OLDFILE
      notice "$STEM symlinking (text)  $OLDFILE (to $NEWFILE)"
      $DRYRUN ln -srf --backup=simple --suffix="-$( date +%F-%T)" -- "$NEWFILE" "$OLDFILE"
      break
    else
      : # -- noop
      #notice "$STEM missing    (text)  $OLDFILE"
    fi
  done

  unset DOC_PDF
  NEWFILE="${NEWTREE}/${STEM}/${STEM}.pdf"
  for OLDFILE in html/{HOWTO,FAQ}/pdf/${STEM}.pdf html/{LDP,REF}/${STEM}/${STEM}.pdf ; do
    if test -e "$OLDFILE"; then
      DOC_PDF=$OLDFILE
      notice "$STEM symlinking (pdf)   $OLDFILE (to $NEWFILE)"
      $DRYRUN ln -srf --backup=simple --suffix="-$( date +%F-%T)" -- "$NEWFILE" "$OLDFILE"
      break
    else
      : # -- noop
      #notice "$STEM missing    (pdf)   $OLDFILE"
    fi
  done

  for var in DOC_HTML DOC_HTMLS DOC_TXT DOC_PDF; do

    if test -n "${!var}"; then
      notice "$STEM ${var}   ${!var}" 
    else
      notice "$STEM ${var}   not found"
    fi

  done

done

# -- add some special handling for:
#
#    solrhe
#
# -- end of file