#!/usr/bin/env perl

use warnings;
use strict;
use 5.10.0;

use utf8;
use open ':encoding(UTF-8)';
use open qw(:std :utf8);

use Time::Piece;
use Time::Seconds;

# We're simulating Unix timestamps here:
my $end   = localtime->epoch;
my $start = $end - (3600);

say "Starting at: $start";

my @bars = qw(_ ▁ ▂ ▃ ▄ ▅ ▆ ▇ █);
my $bin_count = 12;

my $range = $end - $start;
my $bin_width = $range / $bin_count;

my %bins;
for (0..($bin_count - 1)) {
  my $bin_start = $start + ($_ * $bin_width);
  $bins{$bin_start} = 0;
}

# Fake some events:
for (1..200) {
  my $event = $start + int(rand($range));
  for my $bin (keys %bins) {
    if (($event > $bin) && ($event < ($bin + $bin_width))) {
      $bins{$bin}++;
    }
  }
}

# Figure out what the tallest bin is, and map to a unit size.
my $biggest_bin = 0;
foreach my $bin_height (values %bins) {
  if ($bin_height > $biggest_bin) {
    $biggest_bin = $bin_height;
  }
}

# Just some debugging - print bin starts and counts:
foreach my $bin (sort keys %bins) {
  say $bin . " " . $bins{$bin};
}

# Display a bar for each bin:
foreach my $bin (sort keys %bins) {
  my $bar_level = int(($bins{$bin} / $biggest_bin) * (scalar @bars));
  my $bar = ' ';
  if ($bar_level) {
    $bar = $bars[$bar_level - 1];
  }
  print $bar;
}

print "\n";
say "Ending at: $end";