package jxm.JWS.FR;

import jxm.CHRF;
import jxm.JWS.EX.InvalidDataException;
import jxm.JWS.EX.InvalidFrameException;

import java.nio.ByteBuffer;


public class CloseFrameBuilder extends FramedataImpl1 implements CloseFrame {

    static final ByteBuffer emptybytebuffer = ByteBuffer.allocate(0);

    private int code;
    private String reason;

    public CloseFrameBuilder() {
        super(Opcode.CLOSING);
        setFin(true);
    }

    public CloseFrameBuilder(int code) throws InvalidDataException {
        super(Opcode.CLOSING);
        setFin(true);
        setCodeAndMessage(code, "");
    }

    public CloseFrameBuilder(int code, String m) throws InvalidDataException {
        super(Opcode.CLOSING);
        setFin(true);
        setCodeAndMessage(code, m);
    }

    private void setCodeAndMessage(int code, String m) throws InvalidDataException {
        if (m == null) {
            m = "";
        }
        // CloseFrame.TLS_ERROR is not allowed to be transfered over the wire
        if (code == TLS_ERROR) {
            code = NOCODE;
            m = "";
        }
        if (code == NOCODE) {
            if (0 < m.length()) {
                throw new InvalidDataException(PROTOCOL_ERROR, "A close frame must have a closecode if it has a reason");
            }
            return;// empty payload
        }

        byte[] by = CHRF.utf8Bytes(m);
        ByteBuffer buf = ByteBuffer.allocate(4);
        buf.putInt(code);
        buf.position(2);
        ByteBuffer pay = ByteBuffer.allocate(2 + by.length);
        pay.put(buf);
        pay.put(by);
        pay.rewind();
        setPayload(pay);
    }

    private void initCloseCode() throws InvalidFrameException {
        code = NOCODE;
        ByteBuffer payload = super.getPayloadData();
        payload.mark();
        if (payload.remaining() >= 2) {
            ByteBuffer bb = ByteBuffer.allocate(4);
            bb.position(2);
            bb.putShort(payload.getShort());
            bb.position(0);
            code = bb.getInt();

            if (code == ABNORMAL_CLOSE || code == TLS_ERROR || code == NOCODE || code > 4999 || code < 1000 || code == 1004) {
                throw new InvalidFrameException("closecode must not be sent over the wire: " + code);
            }
        }
        payload.reset();
    }

    @Override
    public int getCloseCode() {
        return code;
    }

    private void initMessage() throws InvalidDataException {
        if (code == NOCODE) {
            reason = CHRF.stringUtf8(super.getPayloadData());
        } else {
            ByteBuffer b = super.getPayloadData();
            int mark = b.position();// because stringUtf8 also creates a mark
            try {
                b.position(b.position() + 2);
                reason = CHRF.stringUtf8(b);
            } catch (IllegalArgumentException e) {
                throw new InvalidFrameException(e);
            } finally {
                b.position(mark);
            }
        }
    }

    @Override
    public String getMessage() {
        return reason;
    }

    @Override
    public String toString() {
        return super.toString() + "code: " + code;
    }

    @Override
    public void setPayload(ByteBuffer payload) throws InvalidDataException {
        super.setPayload(payload);
        initCloseCode();
        initMessage();
    }

    @Override
    public ByteBuffer getPayloadData() {
        if (code == NOCODE)
            return emptybytebuffer;
        return super.getPayloadData();
    }

}