// Copyright 2016 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.

#include "chrome/browser/browsing_data/browsing_data_media_license_helper.h"

#include <memory>
#include <set>

#include "base/bind.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/sequenced_task_runner.h"
#include "base/task/post_task.h"
#include "chrome/browser/browsing_data/browsing_data_helper.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
#include "storage/browser/fileapi/file_system_context.h"
#include "storage/browser/fileapi/file_system_quota_util.h"
#include "storage/browser/fileapi/plugin_private_file_system_backend.h"
#include "storage/common/fileapi/file_system_types.h"

using content::BrowserThread;

namespace {

// An implementation of the BrowsingDataMediaLicenseHelper interface that
// determine data on media licenses in a given |filesystem_context| and
// returns a list of MediaLicenseInfo items to a client.
class BrowsingDataMediaLicenseHelperImpl
    : public BrowsingDataMediaLicenseHelper {
 public:
  // BrowsingDataMediaLicenseHelper implementation
  explicit BrowsingDataMediaLicenseHelperImpl(
      storage::FileSystemContext* filesystem_context);
  void StartFetching(const FetchCallback& callback) final;
  void DeleteMediaLicenseOrigin(const GURL& origin) final;

 private:
  ~BrowsingDataMediaLicenseHelperImpl() final;

  // Enumerates all filesystem files, storing the resulting list into
  // file_system_file_ for later use. This must be called on the file
  // task runner.
  void FetchMediaLicenseInfoOnFileTaskRunner(const FetchCallback& callback);

  // Deletes all file systems associated with |origin|. This must be called on
  // the file task runner.
  void DeleteMediaLicenseOriginOnFileTaskRunner(const GURL& origin);

  // Returns the file task runner for the |filesystem_context_|.
  base::SequencedTaskRunner* file_task_runner() {
    return filesystem_context_->default_file_task_runner();
  }

  // Keep a reference to the FileSystemContext object for the current profile
  // for use on the file task runner.
  scoped_refptr<storage::FileSystemContext> filesystem_context_;

  DISALLOW_COPY_AND_ASSIGN(BrowsingDataMediaLicenseHelperImpl);
};

BrowsingDataMediaLicenseHelperImpl::BrowsingDataMediaLicenseHelperImpl(
    storage::FileSystemContext* filesystem_context)
    : filesystem_context_(filesystem_context) {
  DCHECK(filesystem_context_.get());
}

BrowsingDataMediaLicenseHelperImpl::~BrowsingDataMediaLicenseHelperImpl() {}

void BrowsingDataMediaLicenseHelperImpl::StartFetching(
    const FetchCallback& callback) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  DCHECK(!callback.is_null());
  file_task_runner()->PostTask(
      FROM_HERE, base::BindOnce(&BrowsingDataMediaLicenseHelperImpl::
                                    FetchMediaLicenseInfoOnFileTaskRunner,
                                this, callback));
}

void BrowsingDataMediaLicenseHelperImpl::DeleteMediaLicenseOrigin(
    const GURL& origin) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  file_task_runner()->PostTask(
      FROM_HERE, base::BindOnce(&BrowsingDataMediaLicenseHelperImpl::
                                    DeleteMediaLicenseOriginOnFileTaskRunner,
                                this, origin));
}

void BrowsingDataMediaLicenseHelperImpl::FetchMediaLicenseInfoOnFileTaskRunner(
    const FetchCallback& callback) {
  DCHECK(file_task_runner()->RunsTasksInCurrentSequence());
  DCHECK(!callback.is_null());

  const storage::FileSystemType kType = storage::kFileSystemTypePluginPrivate;

  storage::PluginPrivateFileSystemBackend* backend =
      static_cast<storage::PluginPrivateFileSystemBackend*>(
          filesystem_context_->GetFileSystemBackend(kType));

  // Determine the set of origins used.
  std::set<GURL> origins;
  std::list<MediaLicenseInfo> result;
  backend->GetOriginsForTypeOnFileTaskRunner(kType, &origins);
  for (const GURL& origin : origins) {
    if (!BrowsingDataHelper::HasWebScheme(origin))
      continue;  // Non-websafe state is not considered browsing data.

    int64_t size;
    base::Time last_modified_time;
    backend->GetOriginDetailsOnFileTaskRunner(filesystem_context_.get(), origin,
                                              &size, &last_modified_time);
    result.push_back(MediaLicenseInfo(origin, size, last_modified_time));
  }

  base::PostTaskWithTraits(FROM_HERE, {BrowserThread::UI},
                           base::BindOnce(callback, result));
}

void BrowsingDataMediaLicenseHelperImpl::
    DeleteMediaLicenseOriginOnFileTaskRunner(const GURL& origin) {
  DCHECK(file_task_runner()->RunsTasksInCurrentSequence());

  const storage::FileSystemType kType = storage::kFileSystemTypePluginPrivate;
  storage::FileSystemBackend* backend =
      filesystem_context_->GetFileSystemBackend(kType);
  storage::FileSystemQuotaUtil* quota_util = backend->GetQuotaUtil();
  quota_util->DeleteOriginDataOnFileTaskRunner(
      filesystem_context_.get(), filesystem_context_->quota_manager_proxy(),
      origin, kType);
}

}  // namespace

BrowsingDataMediaLicenseHelper::MediaLicenseInfo::MediaLicenseInfo(
    const GURL& origin,
    int64_t size,
    base::Time last_modified_time)
    : origin(origin), size(size), last_modified_time(last_modified_time) {}

BrowsingDataMediaLicenseHelper::MediaLicenseInfo::MediaLicenseInfo(
    const MediaLicenseInfo& other) = default;

BrowsingDataMediaLicenseHelper::MediaLicenseInfo::~MediaLicenseInfo() {}

// static
BrowsingDataMediaLicenseHelper* BrowsingDataMediaLicenseHelper::Create(
    storage::FileSystemContext* filesystem_context) {
  return new BrowsingDataMediaLicenseHelperImpl(filesystem_context);
}