install

#!/usr/bin/env bash
#
# dotfiles/install
#
# Usage:
#   cd ~/.dotfiles
#   ./install -n   to see what would happen
#
#
# 
MY_HOME=${HOME}
#
usage() {
  cat <<EOF
usage $0 [options]

OPTIONS:
  -h     Show this message
  -n     Show what this script would do (but don't do it).

EOF
}


#
# List of exluded files
excluded=(README.md LICENSE `basename $0` configuration)

## Parse command line switches
while getopts "hn" option
do
case $option in
        h)
            usage
            exit
            ;;
        n)
            DRY_RUN=1
            ;;
        ?)
            usage
            exit 1
             ;;
    esac
done
shift $(($OPTIND -1))
args=${*}  # remaining args

# ----------------------------------------------------------- utilities
info_indent="                  "
info () {
  printf "%s\033[00;34m..\033[0m %s\n"  "${info_indent}" "$1"
}

task () {
  printf "\033[00;34m * %-12s \033[0m: " $1
}

success () {
  printf "[\033[00;32mOK\033[0m] $1\n"
}

warn () {
  printf "[\033[0;31mWARN\033[0m] $1\n"
}

fail () {
  printf "\033[2K [\033[0;31mFAIL\033[0m] $1\n"
  echo ''
  exit
}


# ----------------------------------------------------------- backup
# backup stuff
#
backup_dir=$MY_HOME/.dotfiles_backup
timestamp=$(date '+%Y%m%d_%H%M%S')

if ! [[ -x "${backup_dir}" ]]; then
  echo "-> Creating a backup directory for existing dotfiles."
  mkdir -p ${backup_dir}
fi

backup() {
  local old_file=$1
  local basename=$(basename $old_file)
  local backup_file="${backup_dir}/${basename#.}-${timestamp}"
  #
  info "Looking for backups"
  local -a bfiles=($(find ${backup_dir} -name "${basename#.}*"))
  local n=${#bfiles[@]}
  if [[ $n -gt 0 ]]; then
    local last_backup=${bfiles[((${n}-1))]}
    if $(diff "${old_file}" "${last_backup}" > /dev/null); then
      info "Matches '${last_backup}'"
      rm ${old_file} && info "=> Removed current file."
      return 0
    fi
  fi
  mv $old_file $backup_file && \
    info "Backed up to ${backup_file}."
}


# ------------------------------------------------------------ main
# main
#
files=(`dirname $0`/*)
for file in ${files[@]}; do
  f_basename=$(basename $file)
  if [[ "${excluded[@]}" =~ "${f_basename}" ]]; then
    continue;
  fi
  target="${MY_HOME}/.${f_basename}"
  # shortcut for `basename`
  task "${target##*/}"
  if [ -e $target ]; then
    if $(diff "${file}" "${target}" > /dev/null) ; then
      success "up-to-date"
      continue
    else
      warn "Found real file '${file}'!"
      backup $target
      printf "$info_indent"
    fi
  fi
  ln -s $file $target && \
    success "Installed link to ${file}."
done