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*/package com.lutao.cloud.iot.mqtt.core.server.http.core;


import com.lutao.cloud.iot.mqtt.core.server.MqttConst;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.tio.core.ChannelContext;
import org.tio.core.Tio;
import org.tio.core.TioConfig;
import org.tio.core.exception.TioDecodeException;
import org.tio.core.intf.Packet;
import org.tio.http.common.*;
import org.tio.http.common.handler.HttpRequestHandler;
import org.tio.server.intf.ServerAioHandler;
import org.tio.utils.hutool.StrUtil;
import org.tio.websocket.common.*;
import org.tio.websocket.common.util.BASE64Util;
import org.tio.websocket.common.util.SHA1Util;
import org.tio.websocket.server.WsServerAioHandler;
import org.tio.websocket.server.handler.IWsMsgHandler;

import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.util.*;

/**
 * websocket 和 http 共存
 *
 * @author tanyaowu

 */
public class MqttWebServerAioHandler implements ServerAioHandler {
	private static Logger log = LoggerFactory.getLogger(WsServerAioHandler.class);
	/**
	 * value: List<WsRequest>
	 */
	private static final String NOT_FINAL_WEBSOCKET_PACKET_PARTS = "TIO_N_F_W_P_P";
	/**
	 * SEC_WEBSOCKET_KEY 后缀
	 */
	private static final String SEC_WEBSOCKET_KEY_SUFFIX = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
	private static final byte[] SEC_WEBSOCKET_KEY_SUFFIX_BYTES = SEC_WEBSOCKET_KEY_SUFFIX.getBytes();
	/**
	 * websocket子协议
	 */
	private static final String SEC_WEBSOCKET_PROTOCOL = "sec-websocket-protocol";
	private static final HeaderName HEADER_NAME_SEC_WEBSOCKET_PROTOCOL = HeaderName.from(SEC_WEBSOCKET_PROTOCOL);
	private final HttpConfig httpConfig;
	private final HttpRequestHandler requestHandler;
	private final IWsMsgHandler wsMsgHandler;

	public MqttWebServerAioHandler(HttpConfig httpConfig,
								   HttpRequestHandler requestHandler,
								   IWsMsgHandler wsMsgHandler) {
		this.httpConfig = httpConfig;
		this.requestHandler = requestHandler;
		this.wsMsgHandler = wsMsgHandler;
	}

	@SuppressWarnings("unchecked")
	@Override
	public Packet decode(ByteBuffer buffer, int limit, int position, int readableLength, ChannelContext context) throws TioDecodeException {
		WsSessionContext wsSessionContext = (WsSessionContext) context.get();
		// 尚未握手
		if (wsSessionContext == null) {
			HttpRequest request = HttpRequestDecoder.decode(buffer, limit, position, readableLength, context, httpConfig);
			if (request == null) {
				return null;
			}
			HttpResponse httpResponse = updateWebSocketProtocol(request);
			// 普通 http 非 websocket
			if (httpResponse == null) {
				context.set(MqttConst.IS_HTTP, (byte) 1);
				return request;
			}
			wsSessionContext = new WsSessionContext();
			context.set(wsSessionContext);
			wsSessionContext.setHandshakeRequest(request);
			wsSessionContext.setHandshakeResponse(httpResponse);
			WsRequest wsRequestPacket = new WsRequest();
			wsRequestPacket.setHandShake(true);
			return wsRequestPacket;
		}
		WsRequest websocketPacket = WsServerDecoder.decode(buffer, context);
		if (websocketPacket != null) {
			// 数据包尚未完成
			if (!websocketPacket.isWsEof()) {
				List<WsRequest> parts = (List<WsRequest>) context.get(NOT_FINAL_WEBSOCKET_PACKET_PARTS);
				if (parts == null) {
					parts = new ArrayList<>();
					context.set(NOT_FINAL_WEBSOCKET_PACKET_PARTS, parts);
				}
				parts.add(websocketPacket);
			} else {
				List<WsRequest> parts = (List<WsRequest>) context.get(NOT_FINAL_WEBSOCKET_PACKET_PARTS);
				if (parts != null) {
					context.set(NOT_FINAL_WEBSOCKET_PACKET_PARTS, null);

					parts.add(websocketPacket);
					WsRequest first = parts.get(0);
					websocketPacket.setWsOpcode(first.getWsOpcode());

					int allBodyLength = 0;
					for (WsRequest wsRequest : parts) {
						allBodyLength += wsRequest.getBody().length;
					}

					byte[] allBody = new byte[allBodyLength];
					int index = 0;
					for (WsRequest wsRequest : parts) {
						System.arraycopy(wsRequest.getBody(), 0, allBody, index, wsRequest.getBody().length);
						index += wsRequest.getBody().length;
					}
					websocketPacket.setBody(allBody);
				}
				HttpRequest handshakeRequest = wsSessionContext.getHandshakeRequest();
				if (websocketPacket.getWsOpcode() != Opcode.BINARY) {
					byte[] bodyBs = websocketPacket.getBody();
					if (bodyBs != null) {
						try {
							String text = new String(bodyBs, handshakeRequest.getCharset());
							websocketPacket.setWsBodyText(text);
						} catch (UnsupportedEncodingException e) {
							log.error(e.toString(), e);
						}
					}
				}
			}
		}
		return websocketPacket;
	}

	@Override
	public ByteBuffer encode(Packet packet, TioConfig tioConfig, ChannelContext channelContext) {
		if (packet == null) {
			return null;
		} else if (packet instanceof HttpResponse) {
			try {
				return HttpResponseEncoder.encode((HttpResponse) packet, tioConfig, channelContext);
			} catch (UnsupportedEncodingException e) {
				log.error(e.toString(), e);
				return null;
			}
		}
		// 处理 websocket 子协议
		WsResponse wsResponse;
		System.out.println(packet.getMeta());
		if (packet instanceof WsResponse) {
			wsResponse = (WsResponse) packet;
		} else {
			wsResponse = wsMsgHandler.encodeSubProtocol(packet, tioConfig, channelContext);
			Objects.requireNonNull(wsResponse, "IWsMsgHandler encodeSubProtocol WsResponse is null.");
		}
		// 握手包
		if (wsResponse.isHandShake()) {
			WsSessionContext imSessionContext = (WsSessionContext) channelContext.get();
			HttpResponse handshakeResponse = imSessionContext.getHandshakeResponse();
			try {
				return HttpResponseEncoder.encode(handshakeResponse, tioConfig, channelContext);
			} catch (UnsupportedEncodingException e) {
				log.error(e.toString(), e);
				return null;
			}
		}
		return WsServerEncoder.encode(wsResponse, tioConfig, channelContext);
	}

	private WsResponse handlerWs(WsRequest websocketPacket, byte[] bytes, Opcode opcode, ChannelContext channelContext) throws Exception {
		System.out.println(new String(bytes));
		if (opcode == Opcode.TEXT) {
			if (bytes == null || bytes.length == 0) {
				Tio.remove(channelContext, "错误的websocket包，body为空");
				return null;
			}
			String text = new String(bytes, httpConfig.getCharset());
			Object retObj = wsMsgHandler.onText(websocketPacket, text, channelContext);
			String methodName = "onText";
			return processRetObj(retObj, methodName, channelContext);
		} else if (opcode == Opcode.BINARY) {
			if (bytes == null || bytes.length == 0) {
				Tio.remove(channelContext, "错误的websocket包，body为空");
				return null;
			}
			Object retObj = wsMsgHandler.onBytes(websocketPacket, bytes, channelContext);
			String methodName = "onBytes";
			return processRetObj(retObj, methodName, channelContext);
		} else if (opcode == Opcode.PING || opcode == Opcode.PONG) {
			log.debug("收到{}", opcode);
			return null;
		} else if (opcode == Opcode.CLOSE) {
			Object retObj = wsMsgHandler.onClose(websocketPacket, bytes, channelContext);
			String methodName = "onClose";
			return processRetObj(retObj, methodName, channelContext);
		} else {
			Tio.remove(channelContext, "错误的websocket包，错误的Opcode");
			return null;
		}
	}

	@Override
	public void handler(Packet packet, ChannelContext channelContext) throws Exception {
		if (packet instanceof HttpRequest) {
			HttpRequest request = (HttpRequest) packet;
			String ip = request.getClientIp();
			if (channelContext.tioConfig.ipBlacklist.isInBlacklist(ip)) {
				HttpResponse httpResponse = request.httpConfig.getRespForBlackIp();
				if (httpResponse != null) {
					Tio.send(channelContext, httpResponse);
				} else {
					Tio.remove(channelContext, ip + "在黑名单中");
				}
				return;
			}
			HttpResponse httpResponse = requestHandler.handler(request);
			if (httpResponse != null) {
				Tio.send(channelContext, httpResponse);
			} else {
				if (log.isInfoEnabled()) {
					log.info("{}, {}, handler return null, request line: {}", channelContext.tioConfig.getName(), channelContext.toString(), request.getRequestLine().toString());
				}
				request.close("handler return null");
			}
			return;
		}
		WsRequest wsRequest = (WsRequest) packet;
		// 判断握手包
		if (wsRequest.isHandShake()) {
			WsSessionContext wsSessionContext = (WsSessionContext) channelContext.get();
			HttpRequest request = wsSessionContext.getHandshakeRequest();
			HttpResponse httpResponse = wsSessionContext.getHandshakeResponse();
			HttpResponse response = wsMsgHandler.handshake(request, httpResponse, channelContext);
			if (response == null) {
				Tio.remove(channelContext, "业务层不同意握手");
				return;
			}
			wsSessionContext.setHandshakeResponse(response);
			WsResponse wsResponse = new WsResponse();
			wsResponse.setHandShake(true);
			Tio.send(channelContext, wsResponse);
			wsSessionContext.setHandshaked(true);
			wsMsgHandler.onAfterHandshaked(request, httpResponse, channelContext);
			return;
		}
		if (!wsRequest.isWsEof()) {
			return;
		}
		WsResponse wsResponse = handlerWs(wsRequest, wsRequest.getBody(), wsRequest.getWsOpcode(), channelContext);
		if (wsResponse != null) {
			Tio.send(channelContext, wsResponse);
		}
	}

	private WsResponse processRetObj(Object obj, String methodName, ChannelContext channelContext) {
		if (obj == null) {
			return null;
		} else {
			if (obj instanceof String) {
				return WsResponse.fromText((String) obj, httpConfig.getCharset());
			} else if (obj instanceof byte[]) {
				return WsResponse.fromBytes((byte[]) obj);
			} else if (obj instanceof WsResponse) {
				return (WsResponse) obj;
			} else if (obj instanceof ByteBuffer) {
				return WsResponse.fromBytes(((ByteBuffer) obj).array());
			} else {
				log.error("{} {}.{}()方法，只允许返回byte[]、ByteBuffer、WsResponse或null，但是程序返回了{}", channelContext, this.getClass().getName(), methodName, obj.getClass().getName());
				return null;
			}
		}
	}

	/**
	 * 本方法改编自baseio: https://gitee.com/generallycloud/baseio<br>
	 * 感谢开源作者的付出
	 *
	 * @param request HttpRequest
	 * @return HttpResponse
	 * @author tanyaowu
	 */
	public HttpResponse updateWebSocketProtocol(HttpRequest request) throws TioDecodeException {
		Map<String, String> headers = request.getHeaders();
		String secWebSocketKey = headers.get(HttpConst.RequestHeaderKey.Sec_WebSocket_Key);
		if (StrUtil.isNotBlank(secWebSocketKey)) {
			byte[] secWebSocketKeyBytes;
			try {
				secWebSocketKeyBytes = secWebSocketKey.getBytes(request.getCharset());
			} catch (UnsupportedEncodingException e) {
				throw new TioDecodeException(e);
			}
			byte[] allBs = new byte[secWebSocketKeyBytes.length + SEC_WEBSOCKET_KEY_SUFFIX_BYTES.length];
			System.arraycopy(secWebSocketKeyBytes, 0, allBs, 0, secWebSocketKeyBytes.length);
			System.arraycopy(SEC_WEBSOCKET_KEY_SUFFIX_BYTES, 0, allBs, secWebSocketKeyBytes.length, SEC_WEBSOCKET_KEY_SUFFIX_BYTES.length);
			byte[] keyArray = SHA1Util.SHA1(allBs);
			String acceptKey = BASE64Util.byteArrayToBase64(keyArray);
			HttpResponse httpResponse = new HttpResponse(request);
			// 101 协议转换
			httpResponse.setStatus(HttpResponseStatus.C101);
			Map<HeaderName, HeaderValue> respHeaders = new HashMap<>();
			respHeaders.put(HeaderName.Connection, HeaderValue.Connection.Upgrade);
			respHeaders.put(HeaderName.Upgrade, HeaderValue.Upgrade.WebSocket);
			respHeaders.put(HeaderName.Sec_WebSocket_Accept, HeaderValue.from(acceptKey));
			// websocket 子协议协商
			String[] supportedSubProtocols = wsMsgHandler.getSupportedSubProtocols();
			if (supportedSubProtocols != null && supportedSubProtocols.length > 0) {
				String requestedSubProtocols = headers.get(SEC_WEBSOCKET_PROTOCOL);
				String selectSubProtocol = selectSubProtocol(requestedSubProtocols, supportedSubProtocols);
				if (selectSubProtocol != null) {
					respHeaders.put(HEADER_NAME_SEC_WEBSOCKET_PROTOCOL, HeaderValue.from(selectSubProtocol));
				}
			}
			httpResponse.addHeaders(respHeaders);
			return httpResponse;
		}
		return null;
	}

	/**
	 * Selects the first matching supported sub protocol
	 *
	 * @param requestedSubProtocols 请求中的子协议
	 * @param subProtocols          系统支持得子协议，注意：不支持 * 通配
	 * @return First matching supported sub protocol. Null if not found.
	 */
	private static String selectSubProtocol(String requestedSubProtocols, String[] subProtocols) {
		if (requestedSubProtocols == null || subProtocols == null || subProtocols.length == 0) {
			return null;
		}
		String[] requestedSubProtocolArray = requestedSubProtocols.split(",");
		for (String p : requestedSubProtocolArray) {
			String requestedSubProtocol = p.trim();
			for (String supportedSubProtocol : subProtocols) {
				if (requestedSubProtocol.equals(supportedSubProtocol)) {
					return requestedSubProtocol;
				}
			}
		}
		// No match found
		return null;
	}

}
