<?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 CodeIgniter\Exceptions\RuntimeException;

/**
 * Class Timer
 *
 * Provides a simple way to measure the amount of time
 * that elapses between two points.
 *
 * @see \CodeIgniter\Debug\TimerTest
 */
class Timer
{
    /**
     * List of all timers.
     *
     * @var array
     */
    protected $timers = [];

    /**
     * Starts a timer running.
     *
     * Multiple calls can be made to this method so that several
     * execution points can be measured.
     *
     * @param string     $name The name of this timer.
     * @param float|null $time Allows user to provide time.
     *
     * @return Timer
     */
    public function start(string $name, ?float $time = null)
    {
        $this->timers[strtolower($name)] = [
            'start' => ! empty($time) ? $time : microtime(true),
            'end'   => null,
        ];

        return $this;
    }

    /**
     * Stops a running timer.
     *
     * If the timer is not stopped before the timers() method is called,
     * it will be automatically stopped at that point.
     *
     * @param string $name The name of this timer.
     *
     * @return Timer
     */
    public function stop(string $name)
    {
        $name = strtolower($name);

        if (empty($this->timers[$name])) {
            throw new RuntimeException('Cannot stop timer: invalid name given.');
        }

        $this->timers[$name]['end'] = microtime(true);

        return $this;
    }

    /**
     * Returns the duration of a recorded timer.
     *
     * @param string $name     The name of the timer.
     * @param int    $decimals Number of decimal places.
     *
     * @return float|null Returns null if timer does not exist by that name.
     *                    Returns a float representing the number of
     *                    seconds elapsed while that timer was running.
     */
    public function getElapsedTime(string $name, int $decimals = 4)
    {
        $name = strtolower($name);

        if (empty($this->timers[$name])) {
            return null;
        }

        $timer = $this->timers[$name];

        if (empty($timer['end'])) {
            $timer['end'] = microtime(true);
        }

        return (float) number_format($timer['end'] - $timer['start'], $decimals, '.', '');
    }

    /**
     * Returns the array of timers, with the duration pre-calculated for you.
     *
     * @param int $decimals Number of decimal places
     */
    public function getTimers(int $decimals = 4): array
    {
        $timers = $this->timers;

        foreach ($timers as &$timer) {
            if (empty($timer['end'])) {
                $timer['end'] = microtime(true);
            }

            $timer['duration'] = (float) number_format($timer['end'] - $timer['start'], $decimals);
        }

        return $timers;
    }

    /**
     * Checks whether or not a timer with the specified name exists.
     */
    public function has(string $name): bool
    {
        return array_key_exists(strtolower($name), $this->timers);
    }

    /**
     * Executes callable and measures its time.
     * Returns its return value if any.
     *
     * @param string            $name     The name of the timer
     * @param callable(): mixed $callable callable to be executed
     *
     * @return mixed
     */
    public function record(string $name, callable $callable)
    {
        $this->start($name);
        $returnValue = $callable();
        $this->stop($name);

        return $returnValue;
    }
}
