# alarm.awk --- set an alarm

#

# Requires getlocaltime() library function

#

# Arnold Robbins, arnold@skeeve.com, Public Domain

# May 1993

# Revised December 2010

# usage: alarm time [ "message" [ count [ delay ] ] ]

BEGIN {

    # Initial argument sanity checking

    usage1 = "usage: alarm time ['message' [count [delay]]]"

    usage2 = sprintf("\t(%s) time ::= hh:mm", ARGV[1])

    if (ARGC < 2) {

        print usage1 > "/dev/stderr"

        print usage2 > "/dev/stderr"

        exit 1

    }

    switch (ARGC) {

    case 5:

        delay = ARGV[4] + 0

        # fall through

    case 4:

        count = ARGV[3] + 0

        # fall through

    case 3:

        message = ARGV[2]

        break

    default:

        if (ARGV[1] !~ /[[:digit:]]?[[:digit:]]:[[:digit:]]{2}/) {

            print usage1 > "/dev/stderr"

            print usage2 > "/dev/stderr"

            exit 1

        }

        break

    }

    # set defaults for once we reach the desired time

    if (delay == 0)

        delay = 180    # 3 minutes

    if (count == 0)

        count = 5

    if (message == "")

        message = sprintf("\aIt is now %s!\a", ARGV[1])

    else if (index(message, "\a") == 0)

        message = "\a" message "\a"

    # split up alarm time

    split(ARGV[1], atime, ":")

    hour = atime[1] + 0    # force numeric

    minute = atime[2] + 0  # force numeric

    # get current broken down time

    getlocaltime(now)

    # if time given is 12-hour hours and it's after that

    # hour, e.g., `alarm 5:30' at 9 a.m. means 5:30 p.m.,

    # then add 12 to real hour

    if (hour < 12 && now["hour"] > hour)

        hour += 12

    # set target time in seconds since midnight

    target = (hour * 60 * 60) + (minute * 60)

    # get current time in seconds since midnight

    current = (now["hour"] * 60 * 60) + \

               (now["minute"] * 60) + now["second"]

    # how long to sleep for

    naptime = target - current

    if (naptime <= 0) {

        print "alarm: time is in the past!" > "/dev/stderr"

        exit 1

    }

    # zzzzzz..... go away if interrupted

    if (system(sprintf("sleep %d", naptime)) != 0)

        exit 1

    # time to notify!

    command = sprintf("sleep %d", delay)

    for (i = 1; i <= count; i++) {

        print message

        # if sleep command interrupted, go away

        if (system(command) != 0)

            break

    }

    exit 0

}