package vs;

import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * RFC 5424 (https://datatracker.ietf.org/doc/html/rfc5424) compliant log
 * messages as immutable Java objects
 *
 * @author Sandro Leuchter
 *
 */
public class SyslogMessage implements Serializable {

    private static final long serialVersionUID = -5895573029109990861L;
    private final Facility fac;
    private final Severity sev;
    private final AsciiChars.L255 host;
    private final AsciiChars.L048 appName;
    private final AsciiChars.L128 procId;
    private final AsciiChars.L032 msgId;
    private final StructuredData data;
    private final Message message;

    public SyslogMessage(
        Facility fac,
        Severity sev,
        AsciiChars.L255 host,
        AsciiChars.L048 appName,
        AsciiChars.L128 procId,
        AsciiChars.L032 msgId,
        StructuredData data,
        Message message
    ) {
        this.fac = fac;
        this.sev = sev;
        this.host = host;
        this.appName = appName;
        this.procId = procId;
        this.msgId = msgId;
        this.data = data;
        this.message = message;
    }

    public Facility fac() {
        return this.fac;
    }

    public Severity sev() {
        return sev;
    }

    public AsciiChars.L255 host() {
        return host;
    }

    public AsciiChars.L048 appName() {
        return appName;
    }

    public AsciiChars.L128 procId() {
        return procId;
    }

    public AsciiChars.L032 msgId() {
        return msgId;
    }

    public StructuredData data() {
        return data;
    }

    public Message message() {
        return message;
    }

    public static int version() {
        return VERSION;
    }

    public static enum Facility {
        KERNEL,
        USER,
        MAIL_SYSTEM,
        SYS_DAEMON,
        SECURITY1,
        INTERNAL,
        PRINTER,
        NEWS,
        UUCP,
        CLOCK1,
        SECURITY2,
        FTP,
        NTP,
        AUDIT,
        ALERT,
        CLOCK2,
        LOCAL0,
        LOCAL1,
        LOCAL2,
        LOCAL3,
        LOCAL4,
        LOCAL5,
        LOCAL6,
        LOCAL7,
    }

    public static enum Severity {
        EMERGENCY,
        ALERT,
        CRITICAL,
        ERROR,
        WARNING,
        NOTICE,
        INFORMATIONAL,
        DEBUG,
    }

    public static interface Message {
        public Object message();

        public int length();
    }

    public static class BinaryMessage implements Message {

        private Byte[] message;

        public BinaryMessage(Byte[] message) {
            this.message = message;
        }

        @Override
        public String toString() {
            return message.toString();
        }

        @Override
        public Object message() {
            return this.message;
        }

        @Override
        public int length() {
            return this.message.length;
        }
    }

    public static class TextMessage implements Message {

        private String message; // UTF8

        public TextMessage(String message) {
            this.message = message;
        }

        @Override
        public String toString() {
            return "\u00EF\u00BB\u00BF" + message.toString();
        }

        @Override
        public Object message() {
            return this.message;
        }

        @Override
        public int length() {
            return this.message.length();
        }
    }

    static final int VERSION = 1; // RFC 5424, Mar 2009

    @Override
    public String toString() {
        var prival = String.valueOf(fac().ordinal() * 8 + sev().ordinal());
        var d = "";
        if (data() != null) {
            d = " " + data();
        }
        var m = "";
        if (
            message() != null &&
            message().message() != null &&
            message().length() > 0
        ) {
            m = " " + message();
        }
        var timestamp = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX").format(
            new Date()
        );
        return (
            "<" +
            prival +
            ">" +
            VERSION +
            " " +
            timestamp +
            " " +
            host().toString() +
            " " +
            appName().toString() +
            " " +
            procId().toString() +
            " " +
            msgId().toString() +
            d +
            m
        );
    }
}