#!/bin/sh

# A command line Stopwatch

# License: LGPLv2
# Author:
#    http://www.pixelbeat.org/
# Notes:
#    This script starts a few processes per lap, in addition to
#    the shell loop processing, so the assumption is made that
#    this takes an insignificant amount of time compared to
#    the response time of humans (~.1s) (or the keyboard
#    interrupt rate (~.05s)).
#    '?' for splits must be entered twice if characters
#    (erroneously) entered before it (on the same line).
#    '?' since not generating a signal may be slightly delayed
#    on heavily loaded systems.
#    Lap timings on ubuntu may be slightly delayed due to:
#    https://bugs.launchpad.net/bugs/62511
# Changes:
#    V1.0, 23 Aug 2005, Initial release
#    V1.1, 26 Jul 2007, Allow both splits and laps from single invocation.
#                       Only start timer after a key is pressed.
#                       Indicate lap number
#                       Cache programs at startup so there is less error
#                       due to startup delays.
#    V1.2, 01 Aug 2007, Work around `date` commands that don't have nanoseconds.
#                       Use stty to change interrupt keys to space for laps etc.
#                       Ignore other input as it causes problems.
#    V1.3, 01 Aug 2007, Testing release.
#    V1.4, 02 Aug 2007, Various tweaks to get working under ubuntu and Mac OS X.
#    V1.5, 27 Jun 2008, set LANG=C as got vague bug report about it.
#    V1.6, 19 Mar 2015  http://github.com/pixelb/scripts/commits/master/scripts/sw

export LANG=C

ulimit -c 0   #no cores from SIGQUIT
trap '' TSTP  #ignore Ctrl-Z just in case
setglobal save_tty = $[stty -g] && trap "stty $save_tty" EXIT #restore tty on exit
stty quit ' ' #space for laps rather than Ctrl-\
stty eof  '?' #? for splits rather than Ctrl-D
stty -echo    #don't echo input

proc cache_progs {
    stty > /dev/null
    date > /dev/null
    grep . < /dev/null
    shell {echo "import time" | python} 2> /dev/null
    bc < /dev/null
    sed '' < /dev/null
    printf '1' > /dev/null
    /usr/bin/time false !2 > /dev/null
    cat < /dev/null
}
cache_progs #to minimise startup delay

date +%s.%N | grep -qF 'N' && setglobal use_python = '1' #if `date` doesn't have nanoseconds
proc now {
    if test $use_python {
        echo "import time; print time.time()" !2 >/dev/null | python
    } else {
        printf "%.2f" $[date +%s.%N]
    }
}

proc fmt_seconds {
    setglobal seconds = $1
    setglobal mins = $[echo $seconds/60 | bc]
    if test $mins != "0" {
        setglobal seconds = $[echo "$seconds - ($mins*60)" | bc]
        echo "$mins:$seconds"
    } else {
        echo $seconds
    }
}

proc total {
    setglobal end = $[now]
    setglobal total = $[echo "$end - $start" | bc]
    fmt_seconds $total
}

proc stop {
    test $lapped && lap $laptime "display"
    total
    exit
}

proc lap {
    setglobal laptime = $[echo $1 | sed -n 's/.*real[^0-9.]*\(.*\)/\1/p]
    test ! $laptime -o $laptime = "0.00" && return #signals too frequent
    setglobal laptotal = $[echo $laptime+0$laptotal | bc]
    if test $2 = "display" {
        setglobal lapcount = $[echo 0$lapcount+1 | bc]
        setglobal laptime = $[fmt_seconds $laptotal]
        echo $laptime "($lapcount)"
        setglobal lapped = '"true'"
        setglobal laptotal = '"0'"
    }
}

printf "Space for lap | ? for split | Ctrl-C to stop | Space to start..."> !2

while true {
    trap true INT QUIT #set signal handlers
    setglobal laptime = $[/usr/bin/time -p 2>&1 cat!2 > !1 cat >/dev/null]
    setglobal ret = $Status
    trap '' INT QUIT #ignore signals within this script
    if test $ret -eq 1 -o $ret -eq 2 -o $ret -eq 130 { #SIGINT = stop
        test ! $start && do { echo > !2; exit; }
        stop
    } elif test $ret -eq 3 -o $ret -eq 131 { #SIGQUIT = lap
        if test ! $start {
            setglobal start = $[now] || exit 1
            echo > !2
            continue
        }
        lap $laptime "display"
    } else { #eof = split
        test ! $start && continue
        total
        lap $laptime #update laptotal
    }
}