<?php
/**
 * @package   akeebabackup
 * @copyright Copyright (c)2006-2022 Nicholas K. Dionysopoulos / Akeeba Ltd
 * @license   GNU General Public License version 3, or later
 */

namespace Akeeba\Component\AkeebaBackup\Administrator\Model;

defined('_JEXEC') || die;

use Akeeba\Component\AkeebaBackup\Administrator\Mixin\ModelChmodTrait;
use Akeeba\Engine\Factory;
use Akeeba\Engine\Platform;
use Exception;
use Joomla\CMS\Factory as JoomlaFactory;
use Joomla\CMS\MVC\Model\BaseDatabaseModel;

#[\AllowDynamicProperties]
class ConfigurationwizardModel extends BaseDatabaseModel
{
	use ModelChmodTrait;

	/**
	 * Method to get state variables. Uses application input if the state is not set.
	 *
	 * @param   null   $property  Optional parameter name
	 * @param   mixed  $default   Optional default value
	 *
	 * @return  mixed  The property where specified, the state object where omitted
	 *
	 * @throws Exception
	 * @since   4.0.0
	 */
	public function getState($property = null, $default = null)
	{
		try
		{
			$default = JoomlaFactory::getApplication()->input
				->get($property, $default, is_array($default) ? 'array' : 'raw');
		}
		catch (Exception $e)
		{
		}

		return parent::getState($property, $default);
	}

	/**
	 * Attempts to automatically figure out where the output and temporary directories should point, adjusting their
	 * permissions should it be necessary.
	 *
	 * @param   bool  $dontRecurse  Used internally. Always skip this parameter when calling this method.
	 *
	 * @return  bool  True if we could fix the directories
	 * @throws  Exception
	 */
	public function autofixDirectories(bool $dontRecurse = false): bool
	{
		// Get the output directory, translated
		$engineConfig    = Factory::getConfiguration();
		$outputDirectory = $engineConfig->get('akeeba.basic.output_directory', '');
		$fixOut          = true;

		// If no output directory is specified set it the default output and retry.
		if (empty($outputDirectory) && !$dontRecurse)
		{
			/** @var ConfigurationModel $model */
			$model = $this->getMVCFactory()->createModel('Configuration', 'Administrator');

			$model->setState('engineconfig', [
				'akeeba.basic.output_directory' => '[DEFAULT_OUTPUT]',
			]);
			$model->saveEngineConfig();

			return $this->autofixDirectories(true);
		}

		// Is the folder writeable?
		if (is_dir($outputDirectory))
		{
			$filename = $outputDirectory . '/test.dat';
			$fixOut   = !@file_put_contents($filename, 'test');

			if (!$fixOut)
			{
				// Directory writable, remove the temp file
				@unlink($filename);
			}
		}

		// Do I need to change the permissions?
		if ($fixOut)
		{
			// Try to chmod the directory
			$this->chmod($outputDirectory, 511);

			// Repeat the test
			$filename = $outputDirectory . '/test.dat';
			$fixOut   = !@file_put_contents($filename, 'test');

			if (!$fixOut)
			{
				// Directory writable, remove the temp file
				@unlink($filename);
			}
		}

		/**
		 * If we reached this point after recursion, we can't fix the permissions of the default backup output folder.
		 * The user has to manually select a writeable backup output directory (or make the default otuput writeable).
		 */
		if ($fixOut && $dontRecurse)
		{
			return false;
		}

		/**
		 * Write the output folder through the Configuration model. This ensures that:
		 *
		 * - we are not trying to use the site's root as the output folder.
		 * - the output folder saved in the database contains an abstracted representation of the folder, using path
		 *   variables instead of absolute filesystem folders.
		 *
		 * @var ConfigurationModel $model
		 */

		$model = $this->getMVCFactory()->createModel('Configuration', 'Administrator');

		// Do I have to fall back to the default output directory?
		$outputDirectory = $fixOut ? '[DEFAULT_OUTPUT]' : $outputDirectory;

		$model->setState('engineconfig', [
			'akeeba.basic.output_directory' => $outputDirectory,
		]);
		$model->saveEngineConfig();

		/**
		 * If we had to revert to the default output we will run ourselves again to make sure that the default backup
		 * output folder is, in fact, writeable.
		 */
		if ($fixOut)
		{
			return $this->autofixDirectories(true);
		}

		return true;
	}

	/**
	 * Creates a temporary file of a specific size
	 *
	 * @param   int          $blocks         How many 128Kb blocks to write. Common values: 1, 2, 4, 16, 40, 80, 81
	 * @param   string|null  $tempDirectory  Asbolute path to the temporary directory
	 *
	 * @return  bool  TRUE on success
	 */
	public function createTempFile(int $blocks = 1, ?string $tempDirectory = null): bool
	{
		if (empty($tempDirectory))
		{
			$aeconfig      = Factory::getConfiguration();
			$tempDirectory = $aeconfig->get('akeeba.basic.output_directory', '');
		}

		$sixtyfourBytes = '012345678901234567890123456789012345678901234567890123456789ABCD';
		$oneKilo        = '';
		$oneBlock       = '';

		for ($i = 0; $i < 16; $i++)
		{
			$oneKilo .= $sixtyfourBytes;
		}

		for ($i = 0; $i < 128; $i++)
		{
			$oneBlock .= $oneKilo;
		}

		$filename = tempnam($tempDirectory, 'confwiz');
		@unlink($filename);

		$fp = @fopen($filename, 'w');

		if ($fp !== false)
		{
			for ($i = 0; $i < $blocks; $i++)
			{
				if (!@fwrite($fp, $oneBlock))
				{
					@fclose($fp);
					@unlink($filename);

					return false;
				}
			}

			@fclose($fp);
			@unlink($filename);
		}
		else
		{
			return false;
		}

		return true;
	}

	/**
	 * Sleeps for a given amount of time. Returns false if the sleep time requested is over the maximum execution time.
	 *
	 * @param   int  $secondsDelay  Seconds to sleep
	 *
	 * @return  bool  FALSE if we cannot sleep that long
	 */
	public function doNothing(int $secondsDelay = 1): bool
	{
		// Try to get the maximum execution time and PHP memory limit
		if (function_exists('ini_get'))
		{
			$maxexec  = ini_get("max_execution_time");
			$memlimit = ini_get("memory_limit");
		}
		else
		{
			$maxexec  = 14;
			$memlimit = 16777216;
		}

		// Unknown time limit; suppose 10s
		if (!is_numeric($maxexec) || ($maxexec == 0))
		{
			$maxexec = 10;
		}

		// Some servers report silly values, i.e. 30000, which Do Not Work™ :(
		if ($maxexec > 180)
		{
			$maxexec = 10;
		}

		// Sometimes memlimit comes with the M or K suffixes. Parse them.
		if (is_string($memlimit))
		{
			$memlimit = strtoupper(trim(str_replace(' ', '', $memlimit)));

			if (substr($memlimit, -1) == 'K')
			{
				$memlimit = 1024 * substr($memlimit, 0, -1);
			}
			elseif (substr($memlimit, -1) == 'M')
			{
				$memlimit = 1024 * 1024 * substr($memlimit, 0, -1);
			}
			elseif (substr($memlimit, -1) == 'G')
			{
				$memlimit = 1024 * 1024 * 1024 * substr($memlimit, 0, -1);
			}
		}

		// Unknown limit; suppose 16M
		if (!is_numeric($memlimit) || ($memlimit === 0))
		{
			$memlimit = 16777216;
		}

		// No limit; suppose 128M
		if ($memlimit === -1)
		{
			$memlimit = 134217728;
		}

		// Get the current memory usage (or assume one if the metric is not available)
		if (function_exists('memory_get_usage'))
		{
			$usedram = memory_get_usage();
		}
		else
		{
			$usedram = 7340032; // Suppose 7M of RAM usage if the metric isn't available;
		}

		// If we have less than 12M of RAM left, we have to limit ourselves to 6 seconds of
		// total execution time (emperical value!) to avoid deadly memory outages
		if (($memlimit - $usedram) < 12582912)
		{
			$maxexec = 5;
		}

		// If the requested delay is over the $maxexec limit (minus one second
		// for application initialization), return false
		if ($secondsDelay > ($maxexec - 1))
		{
			return false;
		}

		// And now, run the silly loop to simulate the CPU usage pattern during backup
		$start = microtime(true);
		$loop  = true;

		while ($loop)
		{
			// Waste some CPU power...
			for ($i = 1; $i < 1000; $i++)
			{
				$j = exp(($i * $i / 123 * 864) >> 2);

				unset($j);
			}

			// ... then sleep for a millisec
			usleep(1000);

			// Are we done yet?
			$end = microtime(true);

			if (($end - $start) >= $secondsDelay)
			{
				$loop = false;
			}
		}

		return true;
	}

	/**
	 * This method will analyze your database tables and try to figure out the optimal batch row count value so that its
	 * SELECT doesn't return excessive amounts of data. The only drawback is that it only accounts for the core tables,
	 * but that is usually a good metric.
	 *
	 * @return  void
	 */
	public function analyzeDatabase(): void
	{
		$memlimit = 16777216;

		// Try to get the PHP memory limit
		if (function_exists('ini_get'))
		{
			$memlimit = ini_get("memory_limit");
		}

		if (!is_numeric($memlimit) || ($memlimit === 0))
		{
			$memlimit = 16777216; // Unknown limit; suppose 16M
		}

		if ($memlimit === -1)
		{
			$memlimit = 134217728; // No limit; suppose 128M
		}

		// Get the current memory usage (or assume one if the metric is not available)
		$usedram = 7340032;

		if (function_exists('memory_get_usage'))
		{
			$usedram = memory_get_usage();
		}

		// How much RAM can I spare? It's the max memory minus the current memory usage and an extra
		// 5Mb to cater for Akeeba Engine's peak memory usage
		$max_mem_usage = $usedram + 5242880;
		$ram_allowance = $memlimit - $max_mem_usage;

		// If the RAM allowance is too low, assume 2Mb (emperical value)
		if ($ram_allowance < 2097152)
		{
			$ram_allowance = 2097152;
		}

		// If SHOW TABLE STATUS is not supported this is a safe-ish value.
		$rowCount = 100;

		// Get the table statistics
		$db = $this->getDatabase();

		if (stripos($db->getName(), 'mysql') !== false)
		{
			// The table analyzer only works with MySQL
			$db->setQuery("SHOW TABLE STATUS");

			try
			{
				$metrics = $db->loadAssocList();
			}
			catch (Exception $exc)
			{
				$metrics = null;
			}

			// SHOW TABLE STATUS is supported.
			if (!empty($metrics))
			{
				$rowCount = 1000; // Start with the default value

				foreach ($metrics as $table)
				{
					// Get row count and average row length
					$rows    = $table['Rows'];
					$avg_len = $table['Avg_row_length'];

					// Calculate RAM usage with current settings
					$max_rows        = min($rows, $rowCount);
					$max_ram_current = $max_rows * $avg_len;

					if ($max_ram_current > $ram_allowance)
					{
						// Hm... over the allowance. Let's try to find a sweet spot.
						$max_rows = (int) ($ram_allowance / $avg_len);
						// Quantize to multiple of 10 rows
						$max_rows = 10 * floor($max_rows / 10);

						// Can't really go below 10 rows / batch
						if ($max_rows < 10)
						{
							$max_rows = 10;
						}

						// If the new setting is less than the current $rowCount, use the new setting
						if ($rowCount > $max_rows)
						{
							$rowCount = $max_rows;
						}
					}
				}
			}
		}

		$profile_id = Platform::getInstance()->get_active_profile();
		$config     = Factory::getConfiguration();

		// Use the correct database dump engine (only 'native' is currently supported)
		$config->set('akeeba.advanced.dump_engine', 'native');

		// Save the row count per batch
		$config->set('engine.dump.common.batchsize', $rowCount);

		// Enable SQL file splitting - default is 512K unless the part_size is less than that!
		$splitSize = 524288;
		$partSize  = $config->get('engine.archiver.common.part_size', 0);

		if (($partSize < $splitSize) && !empty($partSize))
		{
			$splitSize = $partSize;
		}

		$config->set('engine.dump.common.splitsize', $splitSize);

		// Enable extended INSERTs
		$config->set('engine.dump.common.extended_inserts', '1');

		// Determine optimal packet size (must be at most two fifths of the split size and no more than 256K)
		$packet_size = (int) $splitSize * 0.4;

		if ($packet_size > 262144)
		{
			$packet_size = 262144;
		}

		$config->set('engine.dump.common.packet_size', $packet_size);

		// Enable the native dump engine
		$config->set('akeeba.advanced.dump_engine', 'native');

		Platform::getInstance()->save_configuration($profile_id);
	}

	/**
	 * Executes the action requested through AJAX
	 *
	 * @return  bool
	 * @throws  Exception
	 *
	 * @noinspection PhpUnused
	 */
	public function runAjax(): bool
	{
		// Only allowed actions
		$allowedActions = [
			'ping', 'minexec', 'applyminexec', 'directories', 'database', 'maxexec', 'applymaxexec', 'partsize',
		];

		// Get the requested action from the model state
		$action = $this->getState('act');

		$result = false;

		if (in_array($action, $allowedActions) && method_exists($this, $action))
		{
			$result = call_user_func([$this, $action]);
		}

		return $result;
	}

	/**
	 * Creates a dummy file of a given size. Remember to give the filesize query parameter in bytes!
	 *
	 * @return  bool
	 * @throws  Exception
	 */
	public function partsize(): bool
	{
		$timer  = Factory::getTimer();
		$blocks = JoomlaFactory::getApplication()->input->getInt('blocks', 1);

		$result = $this->createTempFile($blocks);

		if ($result)
		{
			// Save the setting
			if ($blocks > 200)
			{
				$blocks = 16383; // Over 25Mb = 2Gb minus 128Kb limit (safe setting for PHP not running on 64-bit Linux)
			}

			$profile_id = Platform::getInstance()->get_active_profile();
			$config     = Factory::getConfiguration();
			$config->set('engine.archiver.common.part_size', $blocks * 128 * 1024);
			Platform::getInstance()->save_configuration($profile_id);
		}

		// Enforce the min exec time
		$timer->enforce_min_exec_time(false);

		return $result;
	}

	/**
	 * Pings the configuration wizard process and marks the current profile as configured
	 *
	 * @return  bool  TRUE, always
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function ping(): bool
	{
		// Get the profile ID
		$profile_id = Platform::getInstance()->get_active_profile();

		// Set the embedded installer to the default ANGIE installer
		$engineConfig = Factory::getConfiguration();
		$engineConfig->set('akeeba.advanced.embedded_installer', 'angie');

		// And mark this profile as already configured
		$engineConfig->set('akeeba.flag.confwiz', 1);

		Platform::getInstance()->save_configuration($profile_id);

		return true;
	}

	/**
	 * Try different values of minimum execution time
	 *
	 * @return  bool  TRUE, always
	 * @throws  Exception
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function minexec(): bool
	{
		$seconds = JoomlaFactory::getApplication()->input
			->get('seconds', '0.5', 'float');

		if ($seconds < 1)
		{
			usleep($seconds * 1000000);
		}
		else
		{
			sleep($seconds);
		}

		return true;
	}

	/**
	 * Saves the AJAX preference and the minimum execution time
	 *
	 * @return  bool  TRUE, always
	 * @throws  Exception
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function applyminexec(): bool
	{
		// Get the user parameters
		$minexec = JoomlaFactory::getApplication()->input
			->get('minexec', 2.0, 'float');

		// Save the settings
		$profile_id   = Platform::getInstance()->get_active_profile();
		$engineConfig = Factory::getConfiguration();
		$engineConfig->set('akeeba.tuning.min_exec_time', $minexec * 1000);
		Platform::getInstance()->save_configuration($profile_id);

		// Enforce the min exec time
		$timer = Factory::getTimer();
		$timer->enforce_min_exec_time(false);

		// Done!
		return true;
	}

	/**
	 * Try to make the directories writable or provide a set of writable directories
	 *
	 * @return  bool  TRUE if we coud fix the permissions of the directories
	 * @throws  Exception
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function directories(): bool
	{
		$timer  = Factory::getTimer();
		$result = $this->autofixDirectories();
		$timer->enforce_min_exec_time(false);

		return $result;
	}

	/**
	 * Analyze the database and apply optimized database dump settings
	 *
	 * @return  bool  TRUE if we were successful
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function database(): bool
	{
		$timer = Factory::getTimer();
		$this->analyzeDatabase();
		$timer->enforce_min_exec_time(false);

		return true;
	}

	/**
	 * Try to apply a specific maximum execution time setting
	 *
	 * @return  bool
	 * @throws  Exception
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function maxexec(): bool
	{
		$seconds = JoomlaFactory::getApplication()->input
			->get('seconds', 30, 'int');
		$timer   = Factory::getTimer();
		$result  = $this->doNothing($seconds);
		$timer->enforce_min_exec_time(false);

		return $result;
	}

	/**
	 * Save a specific maximum execution time preference to the database
	 *
	 * @return  bool
	 * @throws  Exception
	 *
	 * @noinspection PhpUnusedPrivateMethodInspection
	 */
	private function applymaxexec(): bool
	{
		// Get the user parameters
		$maxexec = JoomlaFactory::getApplication()->input
			->get('seconds', 2, 'int');

		// Save the settings
		$timer      = Factory::getTimer();
		$profile_id = Platform::getInstance()->get_active_profile();
		$config     = Factory::getConfiguration();
		$config->set('akeeba.tuning.max_exec_time', $maxexec);
		$config->set('akeeba.tuning.run_time_bias', '75');
		$config->set('akeeba.advanced.scan_engine', 'smart');
		$config->set('akeeba.advanced.archiver_engine', 'jpa');
		Platform::getInstance()->save_configuration($profile_id);

		// Enforce the min exec time
		$timer->enforce_min_exec_time(false);

		// Done!
		return true;
	}
}