#!/bin/bash
#
# html_updateHeadings.sh -- This function transforms html headings to
# to make them accessible (e.g., through a table of contents).  In
# order for this function to work, you need to put headings in just
# one line and they must have one of the following formats:
#
# <h1><a name="">Title</a></h1>
# <h1><a href="">Title</a></h1>
# <h1><a name="" href="">Title</a></h1>
#
# In the above examples, h1 can vary from h1 to h6. Closing tag must
# be present and match the openning tag. The value of <a name=""> and
# <a href=""> options are the md5sum of page location, plus the
# 'head-' string, plus the heading string. If heading title or page
# location changes, the values of <a name=""> and <a href=""> options
# will change too.
#
# Copyright (C) 2009-2011 Alain Reguera Delgado
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
# ----------------------------------------------------------------------
# $Id$
# ----------------------------------------------------------------------

function tuneup_doXhtmlHeadings {

    # Define variables as local to avoid conflicts outside.
    local COUNT=0
    local PREVCOUNT=0
    local PATTERN=''
    local -a FINAL
    local -a TITLE
    local -a MD5SM
    local -a OPTNS
    local -a LEVEL
    local -a PARENT
    local -a TOCENTRIES
    local -a LINK

    # Define html heading regular expression pattern. Use parenthisis
    # to save html action name, action value, and heading title.
    PATTERN="<h([1-6])>(<a.*[^\>]>)(.*[^<])</a></h[1-6]>"

    # Verify list of html files. Are files really html files? If they
    # don't, continue with the next one in the list.
    if [[ ! $(file --brief $FILE) =~ '^(XHTML|HTML|XML)' ]];then
        continue
    fi

    # Define list of headings to process. When building the heading,
    # it is required to change spaces characters from its current
    # decimal output to something different (e.g., its \040 octal
    # alternative). This is required because the space character is
    # used as egrep default field separator and spaces can be present
    # inside heading strings we don't want to separate.
    for HEADING in $(egrep "$PATTERN" $FILE \
        | sed -r -e 's!^[[:space:]]+!!' -e "s! !\\\040!g");do

        # Define previous counter value using current counter
        # value as reference.
        if [[ $COUNT -ne 0 ]];then
            PREVCOUNT=$(($COUNT-1))
        fi

        # Define initial heading information.
        FIRST[$COUNT]=$(echo $HEADING | sed -r "s!\\\040! !g")
        TITLE[$COUNT]=$(echo ${FIRST[$COUNT]} | sed -r "s!$PATTERN!\3!")
        MD5SM[$COUNT]=$(echo "${FILE}${FIRST[$COUNT]}" | md5sum | sed -r 's![[:space:]]+-$!!')
        OPTNS[$COUNT]=$(echo ${FIRST[$COUNT]} | sed -r "s!$PATTERN!\2!")
        LEVEL[$COUNT]=$(echo ${FIRST[$COUNT]} | sed -r "s!$PATTERN!\1!")
        PARENT[$COUNT]=${LEVEL[$PREVCOUNT]}

        # Transform heading information using initial heading
        # information as reference.
        if [[ ${OPTNS[$COUNT]} =~ '^<a (href|name)="(.*)" (href|name)="(.*)">$' ]];then
            OPTNS[$COUNT]='<a name="head-'${MD5SM[$COUNT]}'" href="#head-'${MD5SM[$COUNT]}'">'
        elif [[ ${OPTNS[$COUNT]} =~ '^<a name="(.*)">$' ]];then 
            OPTNS[$COUNT]='<a name="head-'${MD5SM[$COUNT]}'">'
        elif [[ ${OPTNS[$COUNT]} =~ '^<a href="(.*)">$' ]];then
            OPTNS[$COUNT]='<a href="#head-'${MD5SM[$COUNT]}'">'
        fi

        # Build final html heading structure.
        FINAL[$COUNT]='<h'${LEVEL[$COUNT]}'>'${OPTNS[$COUNT]}${TITLE[$COUNT]}'</a></h'${LEVEL[$COUNT]}'>'

        # Build html heading link structure. These links are used by
        # the table of contents later.
        LINK[$COUNT]='<a href="#head-'${MD5SM[$COUNT]}'">'${TITLE[$COUNT]}'</a>'

        # Build table of contents entry with numerical
        # identifications. The numerical identification is what we use
        # to determine the correct position of each heading link on
        # the table of content.
        TOCENTRIES[$COUNT]="$COUNT:${LEVEL[$COUNT]}:${PARENT[$COUNT]}:${LINK[$COUNT]}"

        # Update heading information inside the current file being
        # processed. Use the first and final heading information.
        sed -i -r "s!${FIRST[$COUNT]}!${FINAL[$COUNT]}!" $FILE

        # Increase heading counter.
        COUNT=$(($COUNT + 1))

    done

    # Build the table of contents using heading numerical
    # identifications as reference. The numerical identification
    # describes the order of headings in one html file. This
    # information is processed by awk to make the appropriate
    # replacements. Finnally, the result is stored in the TOC
    # variable.
    TOC=$(echo '<div class="toc">'
        echo "<h3>`gettext "Table of contents"`</h3>"
        for TOCENTRY in "${TOCENTRIES[@]}";do
            echo $TOCENTRY
        done \
            | awk -f ${FUNCCONFIG}/output_forHeadingsToc.awk)

    # Update table of contents inside the current file being
    # processed.
    sed -i -r '/<div class="toc">[^<\/div].*<\/div>/c'"$(echo -e $TOC)" $FILE

    # Reset counters.
    COUNT=0
    PREVCOUNT=0

    # Clean up variables to receive the next file.
    unset FINAL
    unset TITLE
    unset MD5SM
    unset OPTNS
    unset LEVEL
    unset PARENT
    unset TOCENTRIES
    unset LINK

}