<?php

declare(strict_types=1);

/**
 * This file is part of CodeIgniter 4 framework.
 *
 * (c) CodeIgniter Foundation <admin@codeigniter.com>
 *
 * For the full copyright and license information, please view
 * the LICENSE file that was distributed with this source code.
 */

namespace CodeIgniter\Debug;

use Closure;

/**
 * Iterator for debugging.
 */
class Iterator
{
 /**
 * Stores the tests that we are to run.
 *
 * @var array
 */
 protected $tests = [];

 /**
 * Stores the results of each of the tests.
 *
 * @var array
 */
 protected $results = [];

 /**
 * Adds a test to run.
 *
 * Tests are simply closures that the user can define any sequence of
 * things to happen during the test.
 *
 * @param Closure(): mixed $closure
 *
 * @return $this
 */
 public function add(string $name, Closure $closure)
 {
 $name = strtolower($name);

 $this->tests[$name] = $closure;

 return $this;
 }

 /**
 * Runs through all of the tests that have been added, recording
 * time to execute the desired number of iterations, and the approximate
 * memory usage used during those iterations.
 *
 * @return string|null
 */
 public function run(int $iterations = 1000, bool $output = true)
 {
 foreach ($this->tests as $name => $test) {
 // clear memory before start
 gc_collect_cycles();

 $start = microtime(true);
 $startMem = $maxMemory = memory_get_usage(true);

 for ($i = 0; $i < $iterations; $i++) {
 $result = $test();
 $maxMemory = max($maxMemory, memory_get_usage(true));

 unset($result);
 }

 $this->results[$name] = [
 'time' => microtime(true) - $start,
 'memory' => $maxMemory - $startMem,
 'n' => $iterations,
 ];
 }

 if ($output) {
 return $this->getReport();
 }

 return null;
 }

 /**
 * Get results.
 */
 public function getReport(): string
 {
 if ($this->results === []) {
 return 'No results to display.';
 }

 helper('number');

 // Template
 $tpl = '<table>
			<thead>
				<tr>
					<td>Test</td>
					<td>Time</td>
					<td>Memory</td>
				</tr>
			</thead>
			<tbody>
				{rows}
			</tbody>
		</table>';

 $rows = '';

 foreach ($this->results as $name => $result) {
 $memory = number_to_size($result['memory'], 4);

 $rows .= "<tr>
				<td>{$name}</td>
				<td>" . number_format($result['time'], 4) . "</td>
				<td>{$memory}</td>
			</tr>";
 }

 $tpl = str_replace('{rows}', $rows, $tpl);

 return $tpl . '<br/>';
 }
}