#!/bin/bash
# =================================================== #
# llxcfg-template                                     #
#                                                     #
# Escrito por Luis García <garcia_luigis@gva.es>      #
# para LliureX. Marzo 2006                            #
#                                                     #
#    Utilidad para procesamiento de plantillas        #
# =================================================== #
#

set -e


# variables
LLXCFG_TMPL="llxcfg-tmpl v 0.1"

usage(){
   echo "Usage: $0 [--no-gpp] {TEMPLATE_FILE|-} [INCLUDE_FILE1 INCLUDE_FILE2 ... ]" >&2
   exit 0
}

expand_var_list(){
   local TEMPLATE_FILE="$1"
   shift
   sed_var_list_command $@ |sed -f - "$TEMPLATE_FILE"
}

sed_var_list_command(){
   local VAR_NAME SED_CMD
   for VAR_NAME in $@; do
      SED_CMD="s%_@_${VAR_NAME}_@_%${!VAR_NAME}%g;"
      echo ${SED_CMD}
   done
}

list_expand_vars(){
   local SOURCE_FILE VAR_LIST0 VAR_LIST VAR_NAME
   SOURCE_FILE="$1"
   VAR_LIST0=`sed -ne "s%.*_@_\([^[:space:]]*\)_@_.*%\1%p" ${SOURCE_FILE}`
   VAR_LIST=""
   for VAR_NAME in ${VAR_LIST0}; do
      echo " ${VAR_LIST} " |grep -q " ${VAR_NAME} " || VAR_LIST="${VAR_LIST} ${VAR_NAME}"
   done
   echo "${VAR_LIST}"
}

gen_include_file(){
   cat << EOF
#define LLXTMPL
#define LLXTMPL_HEADER(x) x## Automatically generated with ${LLXCFG_TMPL}. Date: #date %F %R:%S ##
#define LLXTMPL_TESTVAR(x) x !=
EOF
}

expand_template(){
   local SOURCE_FILE EXTRA_INCLUDES INCLUDE_FILE TEMP_FILE TEMP_FILE1 TEMP_FILE2 INC_FILE OLD_SOURCE EXPAND_VARS 
   SOURCE_FILE="$1"
   shift
   EXTRA_INCLUDES="$@"
   INCLUDE_FILE="`tempfile`"
   TEMP_FILE1="`tempfile`"
   TEMP_FILE2="`tempfile`"
   
   # generamos include file
   gen_include_file > ${INCLUDE_FILE}
   # añadimos los ficheros extra si existen
   for INC_FILE in ${EXTRA_INCLUDES}; do
      [ -f ${INC_FILE} ] && cat ${INC_FILE} >> ${INCLUDE_FILE}
   done

   # obtenemos la lista de variables referenciadas en la plantilla,
   # las leemos y procesamos la plantilla
   # se hace en un bucle mientras queden variables por expandir
   # lo que permite usar variables que contienen otras variables ...
   cat ${SOURCE_FILE} > ${TEMP_FILE1}
   SOURCE_FILE="${TEMP_FILE1}"
   TEMP_FILE="${TEMP_FILE2}"
   EXPAND_VARS="`list_expand_vars ${SOURCE_FILE}`"
   while [ "${EXPAND_VARS}" ]; do
      eval `/usr/sbin/llxcfg-showvars ${EXPAND_VARS}`
      expand_var_list "${SOURCE_FILE}" ${EXPAND_VARS} > ${TEMP_FILE}
      OLD_SOURCE=${SOURCE_FILE}
      SOURCE_FILE=${TEMP_FILE}
      TEMP_FILE=${OLD_SOURCE}
      EXPAND_VARS="`list_expand_vars ${SOURCE_FILE}`"
   done
   # procesamos la plantilla con gpp, si produce errores la devolvemos tal cual
   SOURCE_PATH="`dirname ${SOURCE_FILE}`"
   if [ -z "$NO_GPP" ] ; then
      gpp -I${SOURCE_PATH} --include ${INCLUDE_FILE} ${SOURCE_FILE} > ${TEMP_FILE} && SOURCE_FILE="${TEMP_FILE}"
   fi
   cat ${SOURCE_FILE}
   rm -f ${INCLUDE_FILE}
   rm -f ${TEMP_FILE1}
   rm -f ${TEMP_FILE2}
   return 0
}

########
# main #
########
if [ "$1" = "--no-gpp" ] ; then
   NO_GPP="Y"
   shift
fi 

TMPL_FILE="$1"
DELETE_FILE=""
[ "${TMPL_FILE}" ] || usage

if [ "${TMPL_FILE}" = "-" ] ; then
   TMPL_FILE="$(tempfile)"
   DELETE_FILE="$TMPL_FILE"
   cat - > "${TMPL_FILE}"
fi
   
[ -f "${TMPL_FILE}" ] || usage
shift
INCLUDE_LIST="$@"

expand_template ${TMPL_FILE} ${INCLUDE_LIST}
if [ "$DELETE_FILE" ] ; then
   rm -f "$DELETE_FILE"
fi
exit 0