#!/bin/bash

cmd=""
timeoutSeconds=60
sleepSeconds=1
message=""
messageInterval=5
startTimeSeconds=$(date +%s)
elapsedSeconds=0
attempts=0

print_usage() {
    echo "Usage: $0 [options] <command>"
    echo
    echo "Attempts to execute a given command periodically until it succeeds or a timeout occurs."
    echo
    echo "Options:"
    echo "  -t, --timeout           The maximum number of seconds to wait for the command to succeed (default: 60)"
    echo "  -s, --sleep             The number of seconds to sleep for between command attempts (default: 1)"
    echo "  -m, --message           The progress message to print after every attempt (default: '')"
    echo "                          Instances of {{elapsed}} and {{attempts}} in the message will be replaced by total"
    echo "                          elapsed time (in seconds) and total attempts respectively."
    echo "  -i, --message-interval  The number of command attempts to make before each printing of the progress message"
    echo "                          (default: 5)."
    echo " -e, --exit-command       Optional command to run before exiting (default: '')"
    echo
}

print_progress() {
  if [ -n "$message" ]; then
    echo "$message" | sed "s/{{attempts}}/$attempts/g; s/{{elapsed}}/$elapsedSeconds/g"
  fi
}

# Parse options and arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        -t | --timeout)
            shift
            timeoutSeconds="$1"
            ;;
        -s | --sleep)
            shift
            sleepSeconds="$1"
            ;;
        -m | --message)
            shift
            message="$1"
            ;;
        -i | --message-interval)
            shift
            messageInterval="$1"
            ;;
        -e | --exit-command)
            shift
            exitCommand="$1"
            ;;
        *)
            cmd="$@"
            break
            ;;
    esac
    shift
done

# Error if no command was provided
if [ -z "$cmd" ]; then
    print_usage
    exit 1
fi

# Loop until either the command succeeds or a timeout occurs.
until [ "$elapsedSeconds" -gt "$timeoutSeconds" ] || eval "$cmd"; do
    sleep "$sleepSeconds"

    # Increment attempt counter. If we've hit the message interval, print the message
    attempts=$((attempts + 1))
    if [ $((attempts % messageInterval)) -eq 0 ]; then
        print_progress
    fi

    # Recalculate $elapsedSeconds
    currentTimeSeconds=$(date +%s)
    elapsedSeconds=$((currentTimeSeconds - startTimeSeconds))
done

# If we timed out, print the final progress message and exit with code 1.
if [ "$elapsedSeconds" -gt "$timeoutSeconds" ]; then
  print_progress
  if [ -n "$exitCommand" ]; then
    eval "$exitCommand"
  fi
  exit 1
fi