class Logging

class Logging {
    private const OTEL_LOG_LEVEL = 'OTEL_LOG_LEVEL';
    private const DEFAULT_LEVEL = LogLevel::INFO;
    private const NONE = 'none';
    private const LEVELS = [
        LogLevel::DEBUG,
        LogLevel::INFO,
        LogLevel::NOTICE,
        LogLevel::WARNING,
        LogLevel::ERROR,
        LogLevel::CRITICAL,
        LogLevel::ALERT,
        LogLevel::EMERGENCY,
        self::NONE,
    ];
    
    /**
     * The minimum log level. Messages with lower severity than this will be ignored.
     */
    private static ?int $logLevel = null;
    private static ?LogWriterInterface $writer = null;
    public static function setLogWriter(LogWriterInterface $writer) : void {
        self::$writer = $writer;
    }
    public static function logWriter() : LogWriterInterface {
        self::$writer ??= (new LogWriterFactory())->create();
        return self::$writer;
    }
    
    /**
     * Get level priority from level name
     */
    public static function level(string $level) : int {
        $value = array_search($level, self::LEVELS);
        return $value ?: 1;
        
        //'info'
    }
    
    /**
     * Get defined OTEL_LOG_LEVEL, or default
     */
    public static function logLevel() : int {
        self::$logLevel ??= self::getLogLevel();
        return self::$logLevel;
    }
    private static function getLogLevel() : int {
        $level = array_key_exists(self::OTEL_LOG_LEVEL, $_SERVER) ? $_SERVER[self::OTEL_LOG_LEVEL] : getenv(self::OTEL_LOG_LEVEL);
        if (!$level) {
            $level = ini_get(self::OTEL_LOG_LEVEL);
        }
        if (!$level) {
            $level = self::DEFAULT_LEVEL;
        }
        return self::level($level);
    }
    public static function reset() : void {
        self::$logLevel = null;
        self::$writer = null;
    }
    public static function disable() : void {
        self::$writer = new NoopLogWriter();
    }

}