#!/usr/bin/perl --
use strict;
use warnings;


{
    my $sentinel = expireAfter( 1, 9 );
    print "begin ", scalar(gmtime),"\n";
    while( $sentinel->() ){
        print "loop ", scalar(gmtime),"\n";
    }
    print "end ", scalar(gmtime),"\n";
}
{
    my $sentinel = expireAfter( 1, 5 );
    print "begin ", scalar(gmtime),"\n";
    while( $sentinel->() ){
        print "loop ", scalar(gmtime),"\n";
    }
    print "end ", scalar(gmtime),"\n";
}

#~ use constant DEBUG => 1 || !!$ENV{PERL_MYAPP_DEBUG};
use constant DEBUG => 0 || !!$ENV{PERL_MYAPP_DEBUG};

=head2 C<<< checkEveryExpireAfter( $every, $after ) >>>

check $every seconds, if it hasn't been $every seconds yet, wait until it has

stop checking $after seconds have elapsed


    checkExpire( $every, $after )
    intervalExpire( $every, $after )
    afterExpire( $every, $expire )
    everyUntil( $second, $expire )
    breatheUntil( $second, $expire )
    

=cut

sub expireAfter {
    my( $ten, $after ) = @_;
    my $lasttime = time;
    my $expire   = $lasttime + $after;
    DEBUG and warn "## eA ## ten($ten)after($after)lasttime($lasttime)expire($expire)";
    return sub {
        my $newtime = time;
        my $diff    = $newtime - $lasttime;
        if( $expire < $newtime ){
            DEBUG and warn "## eA ## expired ( $expire < $newtime )";
            return !!0;
        } elsif( $diff < $ten ){
            DEBUG and warn "## eA ## sleep ( $diff < $ten )";
            sleep abs( $diff - $ten );
        }
        $lasttime = time;
        if( $expire < $lasttime ){
            DEBUG and warn "## eA ## expired ( $expire > $lasttime )";
            return !!0;
        } else {
            DEBUG and warn "## eA ## loop ( $expire > $lasttime )";
            return !!1;
        }
    };
}

sub expireAfterGood {
    my( $ten, $after ) = @_;
    my $lasttime = time;
    my $expire   = $lasttime + $after;
    return sub {
        my $newtime = time;
        my $diff    = $newtime - $lasttime;
        if( $expire < $newtime ){
            warn "( $expire < $newtime )";
            return !!0;
        } elsif( $diff < $ten ){
            warn "expired ( $diff < $ten )";
            sleep abs( $diff - $ten );
        }
        $lasttime = time;
        if( $expire < $lasttime ){
            warn "expired ( $expire > $lasttime )";
            return !!0;
        } else {
            return !!1;
        }
    };
}

sub expireAfterBuggy {
    my( $ten, $after ) = @_;
    my $lasttime = time;
    my $expire   = $lasttime + $after;
    return sub {
        my $newtime = time;
        my $diff    = $newtime - $lasttime;
        if( $expire > $lasttime ){
            warn "( $expire > $lasttime )";
            return !!0;
        } elsif( $diff < $ten ){
            warn "expired ( $diff < $ten )";
            sleep abs( $diff - $ten );
        }
        $lasttime = time;
        if( $expire > $lasttime ){
            warn "expired ( $expire > $lasttime )";
            return !!0;
        } else {
            return !!1;
        }
    };
}