citadel-core/cli/utils/multiselect.sh

#!/usr/bin/env bash
set -euo pipefail

function multiselect() {
  # little helpers for terminal print control and key input
  ESC=$(printf "\033")
  cursor_blink_on() { printf "$ESC[?25h"; }
  cursor_blink_off() { printf "$ESC[?25l"; }
  cursor_to() { printf "$ESC[$1;${2:-1}H"; }
  print_inactive() { printf "$2   $1 "; }
  print_active() { printf "$2  $ESC[7m $1 $ESC[27m"; }
  get_cursor_row() {
    IFS=';' read -sdR -p $'\E[6n' ROW COL
    echo ${ROW#*[}
  }

  local return_value=$1
  local -n options=$2
  local -n defaults=$3

  local selected=()
  for ((i = 0; i < ${#options[@]}; i++)); do
    if [[ ${defaults[i]} = "true" ]]; then
      selected+=("true")
    else
      selected+=("false")
    fi
    printf "\n"
  done

  # determine current screen position for overwriting the options
  local lastrow=$(get_cursor_row)
  local startrow=$(($lastrow - ${#options[@]}))

  # ensure cursor and input echoing back on upon a ctrl+c during read -s
  trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
  cursor_blink_off

  key_input() {
    local key
    IFS= read -rsn1 key 2>/dev/null >&2
    if [[ $key = "" ]]; then echo enter; fi
    if [[ $key = $'\x20' ]]; then echo space; fi
    if [[ $key = "k" ]]; then echo up; fi
    if [[ $key = "j" ]]; then echo down; fi
    if [[ $key = $'\x1b' ]]; then
      read -rsn2 key
      if [[ $key = [A || $key = k ]]; then echo up; fi
      if [[ $key = [B || $key = j ]]; then echo down; fi
    fi
  }

  toggle_option() {
    local option=$1
    if [[ ${selected[option]} == true ]]; then
      selected[option]=false
    else
      selected[option]=true
    fi
  }

  print_options() {
    # print options by overwriting the last lines
    local idx=0

    for option in "${options[@]}"; do
      local prefix="[ ]"

      if [[ ${selected[idx]} == true ]]; then
        prefix="[\e[38;5;46m✔\e[0m]"
      fi

      cursor_to $(($startrow + $idx))
      if [ $idx -eq $1 ]; then
        print_active "$option" "$prefix"
      else
        print_inactive "$option" "$prefix"
      fi

      idx=$((idx + 1))
    done
  }

  get_result() {
    local result=()
    for ((i = 0; i < ${#options[@]}; i++)); do
      if ${selected[i]}; then
        result+=(${options[i]})
      fi
    done

    echo "${result[@]}"
  }

  local active=0
  while true; do
    print_options $active

    # user key control
    case $(key_input) in
    space) toggle_option $active ;;
    enter)
      print_options -1
      break
      ;;
    up)
      active=$((active - 1))
      if [ $active -lt 0 ]; then active=$((${#options[@]} - 1)); fi
      ;;
    down)
      active=$((active + 1))
      if [ $active -ge ${#options[@]} ]; then active=0; fi
      ;;
    esac
  done

  # cursor position back to normal
  cursor_to $lastrow
  printf "\n"
  cursor_blink_on

  eval $return_value='("$(get_result)")'
}