// 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/extensions/api/system_storage/storage_info_provider.h"

#include "base/stl_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/sys_info.h"
#include "base/threading/sequenced_worker_pool.h"
#include "chrome/browser/storage_monitor/storage_monitor.h"
#include "content/public/browser/browser_thread.h"

namespace extensions {

using content::BrowserThread;
using chrome::StorageMonitor;
using api::system_storage::StorageUnitInfo;
using api::system_storage::STORAGE_UNIT_TYPE_FIXED;
using api::system_storage::STORAGE_UNIT_TYPE_REMOVABLE;

namespace systeminfo {

void BuildStorageUnitInfo(const chrome::StorageInfo& info,
                          StorageUnitInfo* unit) {
  unit->id = StorageMonitor::GetInstance()->GetTransientIdForDeviceId(
                 info.device_id());
  unit->name = UTF16ToUTF8(info.name());
  // TODO(hmin): Might need to take MTP device into consideration.
  unit->type = chrome::StorageInfo::IsRemovableDevice(info.device_id()) ?
      STORAGE_UNIT_TYPE_REMOVABLE : STORAGE_UNIT_TYPE_FIXED;
  unit->capacity = static_cast<double>(info.total_size_in_bytes());
}

}  // namespace systeminfo

// Static member intialization.
base::LazyInstance<scoped_refptr<StorageInfoProvider> >
    StorageInfoProvider::provider_ = LAZY_INSTANCE_INITIALIZER;

StorageInfoProvider::StorageInfoProvider() {
}

StorageInfoProvider::~StorageInfoProvider() {
}

const StorageUnitInfoList& StorageInfoProvider::storage_unit_info_list() const {
  return info_;
}

void StorageInfoProvider::InitializeForTesting(
    scoped_refptr<StorageInfoProvider> provider) {
  DCHECK(provider.get() != NULL);
  provider_.Get() = provider;
}

void StorageInfoProvider::PrepareQueryOnUIThread() {
  // Get all available storage devices before invoking |QueryInfo()|.
  GetAllStoragesIntoInfoList();
}

void StorageInfoProvider::InitializeProvider(
    const base::Closure& do_query_info_callback) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  // Register the |do_query_info_callback| callback to StorageMonitor.
  // See the comments of StorageMonitor::EnsureInitialized about when the
  // callback gets run.
  StorageMonitor::GetInstance()->EnsureInitialized(do_query_info_callback);
}

bool StorageInfoProvider::QueryInfo() {
  DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
  // No info to query since we get all available storage devices' info in
  // |PrepareQueryOnUIThread()|.
  return true;
}

void StorageInfoProvider::GetAllStoragesIntoInfoList() {
  info_.clear();
  std::vector<chrome::StorageInfo> storage_list =
      StorageMonitor::GetInstance()->GetAllAvailableStorages();

  std::vector<chrome::StorageInfo>::const_iterator it = storage_list.begin();
  for (; it != storage_list.end(); ++it) {
    linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
    systeminfo::BuildStorageUnitInfo(*it, unit.get());
    info_.push_back(unit);
  }
}

// static
StorageInfoProvider* StorageInfoProvider::Get() {
  if (provider_.Get().get() == NULL)
    provider_.Get() = new StorageInfoProvider();
  return provider_.Get();
}

}  // namespace extensions