Interactive select list

startup.sh

@@ -17,6 +17,69 @@ set_option() {
     fi
     echo "${1}=${2}" >>$CONFIG_FILE # add option
 }
+# Renders a text based list of options that can be selected by the
+# user using up, down and enter keys and returns the chosen option.
+#
+#   Arguments   : list of options, maximum of 256
+#                 "opt1" "opt2" ...
+#   Return value: selected index (0 for opt1, 1 for opt2 ...)
+select_option() {
+
+    # little helpers for terminal print control and key input
+    ESC=$( 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 -s -n3 key 2>/dev/null >&2
+                         if [[ $key = $ESC[A ]]; then echo up;    fi
+                         if [[ $key = $ESC[B ]]; then echo down;  fi
+                         if [[ $key = ""     ]]; then echo enter; fi; }
+
+    # initially print empty new lines (scroll down if at bottom of screen)
+    for opt; do printf "\n"; done
+
+    # determine current screen position for overwriting the options
+    local lastrow=`get_cursor_row`
+    local startrow=$(($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 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;;
+            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
+
+    return $selected
+}
 logo () {
 # This will be shown on every set as user is progressing
 echo -ne "
@@ -36,17 +99,16 @@ filesystem () {
 # This function will handle file systems. At this movement we are handling only
 # btrfs and ext4. Others will be added in future.
 echo -ne "
-    Please Select your file system for both boot and root
-    1)      btrfs
-    2)      ext4
-    3)      luks with btrfs
-    0)      exit
+Please Select your file system for both boot and root
 "
-read fs
+options=("btrfs" "ext4" "luks" "exit")
+select_option "${options[@]}"
+fs=$?
+
 case $fs in
-1) set_option FS btrfs;;
-2) set_option FS ext4;;
-3) 
+0) set_option FS btrfs;;
+1) set_option FS ext4;;
+2) 
 while true; do
   echo -ne "Please enter your luks password: \n"
   read -s luks_password # read password without echo
@@ -63,54 +125,60 @@ while true; do
   fi
 done
 ;;
-0) exit ;;
+3) exit ;;
 *) echo "Wrong option please select again"; filesystem;;
 esac
 }
 timezone () {
 # Added this from arch wiki https://wiki.archlinux.org/title/System_time
 time_zone="$(curl --fail https://ipapi.co/timezone)"
-echo -ne "System detected your timezone to be '$time_zone' \n"
-echo -ne "Is this correct? yes/no:" 
-read answer
-case $answer in
+echo -ne "
+System detected your timezone to be '$time_zone' \n"
+echo -ne "Is this correct?
+" 
+options=("Yes" "No")
+select_option "${options[@]}"
+choice=$?
+
+case ${options[$choice]} in
     y|Y|yes|Yes|YES)
+    echo "${time_zone} set as timezone"
     set_option TIMEZONE $time_zone;;
     n|N|no|NO|No)
     echo "Please enter your desired timezone e.g. Europe/London :" 
     read new_timezone
+    echo "${new_timezone} set as timezone"
     set_option TIMEZONE $new_timezone;;
     *) echo "Wrong option. Try again";timezone;;
 esac
 }
 keymap () {
-# These are default key maps as presented in official arch repo archinstall
-options=(by ca cf cz de dk es et fa fi fr gr hu il it lt lv mk nl no pl ro ru sg ua uk us)
 PS3="
+
 Please select key board layout from this list
 
 "
-select keymap in "${options[@]}"
-do
-# check if selection is part of list, silence error output and use else block for output
-if echo -e '%s\n' "${options[@]}" | grep -Fqw $keymap 2> /dev/null; then
-    echo -e "\nYour key boards layout: ${keymap} \n"
-    set_option KEYMAP $keymap
-    break
-else
-    echo -e "\nInvalid selection, please try again. \n"
-fi
+# These are default key maps as presented in official arch repo archinstall
+options=(by ca cf cz de dk es et fa fi fr gr hu il it lt lv mk nl no pl ro ru sg ua uk us)
 
-done
+select_option "${options[@]}"
+choice=$?
+keymap=${options[$choice]}
+
+echo -ne "\nYour key boards layout: ${keymap} \n"
+set_option KEYMAP $keymap
 }
 
 drivessd () {
 echo -ne "
 Is this an ssd? yes/no:
 "
-read ssd_drive
 
-case $ssd_drive in
+options=("Yes" "No")
+select_option "${options[@]}"
+choice=$?
+
+case ${options[$choice]} in
     y|Y|yes|Yes|YES)
     set_option MOUNT_OPTIONS "noatime,compress=zstd,ssd,commit=120";;
     n|N|no|NO|No)
@@ -133,19 +201,13 @@ echo -ne "
 PS3='
 Select the disk to install on: '
 options=($(lsblk -n --output TYPE,KNAME,SIZE | awk '$1=="disk"{print "/dev/"$2"|"$3}'))
-select disk in "${options[@]}"
-do
 
-# check if selection is part of list, silence error output and use else block for output
-if echo -e '%s\n' "${options[@]}" | grep -Fqw ${disk} 2> /dev/null; then
-    echo -e "\n${disk%|*} selected \n"
+select_option "${options[@]}"
+choice=$?
+disk=${options[$choice]%|*}
+
+echo -e "\n${disk%|*} selected \n"
     set_option DISK ${disk%|*}
-    break
-else
-    echo -e "\nInvalid selection, please try again. \n"
-fi
-
-done
 
 drivessd
 }