package org.handwerkszeug.dns.record;

import java.util.List;

import org.handwerkszeug.dns.Name;
import org.handwerkszeug.dns.NameCompressor;
import org.handwerkszeug.dns.RRType;
import org.handwerkszeug.dns.ResourceRecord;
import org.handwerkszeug.util.CompareUtil;

import io.netty.buffer.ByteBuf;

/**
 * 3.3.9. MX RDATA format
 * <p>
 * <pre>
 *                                   1  1  1  1  1  1
 *     0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
 *    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *    |                  PREFERENCE                   |
 *    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *    /                   EXCHANGE                    /
 *    /                                               /
 *    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 * </pre>
 *
 * @author taichi
 */
public
class MXRecord extends AbstractRecord<MXRecord> {

    /**
     * A 16 bit integer which specifies the preference given to this RR among
     * others at the same owner. Lower values are preferred.
     */
    protected int preference;

    /**
     * RFC 974 the name of a host.
     */
    protected Name exchange;

    public
    MXRecord() {
        super(RRType.MX);
    }

    public
    MXRecord(MXRecord from) {
        super(from);
        this.preference = from.preference();
        this.exchange = from.exchange();
    }

    public
    int preference() {
        return this.preference;
    }

    public
    Name exchange() {
        return this.exchange;
    }

    @Override
    protected
    void parseRDATA(ByteBuf buffer) {
        this.preference = buffer.readUnsignedShort();
        this.exchange = new Name(buffer);

    }

    @Override
    protected
    void writeRDATA(ByteBuf buffer, NameCompressor compressor) {
        buffer.writeShort(this.preference);
        this.exchange.write(buffer, compressor);
    }

    @Override
    protected
    ResourceRecord newInstance() {
        return new MXRecord(this);
    }

    @Override
    public
    int compareTo(MXRecord o) {
        if (this == o) {
            return 0;
        }
        int result = super.compareTo(o);
        if (result == 0) {
            result = CompareUtil.compare(this.preference(), o.preference());
            if (result == 0) {
                result = this.exchange()
                             .compareTo(o.exchange());
            }
        }
        return result;
    }

    @Override
    public
    String toString() {
        StringBuilder stb = new StringBuilder();
        stb.append(super.toString());
        stb.append(' ');
        stb.append(this.preference());
        stb.append(' ');
        stb.append(this.exchange());
        return stb.toString();
    }

    @Override
    public
    void setRDATA(List<String> list) {
        if (2 == list.size()) {
            int pref = Integer.parseInt(list.get(0));
            if (-1 < pref && pref < 65536) {
                this.preference = pref;
            }
            else {
                // TODO error message.
                throw new IllegalArgumentException();
            }
            this.exchange = new Name(list.get(1));
        }
        else {
            // TODO error message
            throw new IllegalArgumentException();
        }
    }
}