# readlineSync
# https://github.com/anseki/readline-sync
#
# Copyright (c) 2015 anseki
# Licensed under the MIT license.

# getopt(s)
while [ $# -ge 1 ]; do
  arg="$(printf '%s' "$1" | grep -E '^-+[^-]+$' | tr '[A-Z]' '[a-z]' | tr -d '-')"
  case "$arg" in
    'display')          shift; options_display="$1";;
    'keyin')            options_keyIn=true;;
    'noechoback')       options_noEchoBack=true;;
    'mask')             shift; options_mask="$1";;
    'limit')            shift; options_limit="$1";;
    'caseSensitive')    options_caseSensitive=true;;
    'encoded')          options_encoded=true;;
  esac
  shift
done

reset_tty() {
  if [ -n "$save_tty" ]; then
    stty --file=/dev/tty "$save_tty" 2>/dev/null || \
      stty -F /dev/tty "$save_tty" 2>/dev/null || \
      stty -f /dev/tty "$save_tty" || exit $?
  fi
}
trap 'reset_tty' EXIT
save_tty="$(stty --file=/dev/tty -g 2>/dev/null || stty -F /dev/tty -g 2>/dev/null || stty -f /dev/tty -g || exit $?)"

write_tty() { # 2nd arg: enable escape sequence
  if [ "$2" = true ]; then
    printf '%b' "$1" >/dev/tty
  else
    printf '%s' "$1" >/dev/tty
  fi
}

replace_allchars() { (
  text=''
  for i in $(seq 1 ${#1})
  do
    text="$text$2"
  done
  printf '%s' "$text"
) }

[ -z "$options_display" ] && [ "$options_keyIn" = true ] && \
  [ "$options_noEchoBack" = true ] && [ -z "$options_mask" ] && silent=true
[ "$options_noEchoBack" != true ] && [ "$options_keyIn" != true ] && is_cooked=true

if [ -n "$options_display" ]; then
  write_tty "$options_display"
fi

if [ "$is_cooked" = true ]; then
  stty --file=/dev/tty cooked 2>/dev/null || \
    stty -F /dev/tty cooked 2>/dev/null || \
    stty -f /dev/tty cooked || exit $?
else
  stty --file=/dev/tty raw -echo 2>/dev/null || \
    stty -F /dev/tty raw -echo 2>/dev/null || \
    stty -f /dev/tty raw -echo || exit $?
fi

[ "$options_keyIn" = true ] && req_size=1

if [ "$options_keyIn" = true ] && [ -n "$options_limit" ]; then
  if [ "$options_caseSensitive" = true ]; then
    limit_ptn="$options_limit"
  else
    # Safe list
    limit_ptn="$(printf '%s' "$options_limit" | sed 's/\([a-z]\)/\L\1\U\1/ig')"
  fi
fi

while :
do
  if [ "$is_cooked" != true ]; then
    chunk="$(dd if=/dev/tty bs=1 count=1 2>/dev/null)"
  else
    IFS= read -r chunk </dev/tty || exit $?
    chunk="$(printf '%s\n_NL_' "$chunk")"
  fi

  # Don't assign '\n' to chunk.
  if [ -n "$chunk" ] && [ "$(printf '%s' "$chunk" | tr '\r' '\n' | wc -l)" != "0" ]; then
    chunk="$(printf '%s' "$chunk" | tr '\r' '\n' | head -n 1)"
    at_eol=true
  fi

  # other ctrl-chars
  if [ -n "$chunk" ]; then
    # chunk="$(printf '%s' "$chunk" | tr -d '\00-\10\13\14\16-\37\177')"
    # for System V
    chunk="$(printf '%s' "$chunk" | tr -d '\00\01\02\03\04\05\06\07\10\13\14\16\17\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37\177')"
  fi
  if [ -n "$chunk" ] && [ -n "$limit_ptn" ]; then
    chunk="$(printf '%s' "$chunk" | tr -cd "$limit_ptn")"
  fi

  if [ -n "$chunk" ]; then
    if [ "$is_cooked" != true ]; then
      if [ "$options_noEchoBack" != true ]; then
        write_tty "$chunk"
      elif [ -n "$options_mask" ]; then
        write_tty "$(replace_allchars "$chunk" "$options_mask")"
      fi
    fi
    input="$input$chunk"
  fi

  if ( [ "$options_keyIn" != true ] && [ "$at_eol" = true ] ) || \
    ( [ "$options_keyIn" = true ] && [ ${#input} -ge $req_size ] ); then break; fi
done

if [ "$is_cooked" != true ] && [ "$silent" != true ]; then write_tty '\r\n' true; fi

printf "'%s'" "$input"

exit 0