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package io.muserver;

import io.netty.handler.codec.CorruptedFrameException;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.TimeoutException;

/**
 * A base class for server-side web sockets, that takes care of capturing the web socket session, responding
 * to pings, and closure events.
 * This is an alternative to implementing the {@link MuWebSocket} interface and is recommended so that any
 * additions to the interface are non-breaking to implementors.
 */
@SuppressWarnings("RedundantThrows") // because implementing classes might throw exceptions
public abstract class BaseWebSocket implements MuWebSocket {
    private MuWebSocketSession session;

    /**
     * @return The state of the current session
     */
    protected WebsocketSessionState state() {
        MuWebSocketSession session = this.session;
        return session == null ? WebsocketSessionState.NOT_STARTED : session.state();
    }

    @Override
    public void onConnect(MuWebSocketSession session) throws Exception {
        this.session = session;
    }

    @Override
    public void onText(String message, boolean isLast, DoneCallback onComplete) throws Exception {
        onComplete.onComplete(null);
    }

    @Override
    public void onBinary(ByteBuffer buffer, boolean isLast, DoneCallback onComplete) throws Exception {
        onComplete.onComplete(null);
    }

    @Override
    public void onClientClosed(int statusCode, String reason) throws Exception {
        try {
            session.close(statusCode, reason);
        } catch (IOException ignored) {
        }
    }

    @Override
    public void onPing(ByteBuffer payload, DoneCallback onComplete) throws Exception {
        session().sendPong(payload, onComplete);
    }

    @Override
    public void onPong(ByteBuffer payload, DoneCallback onComplete) throws Exception {
        onComplete.onComplete(null);
    }

    @Override
    public void onError(Throwable cause) throws Exception {
        if (!state().endState()) {
            if (cause instanceof TimeoutException) {
                session().close(1001, WebsocketSessionState.TIMED_OUT.name());
            } else if (cause instanceof CorruptedFrameException) {
                session().close(1008, WebsocketSessionState.ERRORED.name());
            } else if (session != null) {
                session().close(1011, WebsocketSessionState.ERRORED.name());
            }
        }
    }

    /**
     * Gets the websocket session
     *
     * @return A session that can be used to send message and events to the client.
     * @throws IllegalStateException Thrown if the socket has not been connected yet.
     */
    protected MuWebSocketSession session() {
        if (session == null) {
            throw new IllegalStateException("The websocket has not been connected yet");
        }
        return session;
    }

}