// 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/blacklist_state_fetcher.h"

#include "base/strings/stringprintf.h"
#include "base/threading/thread_task_runner_handle.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/safe_browsing/safe_browsing_service.h"
#include "chrome/common/safe_browsing/crx_info.pb.h"
#include "google_apis/google_api_keys.h"
#include "net/base/escape.h"
#include "net/traffic_annotation/network_traffic_annotation.h"
#include "net/url_request/url_request_context.h"
#include "net/url_request/url_request_context_getter.h"
#include "net/url_request/url_request_status.h"
#include "url/gurl.h"

using content::BrowserThread;

namespace extensions {

BlacklistStateFetcher::BlacklistStateFetcher()
    : url_fetcher_id_(0),
      weak_ptr_factory_(this) {}

BlacklistStateFetcher::~BlacklistStateFetcher() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
}

void BlacklistStateFetcher::Request(const std::string& id,
                                    const RequestCallback& callback) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  if (!safe_browsing_config_) {
    if (g_browser_process && g_browser_process->safe_browsing_service()) {
      SetSafeBrowsingConfig(
          g_browser_process->safe_browsing_service()->GetProtocolConfig());
    } else {
      base::ThreadTaskRunnerHandle::Get()->PostTask(
          FROM_HERE, base::BindOnce(callback, BLACKLISTED_UNKNOWN));
      return;
    }
  }

  bool request_already_sent = base::ContainsKey(callbacks_, id);
  callbacks_.insert(std::make_pair(id, callback));
  if (request_already_sent)
    return;

  if (!url_request_context_getter_ && g_browser_process &&
      g_browser_process->safe_browsing_service()) {
    url_request_context_getter_ =
        g_browser_process->safe_browsing_service()->url_request_context();
  }

  SendRequest(id);
}

void BlacklistStateFetcher::SendRequest(const std::string& id) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  ClientCRXListInfoRequest request;
  request.set_id(id);
  std::string request_str;
  request.SerializeToString(&request_str);

  GURL request_url = RequestUrl();
  net::NetworkTrafficAnnotationTag traffic_annotation =
      net::DefineNetworkTrafficAnnotation("extension_blacklist", R"(
        semantics {
          sender: "Extension Blacklist"
          description:
            "Chromium protects the users from malicious extensions by checking "
            "extensions that are being installed or have been installed "
            "against a list of known malwares. Chromium sends the identifiers "
            "of extensions to Google and Google responds with whether it "
            "believes each extension is malware or not. Only extensions that "
            "match the safe browsing blacklist can trigger this request."
          trigger:
            "When extensions are being installed and at startup when existing "
            "extensions are scanned."
          data: "The identifier of the installed extension."
          destination: GOOGLE_OWNED_SERVICE
        }
        policy {
          cookies_allowed: true
          cookies_store: "Safe Browsing cookies store"
          setting:
            "Users can enable or disable this feature by toggling 'Protect you "
            "and your device from dangerous sites' in Chromium settings under "
            "Privacy. This feature is enabled by default."
          chrome_policy {
            SafeBrowsingEnabled {
              policy_options {mode: MANDATORY}
              SafeBrowsingEnabled: false
            }
          }
        })");
  std::unique_ptr<net::URLFetcher> fetcher_ptr =
      net::URLFetcher::Create(url_fetcher_id_++, request_url,
                              net::URLFetcher::POST, this, traffic_annotation);
  net::URLFetcher* fetcher = fetcher_ptr.get();
  requests_[fetcher] = {std::move(fetcher_ptr), id};
  fetcher->SetAutomaticallyRetryOn5xx(false);  // Don't retry on error.
  fetcher->SetRequestContext(url_request_context_getter_.get());
  fetcher->SetUploadData("application/octet-stream", request_str);
  fetcher->Start();
}

void BlacklistStateFetcher::SetSafeBrowsingConfig(
    const safe_browsing::SafeBrowsingProtocolConfig& config) {
  safe_browsing_config_.reset(
      new safe_browsing::SafeBrowsingProtocolConfig(config));
}

void BlacklistStateFetcher::SetURLRequestContextForTest(
      net::URLRequestContextGetter* request_context) {
  url_request_context_getter_ = request_context;
}

GURL BlacklistStateFetcher::RequestUrl() const {
  std::string url = base::StringPrintf(
      "%s/%s?client=%s&appver=%s&pver=2.2",
      safe_browsing_config_->url_prefix.c_str(),
      "clientreport/crx-list-info",
      safe_browsing_config_->client_name.c_str(),
      safe_browsing_config_->version.c_str());
  std::string api_key = google_apis::GetAPIKey();
  if (!api_key.empty()) {
    base::StringAppendF(&url, "&key=%s",
                        net::EscapeQueryParamValue(api_key, true).c_str());
  }
  return GURL(url);
}

void BlacklistStateFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  auto it = requests_.find(source);
  if (it == requests_.end()) {
    NOTREACHED();
    return;
  }

  std::unique_ptr<net::URLFetcher> fetcher = std::move(it->second.first);
  std::string id = it->second.second;
  requests_.erase(it);

  BlacklistState state;

  if (source->GetStatus().is_success() && source->GetResponseCode() == 200) {
    std::string data;
    source->GetResponseAsString(&data);
    ClientCRXListInfoResponse response;
    if (response.ParseFromString(data)) {
      state = static_cast<BlacklistState>(response.verdict());
    } else {
      state = BLACKLISTED_UNKNOWN;
    }
  } else {
    if (source->GetStatus().status() == net::URLRequestStatus::FAILED) {
      VLOG(1) << "Blacklist request for: " << id
              << " failed with error: " << source->GetStatus().error();
    } else {
      VLOG(1) << "Blacklist request for: " << id
              << " failed with error: " << source->GetResponseCode();
    }

    state = BLACKLISTED_UNKNOWN;
  }

  std::pair<CallbackMultiMap::iterator, CallbackMultiMap::iterator> range =
      callbacks_.equal_range(id);
  for (CallbackMultiMap::const_iterator callback_it = range.first;
       callback_it != range.second;
       ++callback_it) {
    callback_it->second.Run(state);
  }

  callbacks_.erase(range.first, range.second);
}

}  // namespace extensions