#!/usr/bin/env perl

#use Smart::Comments;
use strict;
use warnings;

use YAML::Syck;
use File::Copy;
use List::Util 'sum';

my $cur_file = 't/cur-timer.dat';
my $hist_file = 't/last-timer.dat';

my $cmd = shift || '';
if ($cmd && $cmd ne 'update_hist') {
    die "Command $cmd not recognized.\n";
}

if (!-f $cur_file) {
    die "No $cur_file found. run 'make test' first?\n";
}
if ($cmd eq 'update_hist' or !-f $hist_file) {
    copy($cur_file, $hist_file);
}
my $cur_data = LoadFile($cur_file);
### $cur_data
my $hist_data = LoadFile($hist_file);

sub faster ($$);
sub mean (@);

while (my ($key, $val) =  each %$cur_data) {
    ### $key
    ### $val
    my $len = @$val;
    my $mean = mean(@$val);
    my $hist_val = $hist_data->{$key};
    my $hist_mean = mean(@$hist_val);
    my $percent = faster($mean, $hist_mean);
    my $arrow;
    if ($percent > 0) { $arrow = "FASTER++" }
    elsif ($percent < 0) { $arrow = "SLOWER--" }
    else { $arrow = "" }
    if ($mean < 1) {
        $mean = sprintf("%.02d ms", $mean * 1000);
    } else {
        $mean = sprintf("%.02d s", $mean);
    }
    $mean =~ s/^0+//g;
    print "$key: $mean ($len trials) $percent\% $arrow\n";
}

sub faster ($$) {
    my ($new, $old) = @_;
    my $delta = 1/$new - 1/$old;
    int ($delta / (1/$old) * 100);
}

sub mean (@) {
    my $sum = sum(@_);
    $sum/@_;
}