#!/usr/bin/perl

use lib '..';
use Memoize;
use Time::HiRes 'time';
my $DEBUG = 0;

my $n = 0;
$| = 1;

if (-e '.fast') {
  print "1..0\n";
  exit 0;
}

# Perhaps nobody will notice if we don't say anything
# print "# Warning: I'm testing the timed expiration policy.\n# This will take about thirty seconds.\n";

print "1..15\n";
$| = 1;

++$n; print "ok $n\n";

require Memoize::Expire;
++$n; print "ok $n\n";

sub close_enough {
#  print "Close enough? @_[0,1]\n";
  abs($_[0] - $_[1]) <= 1;
}

my $t0;
sub start_timer {
  $t0 = time;
  $DEBUG and print "# $t0\n";
}

sub wait_until {
  my $until = shift();
  my $diff = $until - (time() - $t0);
  $DEBUG and print "# until $until; diff = $diff\n";
  return if $diff <= 0;
  select undef, undef, undef, $diff;
}

sub now {
#  print "NOW: @_ ", time(), "\n";
  time;
}

tie my %cache => 'Memoize::Expire', LIFETIME => 8;
memoize 'now',
    SCALAR_CACHE => [HASH => \%cache ],
    LIST_CACHE => 'FAULT'
    ;

++$n; print "ok $n\n";


# T
start_timer();
for (1,2,3) {
  $when{$_} = now($_);
  ++$n;
  print "not " unless close_enough($when{$_}, time());
  print "ok $n\n";
  sleep 3 if $_ < 3;
  $DEBUG and print "# ", time()-$t0, "\n";
}
# values will now expire at T=8, 11, 14
# it is now T=6

# T+6
for (1,2,3) {
  $again{$_} = now($_); # Should be the same as before, because of memoization
}

# T+6
foreach (1,2,3) {
  ++$n;
  print "not " unless close_enough($when{$_}, $again{$_});
  print "ok $n\n";
}

wait_until(9.5);  # now(1) expires
print "not " unless close_enough(time, $again{1} = now(1));
++$n; print "ok $n\n";

# T+9.5
foreach (2,3) {			# Should not have expired yet.
  ++$n;
  print "not " unless close_enough(scalar(now($_)), $again{$_});
  print "ok $n\n";
}

wait_until(12.5);  # now(2) expires

# T+12.5
print "not " unless close_enough(time, $again{2} = now(2));
++$n; print "ok $n\n";

# T+12.5
foreach (1,3) {  # 1 is good again because it was recomputed after it expired
  ++$n;
  print "not " unless close_enough(scalar(now($_)), $again{$_});
  print "ok $n\n";
}