#pragma once

#include <cstdint>

#include <string>

#include "envoy/event/dispatcher.h"

#include "envoy/singleton/instance.h"

#include "envoy/thread_local/thread_local.h"

#include "source/common/common/utility.h"

#include "date_provider.h"

namespace Envoy {

namespace Http {

/**

 * Base for all providers.

 */

class DateProviderImplBase : public DateProvider {

public:

  explicit DateProviderImplBase(TimeSource& time_source) : time_source_(time_source) {}

protected:

  TimeSource& time_source_;

};

/**

 * A caching thread local provider. This implementation updates the date string every 500ms and

 * caches on each thread.

 */

class TlsCachingDateProviderImpl : public DateProviderImplBase, public Singleton::Instance {

public:

  TlsCachingDateProviderImpl(Event::Dispatcher& dispatcher, ThreadLocal::SlotAllocator& tls);

  // Http::DateProvider

  void setDateHeader(ResponseHeaderMap& headers) override;

private:

  struct ThreadLocalCachedDate : public ThreadLocal::ThreadLocalObject {

    ThreadLocalCachedDate(const std::string& date_string) : date_string_(date_string) {}

    const std::string date_string_;

  };

  void onRefreshDate();

  ThreadLocal::SlotPtr tls_;

  Event::TimerPtr refresh_timer_;

};

/**

 * A basic provider that just creates the date string every time.

 */

class SlowDateProviderImpl : public DateProviderImplBase {

  using DateProviderImplBase::DateProviderImplBase;

public:

  // Http::DateProvider

  void setDateHeader(ResponseHeaderMap& headers) override;

};

} // namespace Http

} // namespace Envoy