<?php

/*
 * This file is part of the Monolog package.
 *
 * (c) Jordi Boggiano <j.boggiano@seld.be>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Monolog;

use Monolog\Handler\HandlerInterface;
use Monolog\Handler\StreamHandler;
use Psr\Log\LoggerInterface;
use Psr\Log\InvalidArgumentException;

/**
 * Monolog log channel
 *
 * It contains a stack of Handlers and a stack of Processors,
 * and uses them to store records that are added to it.
 *
 * @author Jordi Boggiano <j.boggiano@seld.be>
 */
class Logger implements LoggerInterface
{
    /**
     * Detailed debug information
     */
    const DEBUG = 100;

    /**
     * Interesting events
     *
     * Examples: User logs in, SQL logs.
     */
    const INFO = 200;

    /**
     * Uncommon events
     */
    const NOTICE = 250;

    /**
     * Exceptional occurrences that are not errors
     *
     * Examples: Use of deprecated APIs, poor use of an API,
     * undesirable things that are not necessarily wrong.
     */
    const WARNING = 300;

    /**
     * Runtime errors
     */
    const ERROR = 400;

    /**
     * Critical conditions
     *
     * Example: Application component unavailable, unexpected exception.
     */
    const CRITICAL = 500;

    /**
     * Action must be taken immediately
     *
     * Example: Entire website down, database unavailable, etc.
     * This should trigger the SMS alerts and wake you up.
     */
    const ALERT = 550;

    /**
     * Urgent alert.
     */
    const EMERGENCY = 600;

    protected static $levels = array(
        100 => 'DEBUG',
        200 => 'INFO',
        250 => 'NOTICE',
        300 => 'WARNING',
        400 => 'ERROR',
        500 => 'CRITICAL',
        550 => 'ALERT',
        600 => 'EMERGENCY',
    );

    /**
     * @var DateTimeZone
     */
    protected static $timezone;

    protected $name;

    /**
     * The handler stack
     *
     * @var array of Monolog\Handler\HandlerInterface
     */
    protected $handlers;

    /**
     * Processors that will process all log records
     *
     * To process records of a single handler instead, add the processor on that specific handler
     *
     * @var array of callables
     */
    protected $processors;

    /**
     * @param string $name       The logging channel
     * @param array  $handlers   Optional stack of handlers, the first one in the array is called first, etc.
     * @param array  $processors Optional array of processors
     */
    public function __construct($name, array $handlers = array(), array $processors = array())
    {
        $this->name = $name;
        $this->handlers = $handlers;
        $this->processors = $processors;
    }

    /**
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Pushes a handler on to the stack.
     *
     * @param HandlerInterface $handler
     */
    public function pushHandler(HandlerInterface $handler)
    {
        array_unshift($this->handlers, $handler);
    }

    /**
     * Pops a handler from the stack
     *
     * @return HandlerInterface
     */
    public function popHandler()
    {
        if (!$this->handlers) {
            throw new \LogicException('You tried to pop from an empty handler stack.');
        }

        return array_shift($this->handlers);
    }

    /**
     * Adds a processor on to the stack.
     *
     * @param callable $callback
     */
    public function pushProcessor($callback)
    {
        if (!is_callable($callback)) {
            throw new \InvalidArgumentException('Processors must be valid callables (callback or object with an __invoke method), '.var_export($callback, true).' given');
        }
        array_unshift($this->processors, $callback);
    }

    /**
     * Removes the processor on top of the stack and returns it.
     *
     * @return callable
     */
    public function popProcessor()
    {
        if (!$this->processors) {
            throw new \LogicException('You tried to pop from an empty processor stack.');
        }

        return array_shift($this->processors);
    }

    /**
     * Adds a log record.
     *
     * @param  integer $level   The logging level
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addRecord($level, $message, array $context = array())
    {
        if (!$this->handlers) {
            $this->pushHandler(new StreamHandler('php://stderr', static::DEBUG));
        }

        if (!static::$timezone) {
            static::$timezone = new \DateTimeZone(date_default_timezone_get() ?: 'UTC');
        }

        $record = array(
            'message' => (string) $message,
            'context' => $context,
            'level' => $level,
            'level_name' => static::getLevelName($level),
            'channel' => $this->name,
            'datetime' => \DateTime::createFromFormat('U.u', sprintf('%.6F', microtime(true)), static::$timezone)->setTimezone(static::$timezone),
            'extra' => array(),
        );
        // check if any handler will handle this message
        $handlerKey = null;
        foreach ($this->handlers as $key => $handler) {
            if ($handler->isHandling($record)) {
                $handlerKey = $key;
                break;
            }
        }
        // none found
        if (null === $handlerKey) {
            return false;
        }

        // found at least one, process message and dispatch it
        foreach ($this->processors as $processor) {
            $record = call_user_func($processor, $record);
        }
        while (isset($this->handlers[$handlerKey]) &&
            false === $this->handlers[$handlerKey]->handle($record)) {
            $handlerKey++;
        }

        return true;
    }

    /**
     * Adds a log record at the DEBUG level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addDebug($message, array $context = array())
    {
        return $this->addRecord(static::DEBUG, $message, $context);
    }

    /**
     * Adds a log record at the INFO level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addInfo($message, array $context = array())
    {
        return $this->addRecord(static::INFO, $message, $context);
    }

    /**
     * Adds a log record at the NOTICE level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addNotice($message, array $context = array())
    {
        return $this->addRecord(static::NOTICE, $message, $context);
    }

    /**
     * Adds a log record at the WARNING level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addWarning($message, array $context = array())
    {
        return $this->addRecord(static::WARNING, $message, $context);
    }

    /**
     * Adds a log record at the ERROR level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addError($message, array $context = array())
    {
        return $this->addRecord(static::ERROR, $message, $context);
    }

    /**
     * Adds a log record at the CRITICAL level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addCritical($message, array $context = array())
    {
        return $this->addRecord(static::CRITICAL, $message, $context);
    }

    /**
     * Adds a log record at the ALERT level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addAlert($message, array $context = array())
    {
        return $this->addRecord(static::ALERT, $message, $context);
    }

    /**
     * Adds a log record at the EMERGENCY level.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function addEmergency($message, array $context = array())
    {
      return $this->addRecord(static::EMERGENCY, $message, $context);
    }

    /**
     * Gets all supported logging levels.
     * 
     * @return array Assoc array with human-readable level names => level codes.
     */
    public static function getLevels()
    {
        return array_flip(static::$levels);
    }

    /**
     * Gets the name of the logging level.
     *
     * @param  integer $level
     * @return string
     */
    public static function getLevelName($level)
    {
        if (!isset(static::$levels[$level])) {
            throw new InvalidArgumentException('Level "'.$level.'" is not defined, use one of: '.implode(', ', array_keys(static::$levels)));
        }

        return static::$levels[$level];
    }

    /**
     * Checks whether the Logger has a handler that listens on the given level
     *
     * @param  integer $level
     * @return Boolean
     */
    public function isHandling($level)
    {
        $record = array(
            'level' => $level,
        );

        foreach ($this->handlers as $handler) {
            if ($handler->isHandling($record)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Adds a log record at an arbitrary level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  mixed   $level   The log level
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function log($level, $message, array $context = array())
    {
        if (is_string($level) && defined(__CLASS__.'::'.strtoupper($level))) {
            $level = constant(__CLASS__.'::'.strtoupper($level));
        }

        return $this->addRecord($level, $message, $context);
    }

    /**
     * Adds a log record at the DEBUG level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function debug($message, array $context = array())
    {
        return $this->addRecord(static::DEBUG, $message, $context);
    }

    /**
     * Adds a log record at the INFO level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function info($message, array $context = array())
    {
        return $this->addRecord(static::INFO, $message, $context);
    }

    /**
     * Adds a log record at the INFO level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function notice($message, array $context = array())
    {
        return $this->addRecord(static::NOTICE, $message, $context);
    }

    /**
     * Adds a log record at the WARNING level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function warn($message, array $context = array())
    {
        return $this->addRecord(static::WARNING, $message, $context);
    }

    /**
     * Adds a log record at the WARNING level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function warning($message, array $context = array())
    {
        return $this->addRecord(static::WARNING, $message, $context);
    }

    /**
     * Adds a log record at the ERROR level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function err($message, array $context = array())
    {
        return $this->addRecord(static::ERROR, $message, $context);
    }

    /**
     * Adds a log record at the ERROR level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function error($message, array $context = array())
    {
        return $this->addRecord(static::ERROR, $message, $context);
    }

    /**
     * Adds a log record at the CRITICAL level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function crit($message, array $context = array())
    {
        return $this->addRecord(static::CRITICAL, $message, $context);
    }

    /**
     * Adds a log record at the CRITICAL level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function critical($message, array $context = array())
    {
        return $this->addRecord(static::CRITICAL, $message, $context);
    }

    /**
     * Adds a log record at the ALERT level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function alert($message, array $context = array())
    {
        return $this->addRecord(static::ALERT, $message, $context);
    }

    /**
     * Adds a log record at the EMERGENCY level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function emerg($message, array $context = array())
    {
        return $this->addRecord(static::EMERGENCY, $message, $context);
    }

    /**
     * Adds a log record at the EMERGENCY level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string  $message The log message
     * @param  array   $context The log context
     * @return Boolean Whether the record has been processed
     */
    public function emergency($message, array $context = array())
    {
        return $this->addRecord(static::EMERGENCY, $message, $context);
    }
}
