Interactive and visual selection of array with arrows or 'j' 'k' keys. Can also edit (with autocomplete) the selection

file_menu2.bash

#!/usr/bin/env bash

# Started from this code: https://unix.stackexchange.com/a/415155/14014
# Renders a text based list of options that can be selected by the
# user using up, down, 'j', 'k',  and enter keys and returns the
# string in provided file. 
#    'e' to edit the current string
#    'q' to quit
#
#   Arguments   : list of options, maximum of 256
#                 "file_to_return_string_in.txt" "opt1" "opt2" ...
#   Return value:
#   Ex:
#       files=( $( ls -at -1 /sims/$PROJ/results/$USER/*.svcf ) )
#       return_val=$( mktemp )
#       select_option $return_val "${files[@]}"
#       echo "Returned str = " $( cat $return_val )

function select_option {
    return_val=$1 && shift
    args=( $@ )

    # 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_option()     { printf "   $1 "; }
    print_selected()   { printf "  $ESC[7m $1 $ESC[27m"; }
    get_cursor_row()   { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }

    key_input()        { read -r -s -n1 key 2>/dev/null >&2
                         if [[ $key = $ESC ]]; then
                           read -r -s -n1 key 2>/dev/null >&2
                           if [[ $key = [ ]]; then
                             read -r -s -n1 key 2>/dev/null >&2
                             if [[ $key = A ]]; then echo up;    fi
                             if [[ $key = B ]]; then echo down;  fi
                           fi
                         fi
                         if [[ $key = k      ]]; then echo up;    fi
                         if [[ $key = j      ]]; then echo down;  fi
                         if [[ $key = ""     ]]; then echo enter; fi
                         if [[ $key = e      ]]; then echo edit;  fi
                         if [[ $key = q      ]]; then echo quit;  fi
                       }

    # initially print empty new lines (scroll down if at bottom of screen)
    for opt; do printf "\n"; done

    # determine current screen position for overwriting the options
    local lastrow=`get_cursor_row`
    local startrow=$(($lastrow - $#))

    # 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

    local edit=''
    local selected=0
    while true; do
        # print options by overwriting the last lines
        local idx=0
        for opt; do
            cursor_to $(($startrow + $idx))
            if [ $idx -eq $selected ]; then
                print_selected "$opt"
            else
                print_option "$opt"
            fi
            ((idx++))
        done

        # user key control
        case `key_input` in
            enter) break;;
            quit) return 0;;
            edit) edit='true' && break;;
            up)    ((selected--));
                   if [ $selected -lt 0 ]; then selected=$(($# - 1)); fi;;
            down)  ((selected++));
                   if [ $selected -ge $# ]; then selected=0; fi;;
        esac
    done

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

    output="${args[$selected]}"

    if [[ $edit == true ]]; then
        read -e -p "Edit selection: " -i $output output
    fi
    echo "$output" >> $return_val
}