#
# based on http://theoldschooldevops.com/2008/02/09/bash-ini-parser/
#

PREFIX="cfg_section_"

function debug {
   if  ! [ -v "BASH_INI_PARSER_DEBUG" ]
   then 
      #abort debug
      return
   fi
   echo $*
   echo --start--
   echo "${ini[*]}"
   echo --end--
   echo
}

function cfg_parser {
   shopt -p extglob &> /dev/null
   CHANGE_EXTGLOB=$?
   if [ $CHANGE_EXTGLOB = 1 ]
   then
      shopt -s extglob
   fi
   ini="$(<$1)"                 # read the file
   ini=${ini//$'\r'/}           # remove linefeed i.e dos2unix

   ini="${ini//[/\\[}"
   debug "escaped ["
   ini="${ini//]/\\]}"
   debug "escaped ]"
   IFS=$'\n' && ini=( ${ini} )  # convert to line-array
   debug
   ini=( ${ini[*]/#*([[:space:]]);*/} )
   debug "remove ; comments"
   ini=( ${ini[*]/#*([[:space:]])\#*/} )
   debug "remove # comments"
   ini=( ${ini[*]/#+([[:space:]])/} ) # remove init whitespace
   debug
   ini=( ${ini[*]/%+([[:space:]])/} ) # remove ending whitespace
   debug "whitespace around ="
   ini=( ${ini[*]/*([[:space:]])=*([[:space:]])/=} ) # remove whitespace around =
   debug
   ini=( ${ini[*]/#\\[/\}$'\n'"$PREFIX"} ) # set section prefix
   debug
   ini=( ${ini[*]/%\\]/ \(} )   # convert text2function (1)
   debug
   ini=( ${ini[*]/=/=\( } )     # convert item to array
   debug
   ini=( ${ini[*]/%/ \)} )      # close array parenthesis
   debug
   ini=( ${ini[*]/%\\ \)/ \\} ) # the multiline trick
   debug
   ini=( ${ini[*]/%\( \)/\(\) \{} ) # convert text2function (2)
   debug
   ini=( ${ini[*]/%\} \)/\}} )  # remove extra parenthesis
   ini=( ${ini[*]/%\{/\{$'\n''cfg_unset ${FUNCNAME/#'$PREFIX'}'$'\n'} )  # clean previous definition of section 
   debug
   ini[0]=""                    # remove first element
   debug
   ini[${#ini[*]} + 1]='}'      # add the last brace
   debug
   eval "$(echo "${ini[*]}")"   # eval the result
   EVAL_STATUS=$?
   if [ $CHANGE_EXTGLOB = 1 ]
   then
      shopt -u extglob
   fi
   return $EVAL_STATUS
}

function cfg_writer {
   SECTION=$1
   OLDIFS="$IFS"
   IFS=' '$'\n'
   if [ -z "$SECTION" ] 
   then
      fun="$(declare -F)"
   else
      fun="$(declare -F $PREFIX$SECTION)"
      if [ -z "$fun" ]
      then
         echo "section $SECTION not found" 1>&2
         exit 1
      fi
   fi
   fun="${fun//declare -f/}"
   for f in $fun; do
      [ "${f#$PREFIX}" == "${f}" ] && continue
      item="$(declare -f ${f})"
      item="${item##*\{}" # remove function definition
      item="${item##*FUNCNAME*$PREFIX\};}" # remove clear section
      item="${item/FUNCNAME\/#$PREFIX;}" # remove line
      item="${item/\}}"  # remove function close
      item="${item%)*}" # remove everything after parenthesis
      item="${item});" # add close parenthesis
      vars=""
      while [ "$item" != "" ]
      do
         newvar="${item%%=*}" # get item name
         vars="$vars$newvar" # add name to collection
         item="${item#*;}" # remove readed line
      done
      vars=$(echo "$vars" | sort -u) # remove duplication
      eval $f
      echo "[${f#$PREFIX}]" # output section
      for var in $vars; do
         eval 'local length=${#'$var'[*]}' # test if var is an array
         if [ $length == 1 ]
         then
            echo $var=\"${!var}\" #output var
         else 
            echo ";$var is an array" # add comment denoting var is an array
            eval 'echo $var=\"${'$var'[*]}\"' # output array var
         fi
      done
   done
   IFS="$OLDIFS"
}

function cfg_unset {
   SECTION=$1
   OLDIFS="$IFS"
   IFS=' '$'\n'
   if [ -z "$SECTION" ] 
   then
      fun="$(declare -F)"
   else
      fun="$(declare -F $PREFIX$SECTION)"
      if [ -z "$fun" ]
      then
         echo "section $SECTION not found" 1>&2
         return
      fi
   fi
   fun="${fun//declare -f/}"
   for f in $fun; do
      [ "${f#$PREFIX}" == "${f}" ] && continue
      item="$(declare -f ${f})"
      item="${item##*\{}" # remove function definition
      item="${item##*FUNCNAME*$PREFIX\};}" # remove clear section
      item="${item/\}}"  # remove function close
      item="${item%)*}" # remove everything after parenthesis
      item="${item});" # add close parenthesis
      vars=""
      while [ "$item" != "" ]
      do
         newvar="${item%%=*}" # get item name
         vars="$vars $newvar" # add name to collection
         item="${item#*;}" # remove readed line
      done
      for var in $vars; do
         unset $var
      done
   done
   IFS="$OLDIFS"
}

function cfg_clear {
   SECTION=$1
   OLDIFS="$IFS"
   IFS=' '$'\n'
   if [ -z "$SECTION" ] 
   then
      fun="$(declare -F)"
   else
      fun="$(declare -F $PREFIX$SECTION)"
      if [ -z "$fun" ]
      then
         echo "section $SECTION not found" 1>&2
         exit 1
      fi
   fi
   fun="${fun//declare -f/}"
   for f in $fun; do
      [ "${f#$PREFIX}" == "${f}" ] && continue
      unset -f ${f}
   done
   IFS="$OLDIFS"
}

function cfg_update {
   SECTION=$1
   VAR=$2
   OLDIFS="$IFS"
   IFS=' '$'\n'
   fun="$(declare -F $PREFIX$SECTION)"
   if [ -z "$fun" ]
   then
      echo "section $SECTION not found" 1>&2
      exit 1
   fi
   fun="${fun//declare -f/}"
   item="$(declare -f ${fun})"
   #item="${item##* $VAR=*}" # remove var declaration
   item="${item/\}}"  # remove function close
   item="${item}
    $VAR=(${!VAR})
   "
   item="${item}
   }" # close function again

   eval "function $item"
}

#Test harness
if [ $# != 0 ]
then
   $@
fi
# vim: filetype=sh