// 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 COMPONENTS_CONTEXTUAL_TASKS_PUBLIC_CONTEXTUAL_TASK_CONTEXT_H_
#define COMPONENTS_CONTEXTUAL_TASKS_PUBLIC_CONTEXTUAL_TASK_CONTEXT_H_

#include <string>
#include <vector>

#include "base/uuid.h"
#include "components/contextual_tasks/public/contextual_task.h"
#include "components/sessions/core/session_id.h"
#include "ui/gfx/image/image.h"
#include "url/gurl.h"

namespace url_deduplication {
class URLDeduplicationHelper;
}  // namespace url_deduplication

namespace contextual_tasks {

// Enum representing the different sources that can contribute to the context of
// a contextual task.
enum class ContextualTaskContextSource {
  kFallbackTitle,
  kFaviconService,
  kHistoryService,
  kUploadedContextDecorator,
  kSubmittedContextDecorator,
};

class ContextualTask;

// Data block for UrlAttachment, intended to be modified only by
// ContextDecorator implementations.
struct UrlAttachmentDecoratorData {
  UrlAttachmentDecoratorData();
  ~UrlAttachmentDecoratorData();
  UrlAttachmentDecoratorData(const UrlAttachmentDecoratorData&);
  UrlAttachmentDecoratorData& operator=(const UrlAttachmentDecoratorData&);
  UrlAttachmentDecoratorData(UrlAttachmentDecoratorData&&);
  UrlAttachmentDecoratorData& operator=(UrlAttachmentDecoratorData&&);

  // Filled in by ContextualTaskContextSource::kFallbackTitle.
  struct FallbackTitleData {
    std::u16string title;
  };
  FallbackTitleData fallback_title_data;

  // Filled in by ContextualTaskContextSource::kFaviconService.
  struct FaviconData {
    gfx::Image image;
    GURL icon_url;
  };
  FaviconData favicon_data;

  // Filled in by ContextualTaskContextSource::kHistoryService.
  struct HistoryData {
    std::u16string title;
  };
  HistoryData history_data;

  // Filled in by ContextualTaskContextSource::kUploadedContextDecorator and
  // ContextualTaskContextSource::kSubmittedContextDecorator.
  struct ContextualSearchContextData {
    std::u16string title;
    // From SessionTabHelper.
    SessionID tab_session_id = SessionID::InvalidValue();
  };
  ContextualSearchContextData contextual_search_context_data;
};

// Represents a URL that is attached to a `ContextualTask`. This struct contains
// the URL itself and a data block that can be populated by decorators.
struct UrlAttachment {
 public:
  explicit UrlAttachment(const GURL& url, ResourceType resource_type);
  ~UrlAttachment();

  UrlAttachment(const UrlAttachment&);
  UrlAttachment(UrlAttachment&&);
  UrlAttachment& operator=(const UrlAttachment&);
  UrlAttachment& operator=(UrlAttachment&&);

  // Accessor methods.
  GURL GetURL() const;
  std::u16string GetTitle() const;
  gfx::Image GetFavicon() const;
  // The tab SessionID of the tab that was the source of this attachment.
  SessionID GetTabSessionId() const;
  // True if the context/media is derived from a Chrome tab.
  bool HasChromeTabData() const;
  // The type of resource.
  ResourceType GetResourceType() const;

  // Gives access to internal data sources.
  UrlAttachmentDecoratorData& GetMutableDecoratorDataForTesting();

 private:
  friend class ContextDecorator;
  friend struct ContextualTaskContext;

  // ContextDecorator implementation can access this method through a protected
  // method.
  UrlAttachmentDecoratorData& GetMutableDecoratorData();

  // The URL that is attached.
  GURL url_;

  // The type of resource.
  ResourceType resource_type = ResourceType::kUnknown;

  // The title of the web page, if available from the ContextualTask directly.
  std::optional<std::u16string> title_;

  // The tab SessionID, if available from the ContextualTask directly.
  std::optional<SessionID> tab_session_id_;

  // True if the context/media is derived from a Chrome tab.
  bool has_chrome_tab_data_ = false;

  // A data block that can be populated by decorators with additional metadata
  // about the URL.
  UrlAttachmentDecoratorData decorator_data_;
};

// Represents the context associated with a `ContextualTask`. This is a
// snapshot of the context at a given point in time and is not kept in sync
// with the `ContextualTask`. It is passed through a chain of decorators to be
// enriched with additional metadata.
struct ContextualTaskContext {
 public:
  // Constructs a `ContextualTaskContext` from a `ContextualTask`.
  explicit ContextualTaskContext(const ContextualTask& task);
  ~ContextualTaskContext();

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

  // Returns the unique ID of the task this context is for.
  const base::Uuid& GetTaskId() const;

  // Returns the URL attachments for the task.
  const std::vector<UrlAttachment>& GetUrlAttachments() const;

  // Returns a deduplicated list of URL attachments for the task.
  // Meant to be used for context library.
  std::vector<UrlAttachment> GetUniqueUrlAttachments() const;

  // Returns a mutable version of the URL attachments for the task.
  std::vector<UrlAttachment>& GetMutableUrlAttachmentsForTesting();

  // Returns true if the given |url| is contained in the context.
  bool ContainsURL(
      const GURL& url,
      url_deduplication::URLDeduplicationHelper* deduplication_helper) const;

  // Returns a list of URL attachments that match the given |url|.
  std::vector<const UrlAttachment*> GetMatchingUrlAttachments(
      const GURL& url,
      url_deduplication::URLDeduplicationHelper* deduplication_helper) const;

 private:
  friend class ContextDecorator;

  // Returns a mutable version of the URL attachments for the task.
  std::vector<UrlAttachment>& GetMutableUrlAttachments();

  // The unique ID of the task this context is for.
  base::Uuid task_id_;

  // The URL attachments for the task.
  std::vector<UrlAttachment> urls_;
};

}  // namespace contextual_tasks

#endif  // COMPONENTS_CONTEXTUAL_TASKS_PUBLIC_CONTEXTUAL_TASK_CONTEXT_H_