// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FEED_PROCESSOR_H_
#define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FEED_PROCESSOR_H_

#include <map>
#include <set>
#include <string>

#include "base/callback.h"
#include "base/file_path.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/scoped_vector.h"
#include "base/memory/weak_ptr.h"
#include "chrome/browser/chromeos/drive/drive_file_error.h"
#include "googleurl/src/gurl.h"

namespace google_apis {
class ResourceList;
}  // google_apis

namespace drive {

class DriveEntryProto;
class DriveResourceMetadata;

// DriveFeedProcessor is used to process feeds from WAPI (codename for
// Documents List API).
class DriveFeedProcessor {
 public:
  typedef std::map<std::string /* resource_id */, DriveEntryProto>
      DriveEntryProtoMap;

  // Class used to record UMA stats with FeedToEntryProtoMap().
  class FeedToEntryProtoMapUMAStats;

  explicit DriveFeedProcessor(DriveResourceMetadata* resource_metadata);
  ~DriveFeedProcessor();

  // Applies the documents feeds to the file system using |resource_metadata_|.
  //
  // |is_delta_feed| determines the type of feed to process, whether it is a
  // root feed (false) or a delta feed (true).
  //
  // In the case of processing the root feeds |root_feed_changestamp| is used
  // as its initial changestamp value. The value comes from
  // google_apis::AccountMetadataFeed.
  // |on_complete_callback| is run after the feed is applied.
  // |on_complete_callback| must not be null.
  // TODO(achuith): Change the type of on_complete_callback to
  // FileOperationCallback instead.
  void ApplyFeeds(
      const ScopedVector<google_apis::ResourceList>& feed_list,
      bool is_delta_feed,
      int64 root_feed_changestamp,
      const base::Closure& on_complete_callback);

  // Converts list of document feeds from collected feeds into a
  // DriveEntryProtoMap. |feed_changestamp| and/or |uma_stats| may be NULL.
  // entry_proto_map_ and root_upload_url_ are updated as side effects.
  void FeedToEntryProtoMap(
      const ScopedVector<google_apis::ResourceList>& feed_list,
      int64* feed_changestamp,
      FeedToEntryProtoMapUMAStats* uma_stats);

  // A map of DriveEntryProto's representing a feed.
  const DriveEntryProtoMap& entry_proto_map() const { return entry_proto_map_; }

  // The set of changed directories as a result of feed processing.
  const std::set<FilePath>& changed_dirs() const { return changed_dirs_; }

 private:
  // Applies the pre-processed feed from entry_proto_map_ onto the filesystem.
  void ApplyEntryProtoMap(bool is_delta_feed);

  // Apply the next item from entry_proto_map_ to the file system. The async
  // version posts to the message loop to avoid recursive stack-overflow.
  void ApplyNextEntryProto();
  void ApplyNextEntryProtoAsync();

  // Apply |entry_proto| to resource_metadata_.
  void ApplyEntryProto(const DriveEntryProto& entry_proto);

  // Continue ApplyEntryProto. This is a callback for
  // DriveResourceMetadata::GetEntryInfoByResourceId.
  void ContinueApplyEntryProto(
      const DriveEntryProto& entry_proto,
      DriveFileError error,
      const FilePath& file_path,
      scoped_ptr<DriveEntryProto> old_entry_proto);

  // Apply the DriveEntryProto pointed to by |it| to resource_metadata_.
  void ApplyNextByIterator(DriveEntryProtoMap::iterator it);

  // Helper function to add |entry_proto| to its parent. Updates changed_dirs_
  // as a side effect.
  void AddEntryToParent(const DriveEntryProto& entry_proto);

  // Callback for DriveResourceMetadata::AddEntryToParent.
  void NotifyForAddEntryToParent(bool is_directory,
                                 DriveFileError error,
                                 const FilePath& file_path);

  // Removes entry pointed to by |resource_id| from its parent. Updates
  // changed_dirs_ as a side effect.
  void RemoveEntryFromParent(
      const DriveEntryProto& entry_proto,
      const FilePath& file_path);

  // Continues RemoveEntryFromParent after
  // DriveResourceMetadata::GetChildDirectories.
  void OnGetChildrenForRemove(
      const DriveEntryProto& entry_proto,
      const FilePath& file_path,
      const std::set<FilePath>& child_directories);

  // Callback for DriveResourceMetadata::RemoveEntryFromParent.
  void NotifyForRemoveEntryFromParent(
      bool is_directory,
      const FilePath& file_path,
      const std::set<FilePath>& child_directories,
      DriveFileError error,
      const FilePath& parent_path);

  // Refreshes DriveResourceMetadata entry that has the same resource_id as
  // |entry_proto| with |entry_proto|. Updates changed_dirs_ as a side effect.
  void RefreshEntryProto(const DriveEntryProto& entry_proto,
                         const FilePath& file_path);

  // Callback for DriveResourceMetadata::RefreshEntryProto.
  void NotifyForRefreshEntryProto(
      const FilePath& old_file_path,
      DriveFileError error,
      const FilePath& file_path,
      scoped_ptr<DriveEntryProto> entry_proto);

  // Updates the upload url of the root directory with root_upload_url_.
  void UpdateRootUploadUrl();

  // Callback for DriveResourceMetadata::GetEntryInfoByPath for the root proto.
  // Updates root upload url in the root proto, and refreshes the proto.
  void OnGetRootEntryProto(DriveFileError error,
                           scoped_ptr<DriveEntryProto> root_proto);

  // Callback for DriveResourceMetadata::RefreshEntryProto after the root upload
  // url is set.
  void OnUpdateRootUploadUrl(DriveFileError error,
                             const FilePath& root_path,
                             scoped_ptr<DriveEntryProto> root_proto);

  // Runs after all entries have been processed.
  void OnComplete();

  // Reset the state of this object.
  void Clear();

  DriveResourceMetadata* resource_metadata_;  // Not owned.

  DriveEntryProtoMap entry_proto_map_;
  std::set<FilePath> changed_dirs_;
  GURL root_upload_url_;
  int64 largest_changestamp_;
  base::Closure on_complete_callback_;

  // Note: This should remain the last member so it'll be destroyed and
  // invalidate its weak pointers before any other members are destroyed.
  base::WeakPtrFactory<DriveFeedProcessor> weak_ptr_factory_;
  DISALLOW_COPY_AND_ASSIGN(DriveFeedProcessor);
};

}  // namespace drive

#endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FEED_PROCESSOR_H_