<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\log;

use Yii;
use yii\base\InvalidConfigException;
use yii\helpers\FileHelper;

/**
 * FileTarget records log messages in a file.
 *
 * The log file is specified via [[logFile]]. If the size of the log file exceeds
 * [[maxFileSize]] (in kilo-bytes), a rotation will be performed, which renames
 * the current log file by suffixing the file name with '.1'. All existing log
 * files are moved backwards by one place, i.e., '.2' to '.3', '.1' to '.2', and so on.
 * The property [[maxLogFiles]] specifies how many files to keep.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class FileTarget extends Target
{
    /**
     * @var string log file path or path alias. If not set, it will use the "@runtime/logs/app.log" file.
     * The directory containing the log files will be automatically created if not existing.
     */
    public $logFile;
    /**
     * @var integer maximum log file size, in kilo-bytes. Defaults to 10240, meaning 10MB.
     */
    public $maxFileSize = 10240; // in KB
    /**
     * @var integer number of log files used for rotation. Defaults to 5.
     */
    public $maxLogFiles = 5;
    /**
     * @var integer the permission to be set for newly created log files.
     * This value will be used by PHP chmod() function. No umask will be applied.
     * If not set, the permission will be determined by the current environment.
     */
    public $fileMode;
    /**
     * @var integer the permission to be set for newly created directories.
     * This value will be used by PHP chmod() function. No umask will be applied.
     * Defaults to 0775, meaning the directory is read-writable by owner and group,
     * but read-only for other users.
     */
    public $dirMode = 0775;

    /**
     * Initializes the route.
     * This method is invoked after the route is created by the route manager.
     */
    public function init()
    {
        parent::init();
        if ($this->logFile === null) {
            $this->logFile = Yii::$app->getRuntimePath() . '/logs/app.log';
        } else {
            $this->logFile = Yii::getAlias($this->logFile);
        }
        $logPath = dirname($this->logFile);
        if (!is_dir($logPath)) {
            FileHelper::createDirectory($logPath, $this->dirMode, true);
        }
        if ($this->maxLogFiles < 1) {
            $this->maxLogFiles = 1;
        }
        if ($this->maxFileSize < 1) {
            $this->maxFileSize = 1;
        }
    }

    /**
     * Writes log messages to a file.
     * @throws InvalidConfigException if unable to open the log file for writing
     */
    public function export()
    {
        $text = implode("\n", array_map([$this, 'formatMessage'], $this->messages)) . "\n";
        if (($fp = @fopen($this->logFile, 'a')) === false) {
            throw new InvalidConfigException("Unable to append to log file: {$this->logFile}");
        }
        @flock($fp, LOCK_EX);
        if (@filesize($this->logFile) > $this->maxFileSize * 1024) {
            $this->rotateFiles();
            @flock($fp, LOCK_UN);
            @fclose($fp);
            @file_put_contents($this->logFile, $text, FILE_APPEND | LOCK_EX);
        } else {
            @fwrite($fp, $text);
            @flock($fp, LOCK_UN);
            @fclose($fp);
        }
        if ($this->fileMode !== null) {
            @chmod($this->logFile, $this->fileMode);
        }
    }

    /**
     * Rotates log files.
     */
    protected function rotateFiles()
    {
        $file = $this->logFile;
        for ($i = $this->maxLogFiles; $i > 0; --$i) {
            $rotateFile = $file . '.' . $i;
            if (is_file($rotateFile)) {
                // suppress errors because it's possible multiple processes enter into this section
                if ($i === $this->maxLogFiles) {
                    @unlink($rotateFile);
                } else {
                    @rename($rotateFile, $file . '.' . ($i + 1));
                }
            }
        }
        if (is_file($file)) {
            @rename($file, $file . '.1'); // suppress errors because it's possible multiple processes enter into this section
        }
    }
}
