#!/bin/sh

# Shows the date for "fri week" or "mon last" for e.g.

# License: LGPLv2

proc Usage {
    echo "Usage: $(basename $0) mon|tue|... [next]|week|last" >&2
    exit 1
}

test "$Argc" -eq "0" && Usage

setvar day = "$1"
setvar which = "$2"
test -z $which && setvar which = 'next'

case (which) {
week {
    if test $(date +%D) = $(date --date="next $day" +%D) {
        setvar weeks = "+2" #assume we want the next week, not today
    } else {
        setvar weeks = "+1"
    } }
last {
    setvar weeks = '-1'}
next {
    if test $(date +%D) = $(date --date="next $day" +%D) {
        setvar weeks = "+1" #assume we want the next week, not today
    } else {
        setvar weeks = "+0"
    } }
* {
    Usage}
}

date --date="$day $weeks weeks" +%x