<?php

/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2011 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\CMS\Log;

// phpcs:disable PSR1.Files.SideEffects
\defined('_JEXEC') or die;
// phpcs:enable PSR1.Files.SideEffects

/**
 * Joomla! Log Class
 *
 * This class hooks into the global log configuration settings to allow for user configured
 * logging events to be sent to where the user wishes them to be sent. On high load sites
 * Syslog is probably the best (pure PHP function), then the text file based loggers (CSV, W3c
 * or plain Formattedtext) and finally MySQL offers the most features (e.g. rapid searching)
 * but will incur a performance hit due to INSERT being issued.
 *
 * @since  1.7.0
 */
class Log
{
    /**
     * All log priorities.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const ALL = 30719;

    /**
     * The system is unusable.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const EMERGENCY = 1;

    /**
     * Action must be taken immediately.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const ALERT = 2;

    /**
     * Critical conditions.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const CRITICAL = 4;

    /**
     * Error conditions.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const ERROR = 8;

    /**
     * Warning conditions.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const WARNING = 16;

    /**
     * Normal, but significant condition.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const NOTICE = 32;

    /**
     * Informational message.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const INFO = 64;

    /**
     * Debugging message.
     *
     * @var    integer
     * @since  1.7.0
     */
    public const DEBUG = 128;

    /**
     * The global Log instance.
     *
     * @var    Log
     * @since  1.7.0
     */
    protected static $instance;

    /**
     * Container for Logger configurations.
     *
     * @var    array
     * @since  1.7.0
     */
    protected $configurations = [];

    /**
     * Container for Logger objects.
     *
     * @var    Logger[]
     * @since  1.7.0
     */
    protected $loggers = [];

    /**
     * Lookup array for loggers.
     *
     * @var    array
     * @since  1.7.0
     */
    protected $lookup = [];

    /**
     * The registry of available loggers
     *
     * @var    LoggerRegistry
     * @since  4.0.0
     */
    protected $loggerRegistry;

    /**
     * Constructor.
     *
     * @since   1.7.0
     */
    protected function __construct()
    {
        $this->loggerRegistry = new LoggerRegistry();
    }

    /**
     * Method to add an entry to the log.
     *
     * @param   mixed    $entry     The LogEntry object to add to the log or the message for a new LogEntry object.
     * @param   integer  $priority  Message priority.
     * @param   string   $category  Type of entry
     * @param   string   $date      Date of entry (defaults to now if not specified or blank)
     * @param   array    $context   An optional array with additional message context.
     *
     * @return  void
     *
     * @since   1.7.0
     */
    public static function add($entry, $priority = self::INFO, $category = '', $date = null, array $context = [])
    {
        // Automatically instantiate the singleton object if not already done.
        if (empty(static::$instance)) {
            static::setInstance(new static());
        }

        // If the entry object isn't a LogEntry object let's make one.
        if (!($entry instanceof LogEntry)) {
            $entry = new LogEntry((string) $entry, $priority, $category, $date, $context);
        }

        static::$instance->addLogEntry($entry);
    }

    /**
     * Add a logger to the Log instance.  Loggers route log entries to the correct files/systems to be logged.
     *
     * @param   array    $options     The object configuration array.
     * @param   integer  $priorities  Message priority
     * @param   array    $categories  Types of entry
     * @param   boolean  $exclude     If true, all categories will be logged except those in the $categories array
     *
     * @return  void
     *
     * @since   1.7.0
     */
    public static function addLogger(array $options, $priorities = self::ALL, $categories = [], $exclude = false)
    {
        // Automatically instantiate the singleton object if not already done.
        if (empty(static::$instance)) {
            static::setInstance(new static());
        }

        static::$instance->addLoggerInternal($options, $priorities, $categories, $exclude);
    }

    /**
     * Register a logger to the registry
     *
     * @param   string   $key      The service key to be registered
     * @param   string   $class    The class name of the logger
     * @param   boolean  $replace  Flag indicating the service key may replace an existing definition
     *
     * @return  void
     *
     * @since   4.0.0
     */
    public function registerLogger(string $key, string $class, bool $replace = false)
    {
        // Automatically instantiate the singleton object if not already done.
        if (empty(static::$instance)) {
            static::setInstance(new static());
        }

        static::$instance->loggerRegistry->register($key, $class, $replace);
    }

    /**
     * Add a logger to the Log instance.  Loggers route log entries to the correct files/systems to be logged.
     * This method allows you to extend Log completely.
     *
     * @param   array    $options     The object configuration array.
     * @param   integer  $priorities  Message priority
     * @param   array    $categories  Types of entry
     * @param   boolean  $exclude     If true, all categories will be logged except those in the $categories array
     *
     * @return  void
     *
     * @since   1.7.0
     */
    protected function addLoggerInternal(array $options, $priorities = self::ALL, $categories = [], $exclude = false)
    {
        // The default logger is the formatted text log file.
        if (empty($options['logger'])) {
            $options['logger'] = 'formattedtext';
        }

        $options['logger'] = strtolower($options['logger']);

        // Special case - if a Closure object is sent as the callback (in case of CallbackLogger)
        // Closure objects are not serializable so swap it out for a unique id first then back again later
        if (isset($options['callback'])) {
            if (is_a($options['callback'], 'closure')) {
                $callback            = $options['callback'];
                $options['callback'] = spl_object_hash($options['callback']);
            } elseif (\is_array($options['callback']) && \count($options['callback']) == 2 && \is_object($options['callback'][0])) {
                $callback            = $options['callback'];
                $options['callback'] = spl_object_hash($options['callback'][0]) . '::' . $options['callback'][1];
            }
        }

        // Generate a unique signature for the Log instance based on its options.
        $signature = md5(serialize($options));

        // Now that the options array has been serialized, swap the callback back in
        if (isset($callback)) {
            $options['callback'] = $callback;
        }

        // Register the configuration if it doesn't exist.
        if (empty($this->configurations[$signature])) {
            $this->configurations[$signature] = $options;
        }

        $this->lookup[$signature] = (object) [
            'priorities' => $priorities,
            'categories' => array_map('strtolower', (array) $categories),
            'exclude'    => (bool) $exclude,
        ];
    }

    /**
     * Creates a delegated PSR-3 compatible logger from the current singleton instance. This method always returns a new delegated logger.
     *
     * @return  DelegatingPsrLogger
     *
     * @since   3.8.0
     */
    public static function createDelegatedLogger()
    {
        // Ensure a singleton instance has been created first
        if (empty(static::$instance)) {
            static::setInstance(new static());
        }

        return new DelegatingPsrLogger(static::$instance);
    }

    /**
     * Returns a reference to the a Log object, only creating it if it doesn't already exist.
     * Note: This is principally made available for testing and internal purposes.
     *
     * @param   Log  $instance  The logging object instance to be used by the static methods.
     *
     * @return  void
     *
     * @since   1.7.0
     */
    public static function setInstance($instance)
    {
        if (($instance instanceof Log) || $instance === null) {
            static::$instance = & $instance;
        }
    }

    /**
     * Method to add an entry to the appropriate loggers.
     *
     * @param   LogEntry  $entry  The LogEntry object to send to the loggers.
     *
     * @return  void
     *
     * @since   1.7.0
     * @throws  \RuntimeException
     */
    protected function addLogEntry(LogEntry $entry)
    {
        // Find all the appropriate loggers based on priority and category for the entry.
        $loggers = $this->findLoggers($entry->priority, $entry->category);

        foreach ((array) $loggers as $signature) {
            // Attempt to instantiate the logger object if it doesn't already exist.
            if (empty($this->loggers[$signature])) {
                if ($this->loggerRegistry->hasLogger($this->configurations[$signature]['logger'])) {
                    $class = $this->loggerRegistry->getLoggerClass($this->configurations[$signature]['logger']);
                } else {
                    @trigger_error(
                        \sprintf(
                            'Attempting to automatically resolve loggers to the %s namespace is deprecated as of 4.0 and will be removed in 7.0.'
                            . ' Use the logger registry instead.',
                            __NAMESPACE__
                        ),
                        E_USER_DEPRECATED
                    );

                    $class = __NAMESPACE__ . '\\Logger\\' . ucfirst($this->configurations[$signature]['logger']) . 'Logger';

                    if (!class_exists($class)) {
                        throw new \RuntimeException('Unable to create a Logger instance: ' . $class);
                    }
                }

                $this->loggers[$signature] = new $class($this->configurations[$signature]);
            }

            // Add the entry to the logger.
            $this->loggers[$signature]->addEntry(clone $entry);
        }
    }

    /**
     * Method to find the loggers to use based on priority and category values.
     *
     * @param   integer  $priority  Message priority.
     * @param   string   $category  Type of entry
     *
     * @return  array  The array of loggers to use for the given priority and category values.
     *
     * @since   1.7.0
     */
    protected function findLoggers($priority, $category)
    {
        $loggers = [];

        // Sanitize inputs.
        $priority = (int) $priority;
        $category = strtolower((string) $category);

        // Let's go iterate over the loggers and get all the ones we need.
        foreach ((array) $this->lookup as $signature => $rules) {
            // Check to make sure the priority matches the logger.
            if ($priority & $rules->priorities) {
                if ($rules->exclude) {
                    // If either there are no set categories or the category (including the empty case) is not in the list of excluded categories, add this logger.
                    if (empty($rules->categories) || !\in_array($category, $rules->categories)) {
                        $loggers[] = $signature;
                    }
                } else {
                    // If either there are no set categories (meaning all) or the specific category is set, add this logger.
                    if (empty($rules->categories) || \in_array($category, $rules->categories)) {
                        $loggers[] = $signature;
                    }
                }
            }
        }

        return $loggers;
    }
}
