#!/usr/bin/env bash
#
# Automatically types the username and password from the pass entry specified
# as argument one. The required password-store backend is pass, the standard
# unix password manager.
#
# A simple workflow for this may be to go to a website requiring a username and
# password. Select the username field, open a program launcher such as rofi or
# dmenu, then execute 'quicktype password-name'.
#
# Note that for this to work, each pass entry must match the following criteria
# * The password is on the first line (this is the pass standard)
# * The username can be anywhere in the file, but the line must look like
#   'username: <password>'
# 
# Depends on: pass xdotool
#


export PASSWORD_STORE_DIR=~/.password-store


#
# Writes log output to terminal and notification daemon, if one is present.
#
function log {
  local msg="${@}"

  if [[ $(type -p notify-send) != '' ]]; then
    notify-send "$(basename ${0}):" "${msg}"
  fi
  printf -- '%s\n' "${msg}"
}


#
# Ensures required tools are available, returning code 1 and log if any of them
# are not.
#
function check_env {
  # Verify pass is installed and in the PATH.
  if [[ $(type -p pass) == '' ]]; then
    log "Error: Could not find pass." && return 1
  fi

  # Verify xdotool is installed and in the path
  if [[ $(type -p xdotool) ==  '' ]]; then
    log "Error: Could not find xdotool." && return 1
  fi

  # Verify /dev/null is a character device, on the off chance someone with root
  # access is trying to capture output redirected there.
  local devstat=$(ls -l /dev/null)
  if [[ ${devstat:0:1} != 'c' ]]; then
    log "Error: /dev/null is not a character device."
    return 1
  fi

  return 0
}


#
# Gets a field's value from the specified [multiline] string, using the
# specified delimiter.
#
# @param content Content to extract field value from
# @param delim   Delimiter seperating fields and values
# @param field   Field name to get value for
#
getfield() {
  local _content="${1:-}"
  local _delim="${2:-}"
  local _field="${3:-}"

  printf -- "%s" "${_content}" \
    | sed -n "s/${_field}${_delim} *\(.*\)/\1/p" \
    | head -n 1
}


typefields() {
  local _user="${1:-}"
  local _pass="${2:-}"
  local _delim="${3:-}"

  # Type the password
  xdotool type --delay 15 "${_user}"
  xdotool key "${_delim}"
  xdotool type --delay 15 "${_pass}"
}


pastefields() {
  local _user="${1:-}"
  local _pass="${2:-}"
  local _delim="${3:-}"

  # Save clipboard first
  local _origclipboard="$(xclip -o -selection clipboard)"

  # Sleep .2 for those apps that read only "key up" events without first reading
  # "key down", causing it to read pressing enter to execute pt as submitting
  # the form (bad js devs, bad!).
  sleep .2
  # Save username to clipboard and paste
  printf -- "%s\n" "${_user}" | xclip -selection clipboard
  xdotool key "Control+v" "${_delim}"

  # Save password to clipboard and paste
  printf -- "%s\n" "${_pass}" | xclip -selection clipboard
  xdotool key "Control+v"

  # Restore original clipboard value
  printf -- "%s\n" "${_origclipboard}" | xclip -selection clipboard
}


function main {
  local _passentry    # Contents of the requested pass entry
  local _passpassword # Password from the pass entry
  local _passusername # Username field from the pass entry
  local _passdelim    # UI Field delimiter (Tab, Return), from the pass entry
  local _passsubmit   # Boolean submit (1,y,yes...), from the pass entry
  local _passtype     # Boolean type (1,y,yes...), from the pass entry

  local _delim=Tab    # Default delimiter if not specified in pass entry
  local _submit=0     # Default submit value if not specified in pass entry
  local _type=0       # Whether or not to type or paste (type=0 will paste)

  # Exit failure if no password was specified
  [[ -z ${1} ]] && log "Please specify a password to be typed" && exit 1

  check_env || exit 0
  
  # Check if the password exists in the store
  # Also, copy the contents into a variable if it exists
  _passentry="$(pass ${@} 2>/dev/null)"
  [[ $? -gt 0 ]] && log "Error: '${@}' is not in the password store" && exit 1
  
  # Parse pass output into appropriate variables 
  _passpassword=$(printf -- "%s" "${_passentry}" | head -n1 | sed 's/`/\`/g')
  _passusername=$(getfield "${_passentry}" ':' 'username')
  _passdelim=$(getfield    "${_passentry}" ':' 'delim')
  _passsubmit=$(getfield   "${_passentry}" ':' 'submit')
  _passtype=$(getfield     "${_passentry}" ':' 'type')

  # If any of the known 'submit' values are specified, set submit to 1
  if [ "${_passsubmit}" = '1' ] \
    || [ "${_passsubmit}" = 'y' ] \
    || [ "${_passsubmit}" = 'yes' ] \
    || [ "${_passsubmit}" = 'true' ]; then
    _submit=1
  fi

  # If any of the known 'type' values are specified, set type to 1
  if [ "${_passtype}" = '1' ] \
    || [ "${_passtype}" = 'y' ] \
    || [ "${_passtype}" = 'yes' ] \
    || [ "${_passtype}" = 'true' ]; then
    _type=1
  fi

  # Type username/password if type == 1, otherwise paste username/password
  if [ "${_type}" = '1' ]; then
    typefields "${_passusername}" "${_passpassword}" "${_delim}"
  else
    pastefields "${_passusername}" "${_passpassword}" "${_delim}"
  fi
  
  [ "${_submit}" = 1 ] && xdotool key Return
}

main ${@}