sfmatrix - simulates the display from "The Matrix"

sfmatrix.php

#!/usr/bin/env php
<?php

require __DIR__.'/vendor/autoload.php';

use Symfony\Component\Console\Cursor;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\SingleCommandApplication;
use Symfony\Component\Console\Terminal;

define('SPEED', 25000);

(new SingleCommandApplication())
    ->setCode(function (InputInterface $input, OutputInterface $output) {
        $terminal = new Terminal();
        $width = $terminal->getWidth();
        $height = $terminal->getHeight();
        $cursor = new Cursor($output);
        $cursor->hide();
        $cursor->clearScreen();
       
        // Make background black
        for ($row = 0; $row < $height; $row++) {
            for ($col = 0; $col < $width; $col++) {
                $cursor->moveToPosition($col, $row);
                $output->write('<bg=#000000> </>');
            }
        }

        // Keep used columns locked to avoid overwrite
        $lockedX = [];
        $traces = [];

        while (true) {
            // Maintain a certain amount of active traces
            while (count($traces) < round($width * 0.7)) {
                // Generate start coordinates
                $x = array_rand(array_diff(range(0, $width - 1), $lockedX));
                $lockedX[] = $x;
                $y = rand(0, $height - 5);

                // Generate random code for the trace
                $code = [];
                $length = rand(5, round(($height - $y - 1) * 0.7));
                for ($i = 0; $i < $length; $i++) {
                    $code[] = chr(rand(33, 49));
                    // $code[] = mb_chr(rand(12448, 12543));
                }
                
                $traces[] = new Trace(
                    $output,
                    $cursor,
                    $x,
                    $y,
                    $code
                );
            }

            foreach ($traces as $i => $trace) {
                $trace->write();
                
                // Cleanup erased traces
                if (! $trace->visible()) {
                    unset($lockedX[array_search($trace->x(), $lockedX)]);
                    unset($traces[$i]);
                }
            }

            usleep(SPEED);
        }

        return 0;
    })->run();

class Trace
{
    private OutputInterface $output;
    private Cursor $cursor;

    private int $x;
    private int $y;

    private array $code;
    private int $lenght;
    private int $offset;

    public function __construct(OutputInterface $output, Cursor $cursor, int $x, int $y, array $code)
    {
        $this->output = $output;
        $this->cursor = $cursor;

        $this->x = $x;
        $this->y = $y;
        $this->code = $code;
        $this->length = count($code);

        $this->offset = 0;
    }

    public function write(): void
    {
        $this->offset++;
        
        for ($y = $this->y, $code = 0; $y < $this->y + $this->offset; $y++, $code++) {
            $this->cursor->moveToPosition($this->x, $y);
            
            // Code is printed, erase first character
            if ($code == $this->offset - $this->length) {
                $this->output->write('<bg=#000000> </>');
                continue;
            }

            // Code is printed
            if ($code >= count($this->code)) {
                continue;
            }

            // Print previous character green
            if ($code === $this->offset - 2) {
                $this->output->write('<fg=#00ff00;bg=#000000>'.$this->code[$code].'</>');
                continue;
            }

            // Print first character white
            if ($code === $this->offset - 1) {
                $this->output->write('<fg=#ffffff;bg=#000000>'.$this->code[$code].'</>');
            }
        }
    }
    
    public function x(): int
    {
        return $this->x;
    }

    public function visible(): bool
    {
        return $this->length > $this->offset - $this->length;
    }
}