<?php
/**
 * @copyright Copyright (C) 2010-2023, the Friendica project
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

namespace Friendica\Util;

use Friendica\Core\Config\Capability\IManageConfigValues;
use Friendica\Core\System;
use Psr\Container\ContainerExceptionInterface;
use Psr\Container\ContainerInterface;
use Psr\Container\NotFoundExceptionInterface;
use Psr\Log\LoggerInterface;

/**
 * A class to store profiling data
 * It can handle different logging data for specific functions or global performance measures
 *
 * It stores the data as log entries (@see LoggerInterface)
 */
class Profiler implements ContainerInterface
{
	/**
	 * @var array The global performance array
	 */
	private $performance;
	/**
	 * @var array The function specific callstack
	 */
	private $callstack;
	/**
	 * @var bool True, if the Profiler is enabled
	 */
	private $enabled;
	/**
	 * @var bool True, if the Profiler should measure the whole rendertime including functions
	 */
	private $rendertime;

	private $timestamps = [];

	/**
	 * True, if the Profiler should measure the whole rendertime including functions
	 *
	 * @return bool
	 */
	public function isRendertime(): bool
	{
		return $this->rendertime;
	}

	public function __construct(IManageConfigValues $config)
	{
		$this->enabled    = (bool)$config->get('system', 'profiler') ?? false;
		$this->rendertime = (bool)$config->get('rendertime', 'callstack') ?? false;
		$this->reset();
	}

	/**
	 * Start a profiler recording
	 *
	 * @param string $value
	 *
	 * @return void
	 */
	public function startRecording(string $value)
	{
		if (!$this->enabled) {
			return;
		}

		$this->timestamps[] = ['value' => $value, 'stamp' => microtime(true), 'credit' => 0];
	}

	/**
	 * Stop a profiler recording
	 *
	 * @param string $callstack
	 *
	 * @return void
	 */
	public function stopRecording(string $callstack = '')
	{
		if (!$this->enabled || empty($this->timestamps)) {
			return;
		}

		$timestamp = array_pop($this->timestamps);

		$duration = floatval(microtime(true) - $timestamp['stamp'] - $timestamp['credit']);
		$value    = $timestamp['value'];

		foreach ($this->timestamps as $key => $stamp) {
			$this->timestamps[$key]['credit'] += $duration;
		}

		$callstack = $callstack ?: System::callstack(4, $value == 'rendering' ? 0 : 1);

		if (!isset($this->performance[$value])) {
			$this->performance[$value] = 0;
		}

		$this->performance[$value]     += (float)$duration;
		$this->performance['marktime'] += (float)$duration;

		if (!isset($this->callstack[$value][$callstack])) {
			// Prevent ugly E_NOTICE
			$this->callstack[$value][$callstack] = 0;
		}

		$this->callstack[$value][$callstack] += (float)$duration;
	}

	/**
	 * Saves a timestamp for a value - f.e. a call
	 * Necessary for profiling Friendica
	 *
	 * @param float  $timestamp the Timestamp
	 * @param string $value     A value to profile
	 * @param string $callstack A callstack string, generated if absent
	 *
	 * @return void
	 */
	public function saveTimestamp(float $timestamp, string $value, string $callstack = '')
	{
		if (!$this->enabled) {
			return;
		}

		$callstack = $callstack ?: System::callstack(4, 1);

		$duration = floatval(microtime(true) - $timestamp);

		if (!isset($this->performance[$value])) {
			// Prevent ugly E_NOTICE
			$this->performance[$value] = 0;
		}

		$this->performance[$value]     += (float)$duration;
		$this->performance['marktime'] += (float)$duration;

		if (!isset($this->callstack[$value][$callstack])) {
			// Prevent ugly E_NOTICE
			$this->callstack[$value][$callstack] = 0;
		}

		$this->callstack[$value][$callstack] += (float)$duration;
	}

	/**
	 * Resets the performance and callstack profiling
	 *
	 * @return void
	 */
	public function reset()
	{
		$this->resetPerformance();
		$this->resetCallstack();
	}

	/**
	 * Resets the performance profiling data
	 *
	 * @return void
	 */
	public function resetPerformance()
	{
		$this->performance                   = [];
		$this->performance['start']          = microtime(true);
		$this->performance['ready']          = 0;
		$this->performance['database']       = 0;
		$this->performance['database_write'] = 0;
		$this->performance['cache']          = 0;
		$this->performance['cache_write']    = 0;
		$this->performance['network']        = 0;
		$this->performance['file']           = 0;
		$this->performance['rendering']      = 0;
		$this->performance['session']        = 0;
		$this->performance['marktime']       = microtime(true);
		$this->performance['classcreate']    = 0;
		$this->performance['classinit']      = 0;
		$this->performance['init']           = 0;
		$this->performance['content']        = 0;
	}

	/**
	 * Resets the callstack profiling data
	 *
	 * @return void
	 */
	public function resetCallstack()
	{
		$this->callstack                   = [];
		$this->callstack['database']       = [];
		$this->callstack['database_write'] = [];
		$this->callstack['cache']          = [];
		$this->callstack['cache_write']    = [];
		$this->callstack['network']        = [];
		$this->callstack['file']           = [];
		$this->callstack['rendering']      = [];
		$this->callstack['session']        = [];
	}

	/**
	 * Returns the rendertime string
	 *
	 * @param float $limit Minimal limit for displaying the execution duration
	 *
	 * @return string the rendertime
	 */
	public function getRendertimeString(float $limit = 0): string
	{
		$output = '';

		if (!$this->enabled || !$this->rendertime) {
			return $output;
		}

		if (isset($this->callstack['database'])) {
			$output .= "\nDatabase Read:\n";
			foreach ($this->callstack['database'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		if (isset($this->callstack['database_write'])) {
			$output .= "\nDatabase Write:\n";
			foreach ($this->callstack['database_write'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		if (isset($this->callstack['cache'])) {
			$output .= "\nCache Read:\n";
			foreach ($this->callstack['cache'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		if (isset($this->callstack['cache_write'])) {
			$output .= "\nCache Write:\n";
			foreach ($this->callstack['cache_write'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		if (isset($this->callstack['network'])) {
			$output .= "\nNetwork:\n";
			foreach ($this->callstack['network'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		if (isset($this->callstack['rendering'])) {
			$output .= "\nRendering:\n";
			foreach ($this->callstack['rendering'] as $func => $time) {
				$time = round($time, 3);
				if ($time > $limit) {
					$output .= $func . ': ' . $time . "\n";
				}
			}
		}

		return $output;
	}

	/**
	 * Save the current profiling data to a log entry
	 *
	 * @param LoggerInterface $logger  The logger to save the current log
	 * @param string          $message Additional message for the log
	 *
	 * @return void
	 */
	public function saveLog(LoggerInterface $logger, string $message = '')
	{
		$duration = microtime(true) - $this->get('start');
		$logger->info(
			$message,
			[
				'action'         => 'profiling',
				'database_read'  => round($this->get('database') - $this->get('database_write'), 3),
				'database_write' => round($this->get('database_write'), 3),
				'cache_read'     => round($this->get('cache'), 3),
				'cache_write'    => round($this->get('cache_write'), 3),
				'network_io'     => round($this->get('network'), 2),
				'file_io'        => round($this->get('file'), 2),
				'other_io'       => round($duration - ($this->get('database')
													   + $this->get('cache') + $this->get('cache_write')
													   + $this->get('network') + $this->get('file')), 2),
				'total'          => round($duration, 2)
			]
		);

		if ($this->isRendertime()) {
			$output = $this->getRendertimeString();
			$logger->info($message . ": " . $output, ['action' => 'profiling']);
		}
	}

	/**
	 * Finds an entry of the container by its identifier and returns it.
	 *
	 * @param string $id Identifier of the entry to look for.
	 *
	 * @return float Entry.
	 * @throws ContainerExceptionInterface Error while retrieving the entry.
	 *
	 * @throws NotFoundExceptionInterface  No entry was found for **this** identifier.
	 */
	public function get(string $id): float
	{
		if (!$this->has($id)) {
			return 0;
		} else {
			return $this->performance[$id];
		}
	}

	public function set($timestamp, string $id)
	{
		$this->performance[$id] = $timestamp;
	}

	/**
	 * Returns true if the container can return an entry for the given identifier.
	 * Returns false otherwise.
	 *
	 * `has($id)` returning true does not mean that `get($id)` will not throw an exception.
	 * It does however mean that `get($id)` will not throw a `NotFoundExceptionInterface`.
	 *
	 * @param string $id Identifier of the entry to look for.
	 *
	 * @return bool
	 */
	public function has(string $id): bool
	{
		return isset($this->performance[$id]);
	}
}