package com.xcong.excoin.modules.gateApi;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.xcong.excoin.modules.gateApi.wsHandler.GateChannelHandler;
import com.xcong.excoin.modules.okxNewPrice.utils.SSLConfig;
import lombok.extern.slf4j.Slf4j;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;

/**
 * Gate WebSocket 连接管理器。
 *
 * <h3>职责</h3>
 * 负责 TCP 连接的建立、维持和恢复。频道逻辑（订阅/解析）全部委托给 {@link GateChannelHandler} 实现类。
 *
 * <h3>生命周期</h3>
 * <pre>
 *   init()        → connect() → startHeartbeat()
 *   destroy()     → unsubscribe 所有 handler → closeBlocking() → shutdown 线程池
 *   onClose()     → reconnectWithBackoff() (最多 3 次，指数退避)
 * </pre>
 *
 * <h3>消息路由</h3>
 * <pre>
 *   onMessage → handleMessage:
 *     1. futures.pong         → cancelPongTimeout
 *     2. subscribe/unsubscribe → 日志
 *     3. error                → 错误日志
 *     4. update/all           → 遍历 channelHandlers → handler.handleMessage(response)
 * </pre>
 *
 * <h3>心跳机制</h3>
 * 采用双重检测：TCP 层的 WebSocket ping/pong + 应用层 futures.ping/futures.pong。
 * 10 秒未收到任何消息 → 发送 futures.ping；25 秒周期检查。
 *
 * <h3>线程安全</h3>
 * 连接状态用 AtomicBoolean（isConnected, isConnecting, isInitialized）。
 * 消息时间戳用 AtomicReference。心跳任务用 synchronized 保护。
 *
 * @author Administrator
 */
@Slf4j
public class GateKlineWebSocketClient {

    private static final String FUTURES_PING = "futures.ping";
    private static final String FUTURES_PONG = "futures.pong";
    private static final int HEARTBEAT_TIMEOUT = 10;

    /** WebSocket 地址，由 GateConfig 提供 */
    private final String wsUrl;

    /** Java-WebSocket 客户端实例 */
    private WebSocketClient webSocketClient;
    /** 心跳检测调度器 */
    private ScheduledExecutorService heartbeatExecutor;
    /** 心跳超时 Future */
    private volatile ScheduledFuture<?> pongTimeoutFuture;
    /** 最后收到消息的时间戳（毫秒） */
    private final AtomicReference<Long> lastMessageTime = new AtomicReference<>(System.currentTimeMillis());

    /** 连接状态 */
    private final AtomicBoolean isConnected = new AtomicBoolean(false);
    /** 连接中标记，防重入 */
    private final AtomicBoolean isConnecting = new AtomicBoolean(false);
    /** 初始化标记，防重复 init */
    private final AtomicBoolean isInitialized = new AtomicBoolean(false);

    /** 频道处理器列表，通过 addChannelHandler 注册 */
    private final List<GateChannelHandler> channelHandlers = new ArrayList<>();

    /** 重连等异步任务的缓存线程池（daemon 线程） */
    private final ExecutorService sharedExecutor = Executors.newCachedThreadPool(r -> {
        Thread t = new Thread(r, "gate-ws-worker");
        t.setDaemon(true);
        return t;
    });

    public GateKlineWebSocketClient(String wsUrl) {
        this.wsUrl = wsUrl;
    }

    /**
     * 注册频道处理器。需在 init() 前调用。
     */
    public void addChannelHandler(GateChannelHandler handler) {
        channelHandlers.add(handler);
    }

    /**
     * 初始化：建立 WebSocket 连接 → 启动心跳。
     */
    public void init() {
        if (!isInitialized.compareAndSet(false, true)) {
            log.warn("[WS] already init, skip");
            return;
        }
        connect();
        startHeartbeat();
    }

    /**
     * 销毁：取消订阅 → 关闭连接 → 关闭线程池。
     * <p>注意：先 closeBlocking 再 shutdown sharedExecutor，
     * 避免 onClose 回调中的 reconnectWithBackoff 访问已关闭的线程池。
     */
    public void destroy() {
        log.info("[WS] destroy...");

        if (webSocketClient != null && webSocketClient.isOpen()) {
            for (GateChannelHandler handler : channelHandlers) {
                handler.unsubscribe(webSocketClient);
            }
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                log.warn("[WS] unsubscribe wait interrupted");
            }
        }

        if (webSocketClient != null && webSocketClient.isOpen()) {
            try {
                webSocketClient.closeBlocking();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                log.warn("[WS] close interrupted");
            }
        }

        if (sharedExecutor != null && !sharedExecutor.isShutdown()) {
            sharedExecutor.shutdown();
        }

        shutdownExecutorGracefully(heartbeatExecutor);
        if (pongTimeoutFuture != null) {
            pongTimeoutFuture.cancel(true);
        }
        shutdownExecutorGracefully(sharedExecutor);

        log.info("[WS] destroyed");
    }

    /**
     * 建立 WebSocket 连接。使用 SSLContext 配置 TLS 协议。
     * 连接成功后依次订阅所有已注册的频道处理器。
     */
    private void connect() {
        if (isConnecting.get() || !isConnecting.compareAndSet(false, true)) {
            log.info("[WS] already connecting");
            return;
        }
        try {
            SSLConfig.configureSSL();
            System.setProperty("https.protocols", "TLSv1.2,TLSv1.3");
            URI uri = new URI(wsUrl);
            if (webSocketClient != null) {
                try { webSocketClient.closeBlocking(); } catch (InterruptedException e) { Thread.currentThread().interrupt(); }
            }
            webSocketClient = new WebSocketClient(uri) {
                @Override
                public void onOpen(ServerHandshake handshake) {
                    log.info("[WS] connected");
                    isConnected.set(true);
                    isConnecting.set(false);
                    if (sharedExecutor != null && !sharedExecutor.isShutdown()) {
                        resetHeartbeatTimer();
                        for (GateChannelHandler handler : channelHandlers) {
                            handler.subscribe(webSocketClient);
                        }
                        sendPing();
                    } else {
                        log.warn("[WS] shutting down, ignore onOpen");
                    }
                }

                @Override
                public void onMessage(String message) {
                    lastMessageTime.set(System.currentTimeMillis());
                    handleMessage(message);
                    resetHeartbeatTimer();
                }

                @Override
                public void onClose(int code, String reason, boolean remote) {
                    log.warn("[WS] closed, code:{}, reason:{}", code, reason);
                    isConnected.set(false);
                    isConnecting.set(false);
                    cancelPongTimeout();
                    if (sharedExecutor != null && !sharedExecutor.isShutdown() && !sharedExecutor.isTerminated()) {
                        sharedExecutor.execute(() -> {
                            try { reconnectWithBackoff(); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } catch (Exception e) { log.error("[WS] reconnect fail", e); }
                        });
                    } else {
                        log.warn("[WS] executor closed, no reconnect");
                    }
                }

                @Override
                public void onError(Exception ex) {
                    log.error("[WS] error", ex);
                    isConnected.set(false);
                }
            };
            webSocketClient.connect();
        } catch (URISyntaxException e) {
            log.error("[WS] bad uri", e);
            isConnecting.set(false);
        }
    }

    /**
     * 消息分发：先处理系统事件（pong/subscribe/error），
     * 再把 update/all 事件路由到各 channelHandler。
     * <p>每个 handler 内部通过 channel 名称做二次匹配，匹配成功返回 true 则停止遍历。
     */
    private void handleMessage(String message) {
        try {
            JSONObject response = JSON.parseObject(message);
            String channel = response.getString("channel");
            String event = response.getString("event");

            if (FUTURES_PONG.equals(channel)) {
                log.debug("[WS] pong received");
                cancelPongTimeout();
                return;
            }
            if ("subscribe".equals(event)) {
                log.info("[WS] {} subscribed: {}", channel, response.getJSONObject("result"));
                return;
            }
            if ("unsubscribe".equals(event)) {
                log.info("[WS] {} unsubscribed", channel);
                return;
            }
            if ("error".equals(event)) {
                JSONObject error = response.getJSONObject("error");
                log.error("[WS] {} error, code:{}, msg:{}",
                        channel,
                        error != null ? error.getInteger("code") : "N/A",
                        error != null ? error.getString("message") : response.getString("msg"));
                return;
            }
            if ("update".equals(event) || "all".equals(event)) {
                for (GateChannelHandler handler : channelHandlers) {
                    if (handler.handleMessage(response)) return;
                }
            }
        } catch (Exception e) {
            log.error("[WS] handle msg fail: {}", message, e);
        }
    }

    // ---- heartbeat ----

    private void startHeartbeat() {
        if (heartbeatExecutor != null && !heartbeatExecutor.isTerminated()) heartbeatExecutor.shutdownNow();
        heartbeatExecutor = Executors.newSingleThreadScheduledExecutor(r -> { Thread t = new Thread(r, "gate-ws-heartbeat"); t.setDaemon(true); return t; });
        heartbeatExecutor.scheduleWithFixedDelay(this::checkHeartbeatTimeout, 25, 25, TimeUnit.SECONDS);
    }

    private synchronized void resetHeartbeatTimer() {
        cancelPongTimeout();
        if (heartbeatExecutor != null && !heartbeatExecutor.isShutdown()) {
            pongTimeoutFuture = heartbeatExecutor.schedule(this::checkHeartbeatTimeout, HEARTBEAT_TIMEOUT, TimeUnit.SECONDS);
        }
    }

    private void checkHeartbeatTimeout() {
        if (!isConnected.get()) return;
        if (System.currentTimeMillis() - lastMessageTime.get() >= HEARTBEAT_TIMEOUT * 1000L) sendPing();
    }

    private void sendPing() {
        try {
            if (webSocketClient != null && webSocketClient.isOpen()) {
                JSONObject pingMsg = new JSONObject();
                pingMsg.put("time", System.currentTimeMillis() / 1000);
                pingMsg.put("channel", FUTURES_PING);
                webSocketClient.send(pingMsg.toJSONString());
                log.debug("[WS] ping sent");
            }
        } catch (Exception e) { log.warn("[WS] ping fail", e); }
    }

    private synchronized void cancelPongTimeout() {
        if (pongTimeoutFuture != null && !pongTimeoutFuture.isDone()) pongTimeoutFuture.cancel(true);
    }

    // ---- reconnect ----

    private void reconnectWithBackoff() throws InterruptedException {
        int attempt = 0, maxAttempts = 3;
        long delayMs = 5000;
        while (attempt < maxAttempts) {
            try { Thread.sleep(delayMs); connect(); return; } catch (Exception e) { log.warn("[WS] reconnect attempt {} fail", attempt + 1, e); delayMs *= 2; attempt++; }
        }
        log.error("[WS] reconnect exhausted after {} attempts", maxAttempts);
    }

    private void shutdownExecutorGracefully(ExecutorService executor) {
        if (executor == null || executor.isTerminated()) return;
        try { executor.shutdown(); if (!executor.awaitTermination(5, TimeUnit.SECONDS)) executor.shutdownNow(); }
        catch (InterruptedException e) { Thread.currentThread().interrupt(); executor.shutdownNow(); }
    }
}