// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_HANDLE_IMPL_H_
#define CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_HANDLE_IMPL_H_

#include <atomic>

#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "content/browser/preloading/prefetch/prefetch_container_async_observer.h"
#include "content/public/browser/prefetch_handle.h"

namespace content {

class PrefetchContainer;
class PrefetchService;
enum class PrefetchStatus;

class PrefetchHandleImpl final : public PrefetchHandle {
 public:
  PrefetchHandleImpl(base::WeakPtr<PrefetchService> prefetch_service,
                     base::WeakPtr<PrefetchContainer> prefetch_container);
  ~PrefetchHandleImpl() override;

  // `PrefetchHandle` implementations
  void SetOnPrefetchHeadReceivedCallback(
      base::RepeatingCallback<void(const network::mojom::URLResponseHead&)>
          on_prefetch_head_received) override;
  void SetOnPrefetchCompletedOrFailedCallback(
      base::RepeatingCallback<
          void(const network::URLLoaderCompletionStatus& completion_status,
               const std::optional<int>& response_code)>
          on_prefetch_completed_or_failed) override;
  bool IsAlive() const override;
  bool IsPrefetchStale() const override;

  // TODO(crbug.com/390329781): The following methods are tentative interface
  // for incrementally migrating `//content/` internal code to `PrefetchHandle`.
  // Revisit the semantics when exposing for the public API.

  // Sets the `PrefetchStatus` that will be set to the `PrefetchContainer` when
  // this handle is destroyed and the `PrefetchContainer`'s `LoadState` is
  // `kStarted` at that time.
  void SetPrefetchStatusOnReleaseStartedPrefetch(
      PrefetchStatus prefetch_status_on_release_started_prefetch);

 protected:
  scoped_refptr<PrefetchStalenessAtomicState> GetStalenessAtomicState()
      const override;

 private:
  class PrefetchContainerObserverForCallback;

  // The `content::PrefetchContainerObserver` to be registered to
  // `PrefetchContainer`.
  PrefetchContainerObserver& GetObserver() const;
  // The underlying `PrefetchHandleImpl::PrefetchContainerObserver`, for setting
  // the callbacks.
  PrefetchContainerObserverForCallback& GetUnderlyingObserver() const;

  base::WeakPtr<PrefetchService> prefetch_service_;
  base::WeakPtr<PrefetchContainer> prefetch_container_;

  using AsyncObserverForCallback =
      PrefetchContainerAsyncObserver<PrefetchContainerObserverForCallback>;

  // Exactly one of these two is non-null, depending on
  // `features::kPrefetchAsyncPrefetchHandleCallback`.
  // TODO(crbug.com/480271813): Cleanup this once the feature is settled.
  std::unique_ptr<PrefetchContainerObserverForCallback>
      prefetch_container_observer_;
  std::unique_ptr<AsyncObserverForCallback> prefetch_container_async_observer_;

  scoped_refptr<PrefetchStalenessAtomicState> is_stale_;

  std::optional<PrefetchStatus> prefetch_status_on_release_started_prefetch_;
};

}  // namespace content

#endif  // CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_HANDLE_IMPL_H_