#!/bin/bash
######################################################################
#
#   tcar - The CentOS Artwork Repository automation tool.
#   Copyright © 2014 The CentOS Artwork SIG
#
#   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.
#
#   Alain Reguera Delgado <al@centos.org.cu>
#   39 Street No. 4426 Cienfuegos, Cuba.
#
######################################################################

# Transform web page headings to make them accessible through a table
# of contents.  The table of contents is expanded in place, wherever
# the <div class="toc"></div> piece of code be in the page.  Once the
# <div class="toc"></div> piece of code has be expanded, there is no
# need to put anything else in the page.
#
# In order for the tuneup functionality to transform headings, you
# need to put headings in just one line using one of the following
# forms:
#
#   <h1><a name="">Title</a></h1>
#   <h1><a href="">Title</a></h1>
#   <h1><a name="" href="">Title</a></h1>
#
# In the example above, h1 can vary from h1 to h6. Closing tag must be
# present and also match the openning tag. The value of `name' and
# `href' options from the anchor element are set dynamically using the
# md5sum output of combining the page location, the head- string and
# the heading string.
function xhtml_setToc {

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

    # Define table of content configuration file, the file used to
    # produce the table of content XHTML output code.
    local TOC_CONFIG=${TCAR_MODULE_DIR_CONFIGS}/toc.awk

    # Verify table of content configuration file.
    tcar_checkFiles -ef ${TOC_CONFIG}

    # Define html heading regular expression pattern. Use parenthisis
    # to save html action name, action value, and heading title.
    local 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}!\4!")
        MD5SM[${COUNT}]=$(echo "${TITLE[${COUNT}]}" | md5sum | sed -r 's![[:space:]]+-$!!')
        OPTNS[${COUNT}]=$(echo "${FIRST[${COUNT}]}" | sed -r "s!${PATTERN}!\3!")
        CLASS[${COUNT}]=$(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[${COUNT}]}${CLASS[${COUNT}]}'>'${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 xhtml file. This
    # information is processed by awk to make the appropriate
    # replacements. Finnally, the result is stored in the TOC
    # variable.
    TOC=$(echo '<div class="toc">'
        echo "<p>`gettext "Table of contents"`</p>"
        for TOCENTRY in "${TOCENTRIES[@]}";do
            echo ${TOCENTRY}
        done \
            | awk -f ${TOC_CONFIG})

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

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

}