#include "threadpool.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <time.h>


void *thread_routine(void *arg)
{
   // struct timespec abstime;
   int timeout;
   printf("\n");
   printf("thread 0x%x is starting\n", (int) pthread_self());
   threadpool_t *pool = (threadpool_t *) arg;
   while (1)
   {
      timeout = 0;
      condition_lock(&pool->ready);
      pool->idle++;
      // 等待队列有任务到来或者线程池销毁通知
      while (pool->first == NULL && !pool->quit)
      {
         printf("thread 0x%x is waiting\n", (int) pthread_self());
         condition_wait(&pool->ready);
      }

      // 等待到条件，处于工作状态
      pool->idle--;

      // 等待到任务
      if (pool->first != NULL)
      {
         // 从队头取出任务
         task_t *t = pool->first;
         pool->first = t->next;
         // 执行任务需要一定的时间，所以要先解锁，以便生产者进程
         // 能够往队列中添加任务，其它消费者线程能够进入等待任务
         condition_unlock(&pool->ready);
         printf("thread 0x%x is working\n", (int) pthread_self());
         t->run(t->arg);
         printf("\n");
         printf("thread 0x%x work  done \n", (int) pthread_self());
         free(t);
         condition_lock(&pool->ready);
      }
      // 如果等待到线程池销毁通知, 且任务都执行完毕
      if (pool->quit && pool->first == NULL)
      {
         pool->counter--;
         if (pool->counter == 0)
            condition_signal(&pool->ready);

         condition_unlock(&pool->ready);
         // 跳出循环之前要记得解锁
         break;
      }

      if (timeout && pool->first == NULL)
      {
         pool->counter--;
         condition_unlock(&pool->ready);
         // 跳出循环之前要记得解锁
         break;
      }
      condition_unlock(&pool->ready);
   }

   printf("thread 0x%x is exting\n", (int) pthread_self());
   return NULL;

}


// 初始化线程池
void threadpool_init(
      threadpool_t *pool,
      int threads,
      tcl_t *tcl,
      tsl_t *tsl
)
{
   // 对线程池中的各个字段初始化
   condition_init(&pool->ready);
   pool->first = NULL;
   pool->last = NULL;
   pool->counter = 0;
   pool->idle = 0;
   pool->max_threads = threads;
   pool->quit = 0;

   tcl->first = NULL;
   tcl->last = NULL;
   tcl->count = 0;

   tsl->first = NULL;
   tsl->last = NULL;
   tsl->count = 0;
}


// 往线程池中添加任务
void threadpool_add_task(threadpool_t *pool, void *(*run)(void *arg), void *arg)
{
   // 生成新任务
   task_t *newtask = (task_t *) malloc(sizeof(task_t));
   newtask->run = run;
   newtask->arg = arg;
   newtask->next = NULL;

   condition_lock(&pool->ready);
   // 将任务添加到队列
   if (pool->first == NULL)
      pool->first = newtask;
   else
      pool->last->next = newtask;
   pool->last = newtask;

   // 如果有等待线程，则唤醒其中一个
   if (pool->idle > 0)
      condition_signal(&pool->ready);
   else if (pool->counter < pool->max_threads)
   {
      // 没有等待线程，并且当前线程数不超过最大线程数，则创建一个新线程
      pthread_t tid;
      pthread_create(&tid, NULL, thread_routine, pool);
      pool->counter++;
   }
   condition_unlock(&pool->ready);
}


// 销毁线程池
void threadpool_destroy(threadpool_t *pool)
{
   if (pool->quit)
   {
      return;
   }
   condition_lock(&pool->ready);
   pool->quit = 1;
   if (pool->counter > 0)
   {
      if (pool->idle > 0)
         condition_broadcast(&pool->ready);

      // 处于执行任务状态中的线程，不会收到广播
      // 线程池需要等待执行任务状态中的线程全部退出

      while (pool->counter > 0)
         condition_wait(&pool->ready);
   }
   condition_unlock(&pool->ready);
   condition_destroy(&pool->ready);
}