#!/bin/sh

function help {
  echo "NAME"
  echo "  $(basename $0) - import an OpenSSH key from a file or from stdin"
  echo ""
  echo "SYNOPSYS"
  echo "  $(basename $0) -n NAME [-f FILE]"
  echo ""
  echo "OPTIONS"
  echo "  -n, --name=KEYNAME"
  echo "    The key name, e.g. \"id\", which would result in a private key file ~/.ssh/id_rsa,"
  echo "    ~/.ssh/id_dsa, ~/.ssh/id_ecdsa or .ssh/id_ed25519 (depending on the key type)."
  echo ""
  echo "  -f, --file=FILE"
  echo "    The file containing the private key that will be imported. If this option is not"
  echo "    specified, the private key will be read from stdin."
  echo ""
  echo "  -h, --help"
  echo "    Display this help message."
  echo ""
  echo "AUTHOR"
  echo "  Written by Christian Ulrich, christian@ulrich.earth"
}

function import {
  local private_key="$1"
  local name="$2"

  local public_key=$(ssh-keygen -yf /dev/stdin <<< $private_key)
  local type=$(
    ssh-keygen -lf /dev/stdin <<< $public_key |
    rev |
    cut -d" " -f1 |
    rev |
    tr -d '()' | 
    tr '[:upper:]' '[:lower:]')
  local private_key_file=~/.ssh/${name}_${type}
  local public_key_file=~/.ssh/${name}_${type}.pub
  echo "$private_key" > $private_key_file
  chmod 0600 $private_key_file
  echo "$public_key" > $public_key_file
  chmod 0644 $public_key_file
  echo "Successfully imported key."
  echo "Private key stored at ${private_key_file}"
  echo "Public key stored at ${public_key_file}"
}

function main {
  while [[ $# -gt 0 ]]; do
    local opt="$1"
    case $opt in
      -n|--name)
	local name="$2"
	shift
      	shift
	;;
      -f|--file)
        local file_path="$2"
	shift
	shift
	;;
      -h|--help)
	help
	return 0
	;;
      *)
	help
	return 1
    esac
  done

  if [ -z "$name" ]; then
    help
    return 1
  fi

  if [ -z "$file_path" ]; then
    local private_key=$(</dev/stdin)
  else
    local private_key=$(<$file_path)
  fi
 
  import "$private_key" "$name"
}

set -e
main "$@"