countdown_with_spinner

countdown_with_spinner.sh

#!/usr/bin/env bash

# countdown_with_spinner
# Arguments:
#   $1: Duration to wait in seconds
#   $2: Animation interval in seconds (e.g., 0.1)
#   $3: Spinner characters (string)
#   $4: Custom format string (optional) - use %s for spinner, %d for time, %s for unit
#       Default: "%s Waiting %d %s..."
countdown_with_spinner() {
  local duration="${1:-10}"
  local interval="${2:-0.1}"
  local spinner="${3:-⣾⣽⣻⢿⡿⣟⣯⣷}"
  local format="${4:-%s Waiting %d %s...}"

  local spinner_len=${#spinner}
  local start_time=$(date +%s.%N)
  local end_time=$(bc <<< "$start_time + $duration")
  local spinner_counter=0
  local last_spinner_update=$start_time

  while true; do
    local current_time=$(date +%s.%N)
    local time_left=$(bc <<< "scale=2; $end_time - $current_time")

    # Exit if countdown complete
    if (( $(echo "$time_left <= 0" | bc -l) )); then
      break
    fi

    # Update spinner if interval has passed
    local time_since_spinner=$(bc <<< "scale=2; $current_time - $last_spinner_update")
    if (( $(echo "$time_since_spinner >= $interval" | bc -l) )); then
      spinner_counter=$(( (spinner_counter + 1) % spinner_len ))
      last_spinner_update=$current_time
    fi

    local spinner_char=${spinner:spinner_counter:1}
    # Always round up (ceiling), with minimum of 1
    local display_time=$(bc <<< "scale=0; if ($time_left > 0) { ($time_left + 0.999) / 1 } else { 1 }")

    # Ensure minimum of 1
    if [ "$display_time" -eq 0 ]; then
      display_time=1
    fi

    local unit="seconds"
    if [ "$display_time" -eq 1 ]; then
      unit="second"
    fi

    # Format and print the countdown
    printf "\r$(printf "$format" "$spinner_char" "$display_time" "$unit")  "

    # Sleep for a short time to update display smoothly
    sleep 0.05
  done

  # Clear the line
  printf "\r%*s\r" 50 ""
}

# Export the function for use in other scripts
export -f countdown_with_spinner