#!/usr/bin/env perl
use strict;
use Data::Dumper;
use Time::HiRes qw(gettimeofday tv_interval);

my $points = shift @ARGV;

my @points = read_points($points);

my $start = [gettimeofday];
my ($x, $y) = shortest_distance(@points);
my $end = [gettimeofday];

report($x, $y, $points, tv_interval($start, $end));

#This is the main loop, everything else is fluff.
sub shortest_distance {
    my @points = @_;
    my $points = @points;

    my $min_distance = 4294967296;
    my @min;

    for (my $i = 0 ; $i < $points ; $i++) {
        for (my $j = 0 ; $j < $points ; $j++) {
				
				
				#this does not need to check the same point
				# skip where j==i
				
				
            my $d = distance($points[$i], $points[$j]); # sqrt(a2 + b2) not necessary... just smallest (diff x * diff y) is needed, then do sqrt(a2+b2)
				
				#use a hash.... and insert x coordinates that are the same...
				# push(@{ $foo{$x} }, $y);... but do you find the distance on insert?
				
				# this doesn't need to check if d>0, duplicate coordinates are treated as one
            if ($d > 0 && $d <= $min_distance) {
                $min_distance = $d;
                @min = ($i, $j);
            }
        }
    }
    return @min;
}

sub distance {
    my ($a, $b) = @_;
    my $d =
      sqrt((abs($a->[0] - $b->[0])**2) + (abs($a->[1] - $b->[1])**2));
}

sub report {
    my ($x, $y, $points, $time) = @_;
    print "The minimum distance is between point $x and $y\n";
    print "$x: $points[$x][0], $points[$x][1]\n";
    print "$y: $points[$y][0], $points[$y][1]\n";
    print "Distance: ", distance($points[$x], $points[$y]), "\n";
    print "Took $time seconds\n";
    print "At a rate of ", $time/$points ," sec/point\n";
}

use constant MAX => 255;

sub read_points {
    my $cnt = shift;
    my @p;
    
    open (my $p, ">", "points.txt");

    my $i = 0;
    while ($i < $cnt) {
        my $x = int(rand(MAX));
        my $y = int(rand(MAX));
        push @p, [$x, $y];
        print $p  "$i: $x, $y\n";
        $i++;
    }
    print "We have ", scalar(@p), " points\n";
    close($p);
    return @p;
}