#! /bin/bash
#
# symlink all files in an src directory to a target directory
#
# usage: link2 [options] srcDir [targetDir]
#     -v | --verbose	Echo command names
#     -d | --debug	Additional debugging output
#     -h | --help		This text
#     -n | --dry-run	Do not execute
#     -r | --remove 	Remove link/file if it exists
#
# targetDir is created (mkdir -p) if it does not exist.   Existing
# symlinks are replaced.
#

# Examples:
#
#  Link all files in /etc to ./etc, creating ~./etc if needed
#
#    $ linkall -v /etc
#  
#
#  Link all files in ~/git/public/dotfiles to $HOME, replacing existing links
#
#    $ linkall ~/git/public/dotfiles $HOME
#

# Author:
#   George Jones

set -e -u

PROG_NAME=$0
PROG_NAME=`basename $0`
SHORT_OPTS='vdhnrs:'
LONG_OPTS='verbose,debug,dry-run,help,remove,stack-size:'
OPTS=`getopt -o $SHORT_OPTS --long $LONG_OPTS -n 'parse-options' -- "$@"`

function usage() {
  cat <<END >&2
usage: $PROG_NAME [options] srcDir targetDir
    -v | --verbose	Echo command names
    -d | --debug	Additional debugging output
    -h | --help		This text
    -n | --dry-run	Do not execute
    -r | --remove 	Remove link/file if it exists
END
exit 1
}

if [ $? != 0 ] ; then echo "Failed parsing options." >&2 ; exit 1 ; fi

eval set -- "$OPTS"

# Default values

VERBOSE=false
HELP=false
DRY_RUN=false
STACK_SIZE=0
DEBUG=false
REMOVE=false

# Set user selected options

while true; do
  case "$1" in
    -v | --verbose ) VERBOSE=true; shift ;;
    -d | --debug ) DEBUG=true; shift ;;
    -h | --help )    HELP=true; shift ;;
    -n | --dry-run ) DRY_RUN=true; shift ;;
    -r | --remove ) REMOVE=true; shift ;;
    -s | --stack-size ) STACK_SIZE="$2"; shift; shift ;;
    -- ) shift; break ;;
    * ) break ;;
  esac
done

if $DEBUG; then
  VERBOSE=true
fi

if $DEBUG; then
    echo VERBOSE=$VERBOSE
    echo DEBUG=$DEBUG
    echo HELP=$HELP
    echo DRY_RUN=$DRY_RUN
    echo REMOVE=$REMOVE
    echo STACK_SIZE=$STACK_SIZE
fi

# validate arguments

if [[ "$STACK_SIZE" =~ '"^[0-9]+$' ]]; then
  echo "$PROG_NAME: stack_size must be an integer.  Got /$STACK_SIZE/" >&2
  usage
fi


# get file arguments

if [ "$#" -lt 1 ]; then
  echo $PROG_NAME: missing srcDir
  usage
fi

if $HELP; then
  usage
fi

srcDir=$1
targetDir=${2:-"${PWD}"}

# figure out the link target, make sure it exists

if [ ! -d ${srcDir} ]; then
  echo $0: ${srcDir} does not exist or is not a directory>&2
  exit 1
fi


# Make sure targetDir exists, creating if necessary


if [ -d `readlink -f "${targetDir}"` ]; then
  if $DRY_RUN || $VERBOSE; then
  	echo ${targetDir} exists
  fi

elif [ -e "${targetDir}" ]; then
  echo $0: ${targetDir} exists but is not  or is not a directory>&2
  exit 1
else
  if $DRY_RUN || $VERBOSE; then
  	echo mkdir -p  ${targetDir}
  fi
  mkdir -p "${targetDir}"
fi



# Link all files in $srcDir to $targetDir

cd "$srcDir"

for f in `ls -1 -a`; do

  if [ "$f" == '.' ] || [ "$f" == '..' ]; then
    continue
  fi

  if $DRY_RUN || $VERBOSE; then
        echo rm -f  "$targetDir/$f" || true
  fi

  rm -f  "$targetDir/$f" || true
  ln -s  "$srcDir/$f" "$targetDir"
done