package com.laker.admin.framework.ext.thread;

import cn.hutool.core.util.IdUtil;
import com.laker.admin.framework.EasyAdminConstants;
import com.laker.admin.framework.aop.trace.SpanType;
import com.laker.admin.framework.aop.trace.TraceContext;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.MDC;

import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.RunnableFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/**
 * 自定义扩展线程池用于捕获执行中异常，防止异常被吞 + 解决MDC参数问题。
 *
 * @author laker
 */
@Slf4j
public class EasyAdminMDCThreadPoolExecutor extends EasyAdminThreadPoolExecutor {
    /**
     * 简易线程池构造器
     *
     * @param poolSize  线程池大小,e.g:60
     * @param queueSize 等待队列,e.g:1000
     * @param prefix    线程名前缀,e.g:MCP-POOL
     */
    public EasyAdminMDCThreadPoolExecutor(int poolSize, int queueSize, String prefix) {
        super(poolSize, queueSize, prefix);
        // 非核心线程如果处于闲置状态超过该值，就会被销毁。如果设置allowCoreThreadTimeOut(true)，则会也作用于核心线程。
        this.allowCoreThreadTimeOut(true);
    }

    /**
     * submit Runnable callable 都会走这里，所以我们只需要改写这里即可。
     *
     * @param command
     */
    @Override
    public void execute(Runnable command) {
        if (command instanceof RunnableFuture) {
            // submit future
            super.execute(new EasyAdminFuture((RunnableFuture) command, MDC.getCopyOfContextMap()));
        } else {
            super.execute(wrapExecuteRunnable(command, MDC.getCopyOfContextMap()));
        }

    }


    /**
     * 封装任务，加入TraceId，无返回值
     *
     * @param runnable
     * @param threadContext
     * @return
     */
    private static Runnable wrapExecuteRunnable(final Runnable runnable, final Map<String, String> threadContext) {
        return () -> {
            if (threadContext == null) {
                MDC.clear();
            } else {
                MDC.setContextMap(threadContext);
            }
            setTraceIdIfAbsent();
            try {
                TraceContext.addSpan("subThread.executeRunnable", SpanType.Thread);
                runnable.run();
            } finally {
                TraceContext.stopSpan(1);
                MDC.clear();
            }
        };
    }

    private static class EasyAdminFuture<T> implements RunnableFuture<T> {
        private RunnableFuture<T> future;
        private Map<String, String> threadContext;

        public EasyAdminFuture(RunnableFuture<T> future, Map<String, String> threadContext) {
            this.future = future;
            this.threadContext = threadContext;
        }

        @Override
        public boolean cancel(boolean mayInterruptIfRunning) {
            return this.future.cancel(mayInterruptIfRunning);
        }

        @Override
        public boolean isCancelled() {
            return this.future.isCancelled();
        }

        @Override
        public boolean isDone() {
            return this.future.isDone();
        }

        @Override
        public T get() throws InterruptedException, ExecutionException {
            return this.future.get();
        }

        @Override
        public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
            return this.future.get(timeout, unit);
        }

        @Override
        public void run() {
            if (threadContext == null) {
                MDC.clear();
            } else {
                MDC.setContextMap(threadContext);
            }
            setTraceIdIfAbsent();
            try {
                TraceContext.addSpan("subThread.submitRunnableFuture", SpanType.Thread);
                future.run();
            } finally {
                TraceContext.stopSpan(1);
                MDC.clear();
            }

        }

    }


    /**
     * 如果traceId不存在，则设置一个随机的traceId
     * 这种场景主要用于后台定时任务类，没有前端生成traceID的情况。
     */
    private static void setTraceIdIfAbsent() {
        if (MDC.get(EasyAdminConstants.TRACE_ID) == null) {
            MDC.put(EasyAdminConstants.TRACE_ID, IdUtil.simpleUUID());
        }
    }
}