// Copyright 2015 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 "components/offline_pages/offline_page_metadata_store_impl.h"

#include "base/bind.h"
#include "base/files/file_path.h"
#include "base/location.h"
#include "base/message_loop/message_loop.h"
#include "base/sequenced_task_runner.h"
#include "base/strings/utf_string_conversions.h"
#include "base/thread_task_runner_handle.h"
#include "components/leveldb_proto/proto_database.h"
#include "components/offline_pages/offline_page_item.h"
#include "components/offline_pages/proto/offline_pages.pb.h"
#include "third_party/leveldatabase/env_chromium.h"
#include "third_party/leveldatabase/src/include/leveldb/db.h"
#include "url/gurl.h"

using leveldb_proto::ProtoDatabase;

namespace offline_pages {
namespace {

typedef std::vector<OfflinePageEntry> OfflinePageEntryVector;

void OfflinePageItemToEntry(const OfflinePageItem& item,
                            offline_pages::OfflinePageEntry* item_proto) {
  DCHECK(item_proto);
  item_proto->set_url(item.url.spec());
  item_proto->set_bookmark_id(item.bookmark_id);
  item_proto->set_version(item.version);
  std::string path_string;
#if defined(OS_POSIX)
  path_string = item.file_path.value();
#elif defined(OS_WIN)
  path_string = base::WideToUTF8(item.file_path.value());
#endif
  item_proto->set_file_path(path_string);
  item_proto->set_file_size(item.file_size);
  item_proto->set_creation_time(item.creation_time.ToInternalValue());
  item_proto->set_last_access_time(item.last_access_time.ToInternalValue());
}

bool OfflinePageItemFromEntry(const offline_pages::OfflinePageEntry& item_proto,
                              OfflinePageItem* item) {
  DCHECK(item);
  if (!item_proto.has_url() || !item_proto.has_bookmark_id() ||
      !item_proto.has_version() || !item_proto.has_file_path()) {
    return false;
  }
  item->url = GURL(item_proto.url());
  item->bookmark_id = item_proto.bookmark_id();
  item->version = item_proto.version();
#if defined(OS_POSIX)
  item->file_path = base::FilePath(item_proto.file_path());
#elif defined(OS_WIN)
  item->file_path = base::FilePath(base::UTF8ToWide(item_proto.file_path()));
#endif
  if (item_proto.has_file_size()) {
    item->file_size = item_proto.file_size();
  }
  if (item_proto.has_creation_time()) {
    item->creation_time =
        base::Time::FromInternalValue(item_proto.creation_time());
  }
  if (item_proto.has_last_access_time()) {
    item->last_access_time =
        base::Time::FromInternalValue(item_proto.last_access_time());
  }
  return true;
}

void OnLoadDone(const OfflinePageMetadataStore::LoadCallback& callback,
                const base::Callback<void()>& failure_callback,
                bool success,
                scoped_ptr<OfflinePageEntryVector> entries) {
  if (!success) {
    // TODO(fgorski): Add UMA for this case.
    DVLOG(1) << "Offline pages database load failed.";
    failure_callback.Run();
    base::MessageLoop::current()->PostTask(
        FROM_HERE, base::Bind(callback, false, std::vector<OfflinePageItem>()));
    return;
  }

  std::vector<OfflinePageItem> result;
  for (OfflinePageEntryVector::iterator it = entries->begin();
       it != entries->end(); ++it) {
    OfflinePageItem item;
    if (OfflinePageItemFromEntry(*it, &item))
      result.push_back(item);
    else
      DVLOG(1) << "Failed to create offline page item from proto.";
  }

  base::MessageLoop::current()->PostTask(FROM_HERE,
                                         base::Bind(callback, true, result));
}

void OnUpdateDone(const OfflinePageMetadataStore::UpdateCallback& callback,
                  const base::Callback<void()>& failure_callback,
                  bool success) {
  if (!success) {
    // TODO(fgorski): Add UMA for this case.
    DVLOG(1) << "Offline pages database update failed.";
    failure_callback.Run();
  }

  base::MessageLoop::current()->PostTask(FROM_HERE,
                                         base::Bind(callback, success));
}

}  // namespace

OfflinePageMetadataStoreImpl::OfflinePageMetadataStoreImpl(
    scoped_ptr<ProtoDatabase<OfflinePageEntry>> database,
    const base::FilePath& database_dir)
    : database_(database.Pass()), weak_ptr_factory_(this) {
  database_->Init(database_dir,
                  base::Bind(&OfflinePageMetadataStoreImpl::OnInitDone,
                             weak_ptr_factory_.GetWeakPtr()));
}

OfflinePageMetadataStoreImpl::~OfflinePageMetadataStoreImpl() {
}

void OfflinePageMetadataStoreImpl::OnInitDone(bool success) {
  if (!success) {
    // TODO(fgorski): Add UMA for this case.
    DVLOG(1) << "Offline pages database init failed.";
    ResetDB();
    return;
  }
}

void OfflinePageMetadataStoreImpl::Load(const LoadCallback& callback) {
  if (!database_.get()) {
    // Failing fast here, because DB is not initialized, and there is nothing
    // that can be done about it.
    // Callback is invoked through message loop to avoid improper retry and
    // simplify testing.
    DVLOG(1) << "Offline pages database not available in Load.";
    base::MessageLoop::current()->PostTask(
        FROM_HERE, base::Bind(callback, false, std::vector<OfflinePageItem>()));
    return;
  }

  database_->LoadEntries(base::Bind(
      &OnLoadDone, callback, base::Bind(&OfflinePageMetadataStoreImpl::ResetDB,
                                        weak_ptr_factory_.GetWeakPtr())));
}

void OfflinePageMetadataStoreImpl::AddOfflinePage(
    const OfflinePageItem& offline_page_item,
    const UpdateCallback& callback) {
  scoped_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector> entries_to_save(
      new ProtoDatabase<OfflinePageEntry>::KeyEntryVector());
  scoped_ptr<std::vector<std::string>> keys_to_remove(
      new std::vector<std::string>());

  OfflinePageEntry offline_page_proto;
  OfflinePageItemToEntry(offline_page_item, &offline_page_proto);
  entries_to_save->push_back(
      std::make_pair(offline_page_proto.url(), offline_page_proto));

  UpdateEntries(entries_to_save.Pass(), keys_to_remove.Pass(), callback);
}

void OfflinePageMetadataStoreImpl::RemoveOfflinePage(
    const GURL& page_url,
    const UpdateCallback& callback) {
  scoped_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector> entries_to_save(
      new ProtoDatabase<OfflinePageEntry>::KeyEntryVector());
  scoped_ptr<std::vector<std::string>> keys_to_remove(
      new std::vector<std::string>());

  keys_to_remove->push_back(page_url.spec());

  UpdateEntries(entries_to_save.Pass(), keys_to_remove.Pass(), callback);
}

void OfflinePageMetadataStoreImpl::UpdateEntries(
    scoped_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector> entries_to_save,
    scoped_ptr<std::vector<std::string>> keys_to_remove,
    const UpdateCallback& callback) {
  if (!database_.get()) {
    // Failing fast here, because DB is not initialized, and there is nothing
    // that can be done about it.
    // Callback is invoked through message loop to avoid improper retry and
    // simplify testing.
    DVLOG(1) << "Offline pages database not available in UpdateEntries.";
    base::MessageLoop::current()->PostTask(FROM_HERE,
                                           base::Bind(callback, false));
    return;
  }

  database_->UpdateEntries(
      entries_to_save.Pass(), keys_to_remove.Pass(),
      base::Bind(&OnUpdateDone, callback,
                 base::Bind(&OfflinePageMetadataStoreImpl::ResetDB,
                            weak_ptr_factory_.GetWeakPtr())));
}

void OfflinePageMetadataStoreImpl::ResetDB() {
  database_.reset();
  weak_ptr_factory_.InvalidateWeakPtrs();
}

}  // namespace offline_pages