# Simple bourne shell based stopwatch
# Requires 'kvs' and the id 'stopwatch' therein
# so make sure you set 'kvs' before sourcing this script if necessary.
#
# After loading, the following commands are available:
#
# Start a stopwatch:
#   stopwatch <tag> start
#
# 'Lap' a stopwatch
#   stopwatch <tag> lap
#
# Stop a stopwatch
#   stopwatch <tag> stop
#
# Reset a stopwatch
#   stopwatch <tag> reset


if [ -z "${__stopwatch_sh_loaded}" ]
then
  __stopwatch_sh_loaded=yes

  [ "${kvs}" ] || kvs="$(mktemp -t ".stopwatch.XXXXXXXX")"
  want kvs

  stopwatch_help() {
    echo "Usage: stopwatch <tag> <start|lap|stop|reset>" >&2
    exit 1
  }

  # Try and format a passed integer number of seconds into something more
  # useful (like 6m10s or something)
  _stopwatch_timefmt() {
    local secs mins hurs days
    [ "${1}" -a "$(echo "${1}" | tr -Cd '0-9')" = "${1}" ] || return 255
    secs="${1}"
    mins=0
    hurs=0
    [ "${secs}" -lt 60 ] || {
      mins=$(( ${secs} / 60 ))
      secs=$(( ${secs} % 60 ))
    }
    [ "${secs}" -gt 0 ] || secs=""
    [ "${mins}" -lt 60 ] || {
      hurs=$(( ${mins} / 60 ))
      mins=$(( ${mins} % 60 ))
    }
    [ "${mins}" -gt 0 ] || mins=""
    [ "${hurs}" -lt 24 ] || {
      days=$(( ${hurs} / 24 ))
      hurs=$(( ${hurs} % 24 ))
    }
    [ "${hurs}" -gt 0 ] || hurs=""

    [ "${days}" -o "${hurs}" -o "${mins}" -o "${secs}" ] || printf "0s"
    printf "%s%s%s%s" "${days:+${days}d}" "${hurs:+${hurs}h}" "${mins:+${mins}m}" "${secs:+${secs}s}"
  }

  # Start a named stopwatch, but do nothing if the named stopwatch is already
  # running.
  stopwatch_start() {
    name="${1:-stopwatch}"
    [ "${nao}" ] || nao="$(date +%s)"
    # Is the stopwatch running?
    if kvs_has_key stopwatch "${name}"
    then
      printf "Stopwatch: %s is already running.\n" "${name}"
    else
      # start the stopwatch
      accum="$(kvs_get stopwatch "${name}_accumulator")"
      kvs_set stopwatch "${name}" "${nao}"
      [ "${accum}" ] && restart="$(printf " at %s" "$(_stopwatch_timefmt "${accum}")")"
      printf "Stopwatch: %s starts running%s.\n" "${name}" "${restart}"
    fi
  }

  # 'Lap' the named stopwatch: print out a line indicating how long the named
  # stopwatch has been running, but do not stop nor reset the stopwatch.
  stopwatch_lap() {
    name="${1:-stopwatch}"
    [ "${nao}" ] || nao="$(date +%s)"
    # Is the stopwatch running?
    if kvs_has_key stopwatch "${name}"
    then
      # emit a line indicating how long it has been running
      start="$(kvs_get stopwatch "${name}")"
      accum="$(kvs_get stopwatch "${name}_accumulator")"
      delta="$(( ${nao} - ${start} ))"
      [ "${accum}" ] && delta="$(( ${delta} + ${accum} ))"
      printf "Stopwatch: %s is running at %s.\n" "${name}" "$(_stopwatch_timefmt "${delta}")"
    else
      accum="$(kvs_get stopwatch "${name}_accumulator")"
      [ "${accum}" ] && printf "Stopwatch: %s is stopped at %s.\n" "${name}" "$(_stopwatch_timefmt "${accum}")"
    fi
  }

  # Stop the named stopwatch and print out a line indicating how long it had
  # been running up until that point; do not reset the stopwatch.
  stopwatch_stop() {
    name="${1:-stopwatch}"
    [ "${nao}" ] || nao="$(date +%s)"
    if kvs_has_key stopwatch "${name}"
    then
      start="$(kvs_get stopwatch "${name}")"
      accum="$(kvs_get stopwatch "${name}_accumulator")"
      delta="$(( ${nao} - ${start} ))"
      [ "${accum}" ] && delta="$(( ${delta} + ${accum} ))"
      kvs_set stopwatch "${name}_accumulator" "${delta}"
      kvs_unset stopwatch "${name}"
      printf "Stopwatch: %s stops running at %s.\n" "${name}" "$(_stopwatch_timefmt "${delta}")"
    else
      accum="$(kvs_get stopwatch "${name}_accumulator")"
      [ "${accum}" ] && printf "Stopwatch: %s is already stopped at %s.\n" "${name}" "$(_stopwatch_timefmt "${accum}")"
    fi
  }

  # Reset the named stopwatch back to zero.
  stopwatch_reset() {
    name="${1:-stopwatch}"
    [ "${nao}" ] || nao="$(date +%s)"
    kvs_unset stopwatch "${name}"
    kvs_unset stopwatch "${name}_accumulator"
    printf "Stopwatch: %s is reset to 0s.\n" "${name}"
  }

  stopwatch() {
    [ "${1}" -a "${2}" ] || stopwatch_help;
    nao="$(date +%s)"
    case "${2}" in
    [Ss][Tt][Aa][Rr][Tt])  stopwatch_start "${1}"  ;;
    [Ll][Aa][Pp])          stopwatch_lap "${1}"    ;;
    [Ss][Tt][Oo][Pp])      stopwatch_stop "${1}"   ;;
    [Rr][Ee][Ss][Ee][Tt])  stopwatch_reset "${1}"  ;;
    *)                     stopwatch_help          ;;
    esac
  }
fi