#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

/* 常量定义 */
#define THREAD_CONNECTIONS 10        // 最大线程数
#define MONITOR_INTERVAL 1           // 监控间隔(秒)

/* 线程状态枚举 */
typedef enum {
    THREAD_RUNNING,     // 0:运行中
    THREAD_STOPPED,     // 1:正常停止  
    THREAD_RESTARTING,  // 2:重启中
    THREAD_CRASHED      // 3:异常崩溃
} thread_state_t;

/* 线程控制结构体 */
typedef struct {
    pthread_t tid;          // 线程ID
    int index;              // 线程编号(0~CONNECTIONS-1)
    thread_state_t state;   // 当前状态
    pthread_mutex_t lock;   // 线程专用互斥锁
} thread_info_t;

/* 全局变量 */
thread_info_t thread_info[THREAD_CONNECTIONS];  // 线程信息数组
pthread_mutex_t global_lock = PTHREAD_MUTEX_INITIALIZER;  // 全局互斥锁

/* 线程工作函数 待分配线程池*/
void* work_thread(void* arg) {
    int index = *(int*)arg;  // 获取线程索引
    free(arg);  // 释放动态分配的索引内存

    // 更新线程状态为运行中
    pthread_mutex_lock(&thread_info[index].lock);
    printf("Thread %d started\n", index);
    thread_info[index].state = THREAD_RUNNING;
    pthread_mutex_unlock(&thread_info[index].lock);

    // 模拟工作循环(5秒间隔)
    while (1) {
        sleep(5);

        // 10%概率模拟线程故障
        if (rand() % 10 == 0) {
            pthread_mutex_lock(&thread_info[index].lock);
            printf("Thread %d simulated failure\n", index);
            pthread_mutex_unlock(&thread_info[index].lock);
            break;
        }
    }

    // 线程终止处理
    pthread_mutex_lock(&thread_info[index].lock);
    thread_info[index].state = THREAD_STOPPED;
    printf("Thread %d stopped\n", index);
    pthread_mutex_unlock(&thread_info[index].lock);
    return NULL;
}
/* 线程工作函数 1号子线程*/
void* work_thread_1(void* arg) {
    int index = *(int*)arg;  // 获取线程索引
    free(arg);  // 释放动态分配的索引内存

    // 更新线程状态为运行中
    pthread_mutex_lock(&thread_info[index].lock);
    printf("work_thread_1 %d started\n", index);
    thread_info[index].state = THREAD_RUNNING;
    pthread_mutex_unlock(&thread_info[index].lock);

    // 1号子线程正常运行循环
    while (1) {
        sleep(5);

        // 10%概率模拟线程故障
        if (rand() % 10 == 0) {
            pthread_mutex_lock(&thread_info[index].lock);
            printf("Thread %d simulated failure\n", index);
            pthread_mutex_unlock(&thread_info[index].lock);
            break;
        }
    }

    // 线程终止处理
    pthread_mutex_lock(&thread_info[index].lock);
    thread_info[index].state = THREAD_STOPPED;
    printf("work_thread_1 %d stopped\n", index);
    pthread_mutex_unlock(&thread_info[index].lock);
    return NULL;
}
/* 线程重启函数 */
void restart_thread(int index) {
    pthread_mutex_lock(&global_lock);
    if (thread_info[index].state == THREAD_RESTARTING) {
        pthread_mutex_unlock(&global_lock);
        return;  // 避免重复重启
    }

    thread_info[index].state = THREAD_RESTARTING;
    printf("Restarting thread %d\n", index);
    pthread_mutex_unlock(&global_lock);

    // 创建新线程
    int* new_index = (int*)malloc(sizeof(int));
    *new_index = index;

    if (index == 0) {
        //子线程1号重置
        if (pthread_create(&thread_info[index].tid, NULL, work_thread_1, new_index) != 0) {
            pthread_mutex_lock(&global_lock);
            printf("Failed to restart work_thread_1 %d\n", index);
            thread_info[index].state = THREAD_CRASHED;
            pthread_mutex_unlock(&global_lock);
            free(new_index);
        }
    }
    else {
        //待分配线程池重置
        if (pthread_create(&thread_info[index].tid, NULL, work_thread, new_index) != 0) {
            pthread_mutex_lock(&global_lock);
            printf("Failed to restart thread %d\n", index);
            thread_info[index].state = THREAD_CRASHED;
            pthread_mutex_unlock(&global_lock);
            free(new_index);
        }
    }
    
}

/* 线程存活检测 */
int is_thread_alive(pthread_t tid) {
    return pthread_tryjoin_np(tid, NULL) == EBUSY;  // EBUSY表示线程仍在运行
}

/* 主函数 */
int main1() {
    srand(time(NULL));  // 初始化随机数种子

    // 初始化线程数组
    for (int i = 0; i < THREAD_CONNECTIONS; i++) {
        thread_info[i].index = i;
        thread_info[i].state = THREAD_STOPPED;
        pthread_mutex_init(&thread_info[i].lock, NULL);  // 初始化每个线程的锁
    }

    // 创建初始线程组
    for (int i = 0; i < THREAD_CONNECTIONS; i++) {
        int* index = (int*)malloc(sizeof(int));
        *index = i;

        if (i == 0) {
            //子线程线程1号
            if (pthread_create(&thread_info[i].tid, NULL, work_thread_1, index) != 0) {
                printf("Failed to create work_thread_1 %d\n", i);
                free(index);
            }
        }
        else {
            //待分配线程池
            if (pthread_create(&thread_info[i].tid, NULL, work_thread, index) != 0) {
                printf("Failed to create thread %d\n", i);
                free(index);
            }
        }
    }

    printf("Thread monitoring system started with %d workers\n", THREAD_CONNECTIONS);

    // 主监控循环
    while (1) {
        sleep(MONITOR_INTERVAL);

        // 检查所有线程状态
        for (int i = 0; i < THREAD_CONNECTIONS; i++) {
            pthread_mutex_lock(&thread_info[i].lock);

            // 检测运行中线程是否崩溃
            if (thread_info[i].state == THREAD_RUNNING && !is_thread_alive(thread_info[i].tid)) {
                printf("Thread %d crashed unexpectedly\n", i);
                thread_info[i].state = THREAD_CRASHED;
            }

            // 处理需要重启的线程
            if (thread_info[i].state == THREAD_STOPPED || thread_info[i].state == THREAD_CRASHED) {
                pthread_mutex_unlock(&thread_info[i].lock);
                restart_thread(i);  // 异步重启
            }
            else {
                pthread_mutex_unlock(&thread_info[i].lock);
            }
        }
    }

    // 清理资源(理论上不会执行到这里)
    for (int i = 0; i < THREAD_CONNECTIONS; i++) {
        pthread_mutex_destroy(&thread_info[i].lock);
    }
    return 0;
}