// Copyright 2013 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/chromeos/file_manager/volume_manager.h"

#include "base/basictypes.h"
#include "base/bind.h"
#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/memory/singleton.h"
#include "base/prefs/pref_service.h"
#include "chrome/browser/chromeos/drive/drive_integration_service.h"
#include "chrome/browser/chromeos/drive/file_errors.h"
#include "chrome/browser/chromeos/drive/file_system_interface.h"
#include "chrome/browser/chromeos/drive/file_system_util.h"
#include "chrome/browser/chromeos/file_manager/mounted_disk_monitor.h"
#include "chrome/browser/chromeos/file_manager/path_util.h"
#include "chrome/browser/chromeos/file_manager/volume_manager_factory.h"
#include "chrome/browser/chromeos/file_manager/volume_manager_observer.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/pref_names.h"
#include "chromeos/dbus/cros_disks_client.h"
#include "chromeos/disks/disk_mount_manager.h"
#include "content/public/browser/browser_thread.h"
#include "webkit/browser/fileapi/external_mount_points.h"

namespace file_manager {
namespace {

// Called on completion of MarkCacheFileAsUnmounted.
void OnMarkCacheFileAsUnmounted(drive::FileError error) {
  // Do nothing.
}

VolumeType MountTypeToVolumeType(
    chromeos::MountType type) {
  switch (type) {
    case chromeos::MOUNT_TYPE_INVALID:
      // We don't expect this value, but list here, so that when any value
      // is added to the enum definition but this is not edited, the compiler
      // warns it.
      break;
    case chromeos::MOUNT_TYPE_DEVICE:
      return VOLUME_TYPE_REMOVABLE_DISK_PARTITION;
    case chromeos::MOUNT_TYPE_ARCHIVE:
      return VOLUME_TYPE_MOUNTED_ARCHIVE_FILE;
  }

  NOTREACHED();
  return VOLUME_TYPE_DOWNLOADS_DIRECTORY;
}

// Returns a string representation of the given volume type.
std::string VolumeTypeToString(VolumeType type) {
  switch (type) {
    case VOLUME_TYPE_GOOGLE_DRIVE:
      return "drive";
    case VOLUME_TYPE_DOWNLOADS_DIRECTORY:
      return "downloads";
    case VOLUME_TYPE_REMOVABLE_DISK_PARTITION:
      return "removable";
    case VOLUME_TYPE_MOUNTED_ARCHIVE_FILE:
      return "archive";
  }
  NOTREACHED();
  return "";
}

// Generates a unique volume ID for the given volume info.
std::string GenerateVolumeId(const VolumeInfo& volume_info) {
  // For the same volume type, base names are unique, as mount points are
  // flat for the same volume type.
  return (VolumeTypeToString(volume_info.type) + ":" +
          volume_info.mount_path.BaseName().AsUTF8Unsafe());
}

// Returns the VolumeInfo for Drive file system.
VolumeInfo CreateDriveVolumeInfo() {
  const base::FilePath& drive_path = drive::util::GetDriveMountPointPath();

  VolumeInfo volume_info;
  volume_info.type = VOLUME_TYPE_GOOGLE_DRIVE;
  volume_info.device_type = chromeos::DEVICE_TYPE_UNKNOWN;
  volume_info.source_path = drive_path;
  volume_info.mount_path = drive_path;
  volume_info.mount_condition = chromeos::disks::MOUNT_CONDITION_NONE;
  volume_info.is_parent = false;
  volume_info.is_read_only = false;
  volume_info.volume_id = GenerateVolumeId(volume_info);
  return volume_info;
}

VolumeInfo CreateDownloadsVolumeInfo(
    const base::FilePath& downloads_path) {
  VolumeInfo volume_info;
  volume_info.type = VOLUME_TYPE_DOWNLOADS_DIRECTORY;
  volume_info.device_type = chromeos::DEVICE_TYPE_UNKNOWN;
  // Keep source_path empty.
  volume_info.mount_path = downloads_path;
  volume_info.mount_condition = chromeos::disks::MOUNT_CONDITION_NONE;
  volume_info.is_parent = false;
  volume_info.is_read_only = false;
  volume_info.volume_id = GenerateVolumeId(volume_info);
  return volume_info;
}

VolumeInfo CreateVolumeInfoFromMountPointInfo(
    const chromeos::disks::DiskMountManager::MountPointInfo& mount_point,
    const chromeos::disks::DiskMountManager::Disk* disk) {
  VolumeInfo volume_info;
  volume_info.type = MountTypeToVolumeType(mount_point.mount_type);
  volume_info.source_path = base::FilePath(mount_point.source_path);
  volume_info.mount_path = base::FilePath(mount_point.mount_path);
  volume_info.mount_condition = mount_point.mount_condition;
  if (disk) {
    volume_info.device_type = disk->device_type();
    volume_info.system_path_prefix =
        base::FilePath(disk->system_path_prefix());
    volume_info.drive_label = disk->drive_label();
    volume_info.is_parent = disk->is_parent();
    volume_info.is_read_only = disk->is_read_only();
  } else {
    volume_info.device_type = chromeos::DEVICE_TYPE_UNKNOWN;
    volume_info.is_parent = false;
    volume_info.is_read_only = false;
  }
  volume_info.volume_id = GenerateVolumeId(volume_info);

  return volume_info;
}

}  // namespace

VolumeInfo::VolumeInfo() {
}

VolumeInfo::~VolumeInfo() {
}

VolumeManager::VolumeManager(
    Profile* profile,
    drive::DriveIntegrationService* drive_integration_service,
    chromeos::PowerManagerClient* power_manager_client,
    chromeos::disks::DiskMountManager* disk_mount_manager)
    : profile_(profile),
      drive_integration_service_(drive_integration_service),
      disk_mount_manager_(disk_mount_manager),
      mounted_disk_monitor_(
          new MountedDiskMonitor(power_manager_client, disk_mount_manager)) {
  DCHECK(disk_mount_manager);
}

VolumeManager::~VolumeManager() {
}

VolumeManager* VolumeManager::Get(content::BrowserContext* context) {
  return VolumeManagerFactory::Get(context);
}

void VolumeManager::Initialize() {
  // Path to mount user folders have changed several times. We need to migrate
  // the old preferences on paths to the new format when needed. For the detail,
  // see the comments in file_manager::util::MigratePathFromOldFormat,
  // TODO(kinaba): Remove this are several rounds of releases.
  const char* kPathPreference[] = {
      prefs::kDownloadDefaultDirectory,
      prefs::kSelectFileLastDirectory,
      prefs::kSaveFileDefaultDirectory,
  };
  for (size_t i = 0; i < arraysize(kPathPreference); ++i) {
    const base::FilePath old_path =
        profile_->GetPrefs()->GetFilePath(kPathPreference[i]);
    base::FilePath new_path;
    if (!old_path.empty() &&
        file_manager::util::MigratePathFromOldFormat(profile_,
                                                     old_path, &new_path)) {
      profile_->GetPrefs()->SetFilePath(kPathPreference[i], new_path);
    }
  }

  // Register 'Downloads' folder for the profile to the file system.
  fileapi::ExternalMountPoints* mount_points =
      content::BrowserContext::GetMountPoints(profile_);
  DCHECK(mount_points);

  const base::FilePath downloads_folder =
      file_manager::util::GetDownloadsFolderForProfile(profile_);
  bool success = mount_points->RegisterFileSystem(
      downloads_folder.BaseName().AsUTF8Unsafe(),
      fileapi::kFileSystemTypeNativeLocal,
      downloads_folder);
  DCHECK(success);

  // Subscribe to DriveIntegrationService.
  if (drive_integration_service_)
    drive_integration_service_->AddObserver(this);

  // Subscribe to DiskMountManager.
  disk_mount_manager_->AddObserver(this);
  disk_mount_manager_->RequestMountInfoRefresh();

  // Subscribe to Profile Preference change.
  pref_change_registrar_.Init(profile_->GetPrefs());
  pref_change_registrar_.Add(
      prefs::kExternalStorageDisabled,
      base::Bind(&VolumeManager::OnExternalStorageDisabledChanged,
                 base::Unretained(this)));
}

void VolumeManager::Shutdown() {
  pref_change_registrar_.RemoveAll();
  disk_mount_manager_->RemoveObserver(this);

  if (drive_integration_service_)
    drive_integration_service_->RemoveObserver(this);
}

void VolumeManager::AddObserver(VolumeManagerObserver* observer) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DCHECK(observer);
  observers_.AddObserver(observer);
}

void VolumeManager::RemoveObserver(VolumeManagerObserver* observer) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DCHECK(observer);
  observers_.RemoveObserver(observer);
}

std::vector<VolumeInfo> VolumeManager::GetVolumeInfoList() const {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

  std::vector<VolumeInfo> result;

  // Adds "Drive" volume.
  if (drive_integration_service_ && drive_integration_service_->IsMounted())
    result.push_back(CreateDriveVolumeInfo());

  // Adds "Downloads".
  // Usually, the path of the directory is where we registered in Initialize(),
  // but in tests, the mount point may be overridden. To take it into account,
  // here we explicitly retrieves the path from the file API mount points.
  fileapi::ExternalMountPoints* fileapi_mount_points =
      content::BrowserContext::GetMountPoints(profile_);
  DCHECK(fileapi_mount_points);
  base::FilePath downloads;
  if (fileapi_mount_points->GetRegisteredPath("Downloads", &downloads))
    result.push_back(CreateDownloadsVolumeInfo(downloads));

  // Adds disks (both removable disks and zip archives).
  const chromeos::disks::DiskMountManager::MountPointMap& mount_points =
      disk_mount_manager_->mount_points();
  for (chromeos::disks::DiskMountManager::MountPointMap::const_iterator it =
           mount_points.begin();
       it != mount_points.end(); ++it) {
    result.push_back(CreateVolumeInfoFromMountPointInfo(
        it->second,
        disk_mount_manager_->FindDiskBySourcePath(it->second.source_path)));
  }

  return result;
}

bool VolumeManager::FindVolumeInfoById(const std::string& volume_id,
                                       VolumeInfo* result) const {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DCHECK(result);

  std::vector<VolumeInfo> info_list = GetVolumeInfoList();
  for (size_t i = 0; i < info_list.size(); ++i) {
    if (info_list[i].volume_id == volume_id) {
      *result = info_list[i];
      return true;
    }
  }

  return false;
}

void VolumeManager::OnFileSystemMounted() {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

  // Raise mount event.
  // We can pass chromeos::MOUNT_ERROR_NONE even when authentication is failed
  // or network is unreachable. These two errors will be handled later.
  VolumeInfo volume_info = CreateDriveVolumeInfo();
  FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                    OnVolumeMounted(chromeos::MOUNT_ERROR_NONE,
                                    volume_info,
                                    false));  // Not remounting.
}

void VolumeManager::OnFileSystemBeingUnmounted() {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

  VolumeInfo volume_info = CreateDriveVolumeInfo();
  FOR_EACH_OBSERVER(
      VolumeManagerObserver, observers_,
      OnVolumeUnmounted(chromeos::MOUNT_ERROR_NONE, volume_info));
}

void VolumeManager::OnDiskEvent(
    chromeos::disks::DiskMountManager::DiskEvent event,
    const chromeos::disks::DiskMountManager::Disk* disk) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));

  // Disregard hidden devices.
  if (disk->is_hidden())
    return;

  switch (event) {
    case chromeos::disks::DiskMountManager::DISK_ADDED: {
      if (disk->device_path().empty()) {
        DVLOG(1) << "Empty system path for " << disk->device_path();
        return;
      }

      bool mounting = false;
      if (disk->mount_path().empty() && disk->has_media() &&
          !profile_->GetPrefs()->GetBoolean(prefs::kExternalStorageDisabled)) {
        // If disk is not mounted yet and it has media and there is no policy
        // forbidding external storage, give it a try.
        // Initiate disk mount operation. MountPath auto-detects the filesystem
        // format if the second argument is empty. The third argument (mount
        // label) is not used in a disk mount operation.
        disk_mount_manager_->MountPath(
            disk->device_path(), std::string(), std::string(),
            chromeos::MOUNT_TYPE_DEVICE);
        mounting = true;
      }

      // Notify to observers.
      FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                        OnDiskAdded(*disk, mounting));
      return;
    }

    case chromeos::disks::DiskMountManager::DISK_REMOVED:
      // If the disk is already mounted, unmount it.
      if (!disk->mount_path().empty()) {
        disk_mount_manager_->UnmountPath(
            disk->mount_path(),
            chromeos::UNMOUNT_OPTIONS_LAZY,
            chromeos::disks::DiskMountManager::UnmountPathCallback());
      }

      // Notify to observers.
      FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                        OnDiskRemoved(*disk));
      return;

    case chromeos::disks::DiskMountManager::DISK_CHANGED:
      DVLOG(1) << "Ignore CHANGED event.";
      return;
  }
  NOTREACHED();
}

void VolumeManager::OnDeviceEvent(
    chromeos::disks::DiskMountManager::DeviceEvent event,
    const std::string& device_path) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DVLOG(1) << "OnDeviceEvent: " << event << ", " << device_path;

  switch (event) {
    case chromeos::disks::DiskMountManager::DEVICE_ADDED:
      FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                        OnDeviceAdded(device_path));
      return;
    case chromeos::disks::DiskMountManager::DEVICE_REMOVED:
      FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                        OnDeviceRemoved(device_path));
      return;
    case chromeos::disks::DiskMountManager::DEVICE_SCANNED:
      DVLOG(1) << "Ignore SCANNED event: " << device_path;
      return;
  }
  NOTREACHED();
}

void VolumeManager::OnMountEvent(
    chromeos::disks::DiskMountManager::MountEvent event,
    chromeos::MountError error_code,
    const chromeos::disks::DiskMountManager::MountPointInfo& mount_info) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DCHECK_NE(chromeos::MOUNT_TYPE_INVALID, mount_info.mount_type);

  if (mount_info.mount_type == chromeos::MOUNT_TYPE_ARCHIVE) {
    // If the file is not mounted now, tell it to drive file system so that
    // it can handle file caching correctly.
    // Note that drive file system knows if the file is managed by drive file
    // system or not, so here we report all paths.
    if ((event == chromeos::disks::DiskMountManager::MOUNTING &&
         error_code != chromeos::MOUNT_ERROR_NONE) ||
        (event == chromeos::disks::DiskMountManager::UNMOUNTING &&
         error_code == chromeos::MOUNT_ERROR_NONE)) {
      drive::FileSystemInterface* file_system =
          drive::util::GetFileSystemByProfile(profile_);
      if (file_system) {
        file_system->MarkCacheFileAsUnmounted(
            base::FilePath(mount_info.source_path),
            base::Bind(&OnMarkCacheFileAsUnmounted));
      }
    }
  }

  // Notify a mounting/unmounting event to observers.
  const chromeos::disks::DiskMountManager::Disk* disk =
      disk_mount_manager_->FindDiskBySourcePath(mount_info.source_path);
  VolumeInfo volume_info =
      CreateVolumeInfoFromMountPointInfo(mount_info, disk);
  switch (event) {
    case chromeos::disks::DiskMountManager::MOUNTING: {
      bool is_remounting =
          disk && mounted_disk_monitor_->DiskIsRemounting(*disk);
      FOR_EACH_OBSERVER(
          VolumeManagerObserver, observers_,
          OnVolumeMounted(error_code, volume_info, is_remounting));
      return;
    }
    case chromeos::disks::DiskMountManager::UNMOUNTING:
      FOR_EACH_OBSERVER(VolumeManagerObserver, observers_,
                        OnVolumeUnmounted(error_code, volume_info));
      return;
  }
  NOTREACHED();
}

void VolumeManager::OnFormatEvent(
    chromeos::disks::DiskMountManager::FormatEvent event,
    chromeos::FormatError error_code,
    const std::string& device_path) {
  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  DVLOG(1) << "OnDeviceEvent: " << event << ", " << error_code
           << ", " << device_path;

  switch (event) {
    case chromeos::disks::DiskMountManager::FORMAT_STARTED:
      FOR_EACH_OBSERVER(
          VolumeManagerObserver, observers_,
          OnFormatStarted(device_path,
                          error_code == chromeos::FORMAT_ERROR_NONE));
      return;
    case chromeos::disks::DiskMountManager::FORMAT_COMPLETED:
      if (error_code == chromeos::FORMAT_ERROR_NONE) {
        // If format is completed successfully, try to mount the device.
        // MountPath auto-detects filesystem format if second argument is
        // empty. The third argument (mount label) is not used in a disk mount
        // operation.
        disk_mount_manager_->MountPath(
            device_path, std::string(), std::string(),
            chromeos::MOUNT_TYPE_DEVICE);
      }

      FOR_EACH_OBSERVER(
          VolumeManagerObserver, observers_,
          OnFormatCompleted(device_path,
                            error_code == chromeos::FORMAT_ERROR_NONE));

      return;
  }
  NOTREACHED();
}

void VolumeManager::OnExternalStorageDisabledChanged() {
  // If the policy just got disabled we have to unmount every device currently
  // mounted. The opposite is fine - we can let the user re-plug her device to
  // make it available.
  if (profile_->GetPrefs()->GetBoolean(prefs::kExternalStorageDisabled)) {
    // We do not iterate on mount_points directly, because mount_points can
    // be changed by UnmountPath().
    // TODO(hidehiko): Is it necessary to unmount mounted archives, too, here?
    while (!disk_mount_manager_->mount_points().empty()) {
      std::string mount_path =
          disk_mount_manager_->mount_points().begin()->second.mount_path;
      disk_mount_manager_->UnmountPath(
          mount_path,
          chromeos::UNMOUNT_OPTIONS_NONE,
          chromeos::disks::DiskMountManager::UnmountPathCallback());
    }
  }
}

}  // namespace file_manager