package Catmandu::Fix::Bind::benchmark;

use Catmandu::Sane;

our $VERSION = '1.07';

use Moo;
use Time::HiRes qw(gettimeofday tv_interval);
use namespace::clean;

with 'Catmandu::Fix::Bind';

has output => (is => 'ro', required => 1);
has stats => (is => 'lazy');

sub _build_stats {
    +{};
}

sub bind {
    my ($self, $data, $code, $name) = @_;
    $name = '<undef>' unless defined $name;
    my $t0 = [gettimeofday];
    $data = $code->($data);
    my $elapsed = tv_interval($t0);

    $self->stats->{$name}->{count}   += 1;
    $self->stats->{$name}->{elapsed} += $elapsed;

    $data;
}

sub DESTROY {
    my ($self) = @_;
    local (*OUT);
    open(OUT, '>', $self->output) || return undef;

    printf OUT "%-8.8s\t%-40.40s\t%-8.8s\t%-8.8s\n", 'elapsed', 'command',
        'calls', 'sec/command';
    printf OUT "-" x 100 . "\n";

    for my $key (
        sort {$self->stats->{$b}->{elapsed} cmp $self->stats->{$a}->{elapsed}}
        keys %{$self->stats}
        )
    {
        my $speed
            = $self->stats->{$key}->{elapsed} / $self->stats->{$key}->{count};
        printf OUT "%f\t%-40.40s\t%d times\t%f secs/command\n",
            $self->stats->{$key}->{elapsed}, $key,
            $self->stats->{$key}->{count},   $speed;
    }

    printf OUT "\n\n";
    close(OUT);
}

1;

__END__

=pod

=head1 NAME

Catmandu::Fix::Bind::benchmark - a binder that calculates the execution time of Fix functions

=head1 SYNOPSIS

 do benchmark(output => /dev/stderr)
    foo()
 end

 # will create as side effect computation statistics on the stderr

 elapsed   command              calls    sec/comm
 -------------------------------------------------------------
 0.000006  Catmandu::Fix::foo   1 times  0.000006 secs/command

=head1 DESCRIPTION

The benchmark binder computes all the Fix function plus as side effect
calculates the execution time of all wrapped functions over all input records.

=head1 CONFIGURATION

=head2 output 

Required. The path of a file to which the benchmark statistics will be written.

=head1 SEE ALSO

L<Catmandu::Fix::Bind>

=cut