<?php
/**
 * TLogger class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link https://github.com/pradosoft/prado
 * @license https://github.com/pradosoft/prado/blob/master/LICENSE
 */

namespace Prado\Util;

use Prado\Web\UI\TControl;

/**
 * TLogger class.
 *
 * TLogger records log messages in memory and implements the methods to
 * retrieve the messages with filter conditions, including log levels,
 * log categories, and by control.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 3.0
 */
class TLogger extends \Prado\TComponent
{
	/**
	 * Log levels.
	 */
	public const DEBUG = 0x01;
	public const INFO = 0x02;
	public const NOTICE = 0x04;
	public const WARNING = 0x08;
	public const ERROR = 0x10;
	public const ALERT = 0x20;
	public const FATAL = 0x40;
	/**
	 * @var array log messages
	 */
	private $_logs = [];
	/**
	 * @var int log levels (bits) to be filtered
	 */
	private $_levels;
	/**
	 * @var array list of categories to be filtered
	 */
	private $_categories;
	/**
	 * @var array list of control client ids to be filtered
	 */
	private $_controls;
	/**
	 * @var float timestamp used to filter
	 */
	private $_timestamp;

	/**
	 * Logs a message.
	 * Messages logged by this method may be retrieved via {@link getLogs}.
	 * @param string $message message to be logged
	 * @param int $level level of the message. Valid values include
	 * TLogger::DEBUG, TLogger::INFO, TLogger::NOTICE, TLogger::WARNING,
	 * TLogger::ERROR, TLogger::ALERT, TLogger::FATAL.
	 * @param string $category category of the message
	 * @param null|string|TControl $ctl control of the message
	 */
	public function log($message, $level, $category = 'Uncategorized', $ctl = null)
	{
		if ($ctl) {
			if ($ctl instanceof TControl) {
				$ctl = $ctl->getClientID();
			} elseif (!is_string($ctl)) {
				$ctl = null;
			}
		} else {
			$ctl = null;
		}
		$this->_logs[] = [$message, $level, $category, microtime(true), memory_get_usage(), $ctl];
	}

	/**
	 * Retrieves log messages.
	 * Messages may be filtered by log levels and/or categories and/or control client ids and/or timestamp.
	 * A level filter is specified by an integer, whose bits indicate the levels interested.
	 * For example, (TLogger::INFO | TLogger::WARNING) specifies INFO and WARNING levels.
	 * A category filter is specified by an array of categories to filter.
	 * A message whose category name starts with any filtering category
	 * will be returned. For example, a category filter array('Prado\Web','Prado\IO')
	 * will return messages under categories such as 'Prado\Web', 'Prado\IO',
	 * 'Prado\Web\UI', 'Prado\Web\UI\WebControls', etc.
	 * A control client id filter is specified by an array of control client id
	 * A message whose control client id starts with any filtering naming panels
	 * will be returned. For example, a category filter array('ctl0_body_header',
	 * 'ctl0_body_content_sidebar')
	 * will return messages under categories such as 'ctl0_body_header', 'ctl0_body_content_sidebar',
	 * 'ctl0_body_header_title', 'ctl0_body_content_sidebar_savebutton', etc.
	 * A timestamp filter is specified as an interger or float number.
	 * A message whose registered timestamp is less or equal the filter value will be returned.
	 * Level filter, category filter, control filter and timestamp filter are combinational, i.e., only messages
	 * satisfying all filter conditions will they be returned.
	 * @param null|int $levels level filter
	 * @param null|array $categories category filter
	 * @param null|array $controls control filter
	 * @param null|mixed $timestamp filter
	 * @return array list of messages. Each array elements represents one message
	 * with the following structure:
	 * array(
	 *   [0] => message
	 *   [1] => level
	 *   [2] => category
	 *   [3] => timestamp (by microtime(), float number));
	 *   [4] => memory in bytes
	 *   [5] => control client id
	 */
	public function getLogs($levels = null, $categories = null, $controls = null, $timestamp = null)
	{
		$this->_levels = $levels;
		$this->_categories = $categories;
		$this->_controls = $controls;
		$this->_timestamp = $timestamp;
		if (empty($levels) && empty($categories) && empty($controls) && null === $timestamp) {
			return $this->_logs;
		}
		$logs = $this->_logs;
		if (!empty($levels)) {
			$logs = array_values(array_filter(array_filter($logs, [$this, 'filterByLevels'])));
		}
		if (!empty($categories)) {
			$logs = array_values(array_filter(array_filter($logs, [$this, 'filterByCategories'])));
		}
		if (!empty($controls)) {
			$logs = array_values(array_filter(array_filter($logs, [$this, 'filterByControl'])));
		}
		if (null !== $timestamp) {
			$logs = array_values(array_filter(array_filter($logs, [$this, 'filterByTimeStamp'])));
		}
		return $logs;
	}

	/**
	 * Deletes log messages from the queue.
	 * Messages may be filtered by log levels and/or categories and/or control client ids and/or timestamp.
	 * A level filter is specified by an integer, whose bits indicate the levels interested.
	 * For example, (TLogger::INFO | TLogger::WARNING) specifies INFO and WARNING levels.
	 * A category filter is specified by an array of categories to filter.
	 * A message whose category name starts with any filtering category
	 * will be deleted. For example, a category filter array('Prado\Web','Prado\IO')
	 * will delete messages under categories such as 'Prado\Web', 'Prado\IO',
	 * 'Prado\Web\UI', 'Prado\Web\UI\WebControls', etc.
	 * A control client id filter is specified by an array of control client id
	 * A message whose control client id starts with any filtering naming panels
	 * will be deleted. For example, a category filter array('ctl0_body_header',
	 * 'ctl0_body_content_sidebar')
	 * will delete messages under categories such as 'ctl0_body_header', 'ctl0_body_content_sidebar',
	 * 'ctl0_body_header_title', 'ctl0_body_content_sidebar_savebutton', etc.
	 * A timestamp filter is specified as an interger or float number.
	 * A message whose registered timestamp is less or equal the filter value will be returned.
	 * Level filter, category filter, control filter and timestamp filter are combinational, i.e., only messages
	 * satisfying all filter conditions will they be returned.
	 * @param null|int $levels level filter
	 * @param null|array $categories category filter
	 * @param null|array $controls control filter
	 * @param null|mixed $timestamp timestamp filter
	 */
	public function deleteLogs($levels = null, $categories = null, $controls = null, $timestamp = null)
	{
		$this->_levels = $levels;
		$this->_categories = $categories;
		$this->_controls = $controls;
		$this->_timestamp = $timestamp;
		if (empty($levels) && empty($categories) && empty($controls) && null === $timestamp) {
			$this->_logs = [];
			return;
		}
		$logs = $this->_logs;
		if (!empty($levels)) {
			$logs = array_filter(array_filter($logs, [$this, 'filterByLevels']));
		}
		if (!empty($categories)) {
			$logs = array_filter(array_filter($logs, [$this, 'filterByCategories']));
		}
		if (!empty($controls)) {
			$logs = array_filter(array_filter($logs, [$this, 'filterByControl']));
		}
		if (null !== $timestamp) {
			$logs = array_filter(array_filter($logs, [$this, 'filterByTimeStamp']));
		}
		$this->_logs = array_values(array_diff_key($this->_logs, $logs));
	}

	/**
	 * Filter function used by {@link getLogs}.
	 * @param array $value element to be filtered
	 */
	private function filterByCategories($value)
	{
		foreach ($this->_categories as $category) {
			// element 2 is the category
			if ($value[2] === $category || strpos($value[2], $category . '.') === 0) {
				return $value;
			}
		}
		return false;
	}

	/**
	 * Filter function used by {@link getLogs}
	 * @param array $value element to be filtered
	 */
	private function filterByLevels($value)
	{
		// element 1 are the levels
		if ($value[1] & $this->_levels) {
			return $value;
		} else {
			return false;
		}
	}

	/**
	 * Filter function used by {@link getLogs}
	 * @param array $value element to be filtered
	 */
	private function filterByControl($value)
	{
		// element 5 are the control client ids
		foreach ($this->_controls as $control) {
			if ($value[5] === $control || strpos($value[5], $control) === 0) {
				return $value;
			}
		}
		return false;
	}

	/**
	 * Filter function used by {@link getLogs}
	 * @param array $value element to be filtered
	 */
	private function filterByTimeStamp($value)
	{
		// element 3 is the timestamp
		if ($value[3] <= $this->_timestamp) {
			return $value;
		} else {
			return false;
		}
	}
}