#!/bin/sh
# the pxe-linking skript should be executed every new hour
# crontab entry:  0 * * * *  root <absolute-path>/pxelink.sh

pxedir='tftpboot/pxe/pxelinux.cfg/'
cd $pxedir
# delete all symbolic links (they are obsolete)
rm 01-*
if [ -e default ] ; then rm default ; fi

# get actual time parameters (weekday and hour)
datum=`date +%a:%-k |sed 's/[a-z]/\U&/g'`
wday=`echo $datum | cut -d ":" -f 1`
time=`echo $datum | cut -d ":" -f 2`
echo "actual time: " $wday $time

# get all PXE files (unique) under <timerange>/<pxefile>
pxenumber=`find -type f | cut -d "/" -f 3 | sort | sed '$!N; /^\(.*\)
  \n\1$/!P; D' | wc -l`
pxe=`find -type f | cut -d "/" -f 3 | sort | sed '$!N; /^\(.*\)\n\1$
  /!P; D' `
for ((j=0;j<$pxenumber;j++)) ; do
  pxe_array[$j]=`echo $pxe | cut -d " " -f $[$j+1] `
  echo "pxe file: " ${pxe_array[j]}
  lines=`find */${pxe_array[j]} | cut -d "/" -f 1 | wc -l`
  ranges=`find */${pxe_array[j]} | cut -d "/" -f 1`
  for ((i=0;i<$lines;i++)) ; do
    timerange[$i]=`echo $ranges | cut -d " " -f $[$i+1] `
    #echo ${timerange[i]}
  done
  match=0

  # get timerange corresponding to actual time parameters
  while true; do	
    for ((i=0;i<$lines;i++)) ; do
      trday=`echo ${timerange[i]} | cut -d "_" -f 1`
      trbegin=`echo ${timerange[i]} | cut -d "_" -f 2`
      trend=`echo ${timerange[i]} | cut -d "_" -f 3`
      if [ $trday != "X" ] && [ $trbegin != "X" ] && [ $trday == $wday ] \
          && [ $trbegin -le $time ] && [ $time -le $trend ]; then
        echo $wday $time "[D H H]match ->" ${timerange[i]}
        ln -s ${timerange[i]}'/'${pxe_array[j]} ${pxe_array[j]}
        echo "symlink: " ${pxe_array[j]} "->" ${timerange[i]}"/"${pxe_array[j]}
        match=1 && break
      fi
    done
    if [ $match == 1 ] ; then break ; fi

    for ((i=0;i<$lines;i++)) ; do
      trday=`echo ${timerange[i]} | cut -d "_" -f 1`
      trbegin=`echo ${timerange[i]} | cut -d "_" -f 2`
      trend=`echo ${timerange[i]} | cut -d "_" -f 3`
      if [ $trday == $wday ] && [ $trbegin == "X" ] && [ $trend == "X" ]; then
        echo $wday $time "[D _ _]match ->" ${timerange[i]}
        ln -s ${timerange[i]}"/"${pxe_array[j]} ${pxe_array[j]}
        echo "symlink: " ${pxe_array[j]} "->" ${timerange[i]}"/"${pxe_array[j]}
        match=1 && break
      fi
    done
    if [ $match == 1 ] ; then break ; fi

    for ((i=0;i<$lines;i++)) ; do
      trday=`echo ${timerange[i]} | cut -d "_" -f 1`
      trbegin=`echo ${timerange[i]} | cut -d "_" -f 2`
      trend=`echo ${timerange[i]} | cut -d "_" -f 3`
      if [ $trday == "X" ] && [ $trbegin != "X" ] && [ $trend != "X" ] && \
          [ $trbegin -le $time ] && [ $time -le $trend ]; then
        echo $wday $time "[_ H H]match ->" ${timerange[i]}
        ln -s ${timerange[i]}"/"${pxe_array[j]} ${pxe_array[j]}
        echo "symlink: " ${pxe_array[j]} "->" ${timerange[i]}"/"${pxe_array[j]}
        match=1 && break
      else
        if [ ${timerange[i]} == "X_X_X" ]; then
          echo $wday $time "[_ _ _]match ->" ${timerange[i]}
          ln -s ${timerange[i]}"/"${pxe_array[j]} ${pxe_array[j]}
          echo "symlink: " ${pxe_array[j]} "->" ${timerange[i]}"/"${pxe_array[j]}
        fi
        match=1
      fi
    done 
    if [ $match == 1 ] ; then break ; fi
  done
done
exit 0