#pragma once

#include <rwlock_traits.hpp>
#include <tpcc/stdlike/condition_variable.hpp>

#include <mutex>

namespace tpcc {
namespace solutions {

class ReaderWriterLock {
 public:

  // Reader section
  void ReaderLock() {
    std::unique_lock<std::mutex> lock (mutex_);
    while(write_acquire_ > 0) {
      cond_var_.wait(lock);
    }
    readers_++;
  }

  void ReaderUnlock() {
    std::unique_lock<std::mutex> lock (mutex_);
    readers_--;
    cond_var_.notify_all();
  }

  // Writer section
  void WriterLock() {
    std::unique_lock<std::mutex> lock (mutex_);
    write_acquire_++;
    while(readers_ > 0 || write_) {
      cond_var_.wait(lock);
    }
    write_ = true;
  }

  void WriterUnlock() {
    std::unique_lock<std::mutex> lock (mutex_);
    write_acquire_--;
    write_ = false;
    cond_var_.notify_all();
  }

  private:
    bool write_{false};
    size_t write_acquire_{0};
    size_t readers_{0};

    std::mutex mutex_;
    tpcc::condition_variable cond_var_;
};

} // namespace solutions
} // namespace tpcc