<?php

namespace BSR\Lib;

class Logger {
    const QUIET = 0;
    const NORMAL = 1;
    const VERBOSE = 2;

    private static $start;
    private static $data = array();
    private static $log = '';

    private static function ip() {
        if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            return array_shift(
                array_map('trim', explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']))
            );
        } else if (isset($_SERVER['REMOTE_ADDR'])) {
            return $_SERVER['REMOTE_ADDR'];
        }

        return '(n-a)';
    }

    public static function start($data = array()) {
        self::$start = microtime(true);

        self::$data = $data + array(
            'ip' => self::ip(),
            'date' => date('d.m.Y H:i:s'),
            'func' => '(none)',
            'version' => '(none)',
            'error' => ''
        );
    }

    public static function info($info, $key = null) {
        if(is_null($key)) {
            self::$data = array_merge(self::$data, $info);
        } else {
            self::$data[$key] = $info;
        }
    }

    /**
     * Log a message that will be displayed in the logs if the configuration
     * says so.
     *
     * @param string $message
     * @param int $verbosity
     */
    public static function log($message, $verbosity = Logger::VERBOSE) {
        if(Configuration::get('log.verbosity') < $verbosity) {
            return;
        }

        self::$log .= $message."\n";
    }

    public static function stop($data = null) {
        if(! is_null($data)) {
            self::info($data);
        }

        $time = (microtime(true) - self::$start) * 1000;
        self::$data['time'] = round($time, 2).'ms';

        if(Configuration::get('log.verbosity') > Logger::QUIET) {
            $format = Configuration::get('log.format');

            $patterns = array_map(function($p) { return "%$p%"; }, array_keys(self::$data));
            $msg = str_replace($patterns, array_values(self::$data), $format)."\n";

            if(strlen(self::$log) > 0) {
                $msg .= self::$log;
            }

            $file = Configuration::get('log.file');
            if(! file_exists($file)) {
                mkdir(dirname($file), 0777, true);
                touch($file);
            } else {
                $mtime = filemtime($file);
                // start of the current day
                $start = strtotime("midnight");

                // log rotate if the last entry in the log is from yesterday
                if($mtime < $start) {
                    $files = glob($file.'.?');
                    natsort($files);
                    $files = array_reverse($files);
                    $files[] = $file;

                    // we count before adding the next file
                    $len = count($files);

                    $next = intval(substr($files[0], -1)) + 1;
                    $next = $next == 1 ? "$file.1" : substr($files[0], 0, -1).$next;

                    array_unshift($files, $next);
                    for($i = 0; $i < $len; ++$i) {
                        // move all the log files to the next name
                        rename($files[$i + 1], $files[$i]);
                    }

                    // delete all files with a number bigger than 9
                    $files = glob($file.'.??');
                    array_map('unlink', $files);

                    // recreate the new log file
                    touch($file);
                }
            }
            file_put_contents($file, $msg, FILE_APPEND | LOCK_EX);
        }
    }

    public static function data() {
        return self::$data;
    }

    public static function getLastLogs($offset = null) {
        $file = Configuration::get('log.file');
        if(! file_exists($file)) {
            return 'No log yet !';
        }

        $f = fopen($file, 'r');

        $len = 8192;

        fseek($f, 0, SEEK_END);
        $size = ftell($f);
        if(is_null($offset) || $offset > $size) {
            $offset = $size - $len;
        }
        $offset = max(0, $offset);

        fseek($f, $offset);

        // remove the first line that may be incomplete
        $buffer = fread($f, $len);
        $buffer = explode("\n", $buffer);
        array_shift($buffer);
        $buffer = implode("\n", $buffer);
        // continue reading until the end of the file
        while(! feof($f)) {
            $buffer .= fread($f, $len);
        }

        fclose($f);

        return $buffer;
    }
}