package org.handwerkszeug.dns.record;

import java.net.InetAddress;
import java.util.Arrays;
import java.util.List;

import org.handwerkszeug.dns.NameCompressor;
import org.handwerkszeug.dns.RRType;
import org.handwerkszeug.dns.ResourceRecord;
import org.handwerkszeug.dns.client.WKPortNumbers;
import org.handwerkszeug.dns.client.WKProtocols;
import org.handwerkszeug.util.AddressUtil;
import org.handwerkszeug.util.CompareUtil;

import io.netty.buffer.ByteBuf;

/**
 * 3.4.2. WKS RDATA format
 * <p>
 * <pre>
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *     |                    ADDRESS                    |
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 *     |       PROTOCOL        |                       |
 *     +--+--+--+--+--+--+--+--+                       |
 *     |                                               |
 *     /                   <BIT MAP>                   /
 *     /                                               /
 *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 * </pre>
 * <p>
 * The WKS record is used to describe the well known services supported by a
 * particular protocol on a particular internet address. The PROTOCOL field
 * specifies an IP protocol number, and the bit map has one bit per port of the
 * specified protocol. The first bit corresponds to port 0, the second to port
 * 1, etc. If the bit map does not include a bit for a protocol of interest,
 * that bit is assumed zero. The appropriate values and mnemonics for ports and
 * protocols are specified in [RFC-1010].
 * </p>
 *
 * @author taichi
 */
public
class WKSRecord extends AbstractRecord<WKSRecord> {

    /**
     * An 32 bit Internet address
     */
    protected long address;

    /**
     * An 8 bit IP protocol number
     */
    protected short protocol;

    /**
     * A variable length bit map. The bit map must be a multiple of 8 bits long.
     */
    protected byte[] bitmap;

    public
    WKSRecord() {
        super(RRType.WKS);
    }

    public
    WKSRecord(WKSRecord from) {
        super(from);
        this.address = from.address;
        this.protocol = from.protocol();
        byte[] ary = from.bitmap();
        if (ary != null) {
            this.bitmap(Arrays.copyOf(ary, ary.length));
        }
    }

    public
    short protocol() {
        return this.protocol;
    }

    public
    byte[] bitmap() {
        return this.bitmap;
    }

    public
    void bitmap(byte[] bytes) {
        this.bitmap = bytes;
    }

    @Override
    protected
    void parseRDATA(ByteBuf buffer) {
        this.address = buffer.readUnsignedInt();
        this.protocol = buffer.readUnsignedByte();
        this.bitmap = new byte[rdlength() - 5];// (32bit + 8bit) / 8bit
        buffer.readBytes(this.bitmap);
    }

    @Override
    protected
    void writeRDATA(ByteBuf buffer, NameCompressor compressor) {
        buffer.writeInt((int) this.address);
        buffer.writeByte(this.protocol);
        buffer.writeBytes(this.bitmap);
    }

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

    @Override
    public
    int compareTo(WKSRecord o) {
        if (this == o) {
            return 0;
        }
        int result = super.compareTo(o);
        if (result != 0) {
            return result;
        }
        result = CompareUtil.compare(this.address, o.address);
        if (result != 0) {
            return result;
        }
        result = CompareUtil.compare(this.protocol(), o.protocol());
        if (result != 0) {
            return result;
        }
        return CompareUtil.compare(this.bitmap(), o.bitmap());
    }

    /**
     * @see WKProtocols
     * @see WKPortNumbers
     */
    @Override
    public
    String toString() {
        StringBuilder stb = new StringBuilder();
        stb.append(super.toString());
        stb.append(' ');
        stb.append(this.address()
                       .getHostAddress());
        stb.append(' ');
        stb.append(this.protocol());
        return stb.toString();
    }

    public
    InetAddress address() {
        return AddressUtil.getByAddress(this.address);
    }

    @Override
    public
    void setRDATA(List<String> list) {
        // TODO Auto-generated method stub

    }

    public
    void protocol(short no) {
        this.protocol = no;
    }
}