#ifndef THREAD_POOL_H_
#define THREAD_POOL_H_

#include<condition_variable>
#include<functional>
#include<thread>
#include<mutex>
#include<queue>

class ThreadPool
{
public:
   // Initialize thread pool and start workers.
   explicit ThreadPool(int thread_count);

   // Cleanup workers.
   ~ThreadPool();

   // Add a function to work queue.
   void Add(std::function<void()> &&func);

private:
   // Take work off of work_queue_ and run it.
   void WorkerThread();

   // Worker threads.
   std::vector<std::thread> workers_;

   // Work to be done.
   std::queue<std::function<void()>> work_queue_;

   // True if it's time for worker threads to exit.
   bool end_workers_ = false;

   // Condition to watch for work_queue_ and end_workers_ changes.
   std::condition_variable cv_;

   // One mutex for everything.
   std::mutex mu_;
};

#endif  // THREAD_POOL_H_