#!/bin/sh
# conf2env.sh
# convert config to envdir
# wcm, 2004.01.21 - 2004.01.22
# ===

# usage:
#
#   conf2env envdir
#
ENVDIR=$1

usage(){
  cat <<END_USAGE
$0 usage:

    cat myfile.conf | $0 envdir

* reads configuration file (key=value format) from stdin
* writes output into envdir specified in argument envdir

END_USAGE
}


if [ "X"${ENVDIR} = "X" ] ; then
  usage
  exit 1
fi

if [ ! -d ${ENVDIR} ] ; then
  echo "error: ${ENVDIR} directory not found"
  exit 1
fi

##
## cleanup input:
sed '
# ignore blank lines, commented lines:
/^$/d
/^ *$/d
/^#/d
# strip leading/trailing blanks:
s/^  *//
s/  *$//
# strip spaces before/after '=':
s/  *\=  */\=/
# strip quotes from quoted values:
s/\="/\=/
s/"$//
# collapse remaining whitespace:
s/[	 ][	 ]*/ /g
# sub tab for key/value field separator:
s/\=/	/
' | \
##
## split key/values and output:
awk -v envdir=${ENVDIR} '
##
## variable "envdir" set from command-line
##
BEGIN {
  FS="\t"
  STDERR="/dev/stderr"
}

{
  if (NF==2) {
    key = $1
    value = $2
    # value may include recursively defined values:
    n = split(value, subval, " ")
    for(i = 1; i <= n; ++i){
      v = subval[i]
      if(v ~ /^\$/){
        sub(/^\$/, "", v)
        if (!sub(/\$[[:alnum:]]+/, values[v], value)){
          print "Unexpected error: RECURSIVE SUBSTITUTION FAILURE:" $0 > STDERR
        }
      }
    }
    values[key] = value
    system("rm -f "envdir"/"key)
    if(system("echo "value" > "envdir"/"key)){
      print "Unexpected error: WRITE ERROR:" $0 > STDERR
    } 
  }
  else {
    print "Unexpected error: EXCESS FIELDS:" $0 > STDERR
  }
}
'
##
## all done:
exit 0

### that's all, folks!