// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_RESOURCE_ATTRIBUTION_WORKER_CONTEXT_H_
#define COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_RESOURCE_ATTRIBUTION_WORKER_CONTEXT_H_

#include <compare>
#include <optional>
#include <string>
#include <utility>

#include "base/memory/weak_ptr.h"
#include "third_party/blink/public/common/tokens/tokens.h"

namespace performance_manager {
class WorkerNode;
}  // namespace performance_manager

namespace resource_attribution {

class WorkerContext {
 public:
  ~WorkerContext();

  WorkerContext(const WorkerContext& other);
  WorkerContext& operator=(const WorkerContext& other);
  WorkerContext(WorkerContext&& other);
  WorkerContext& operator=(WorkerContext&& other);

  // UI thread methods.

  // Returns the WorkerContext for `token`. Returns nullopt if the WorkerToken
  // is not registered with PerformanceManager.
  static std::optional<WorkerContext> FromWorkerToken(
      const blink::WorkerToken& token);

  // Returns the WorkerToken for this context.
  blink::WorkerToken GetWorkerToken() const;

  // Returns the WorkerNode for this context, or a null WeakPtr if it no longer
  // exists.
  base::WeakPtr<performance_manager::WorkerNode> GetWeakWorkerNode() const;

  // PM sequence methods.

  // Returns the WorkerContext for `node`. Equivalent to
  // node->GetResourceContext().
  static WorkerContext FromWorkerNode(
      const performance_manager::WorkerNode* node);

  // Returns the WorkerContext for `node`, or nullopt if `node` is null.
  static std::optional<WorkerContext> FromWeakWorkerNode(
      base::WeakPtr<performance_manager::WorkerNode> node);

  // Returns the WorkerNode for this context, or nullptr if it no longer exists.
  performance_manager::WorkerNode* GetWorkerNode() const;

  // Returns a string representation of the context for debugging. This matches
  // the interface of base::TokenType and base::UnguessableToken, for
  // convenience.
  std::string ToString() const;

  // Compare WorkerContexts by WorkerToken.
  constexpr friend auto operator<=>(const WorkerContext& a,
                                    const WorkerContext& b) {
    return a.token_ <=> b.token_;
  }

  // Test WorkerContexts for equality by WorkerToken.
  constexpr friend bool operator==(const WorkerContext& a,
                                   const WorkerContext& b) {
    return a.token_ == b.token_;
  }

  // Add WorkerContexts to absl hashes.
  template <typename H>
  friend H AbslHashValue(H h, const WorkerContext& c) {
    return H::combine(std::move(h), c.token_);
  }

 private:
  WorkerContext(const blink::WorkerToken& token,
                base::WeakPtr<performance_manager::WorkerNode> weak_node);

  blink::WorkerToken token_;
  base::WeakPtr<performance_manager::WorkerNode> weak_node_;
};

}  // namespace resource_attribution

#endif  // COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_RESOURCE_ATTRIBUTION_WORKER_CONTEXT_H_