// Copyright (c) 2012 The Chromium Embedded Framework 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 "libcef/browser/net/network_delegate.h"

#include <string>
#include <utility>

#include "include/cef_urlrequest.h"
#include "libcef/browser/browser_host_impl.h"
#include "libcef/browser/net/response_filter_wrapper.h"
#include "libcef/browser/net/url_request_user_data.h"
#include "libcef/browser/thread_util.h"
#include "libcef/common/request_impl.h"
#include "libcef/common/response_impl.h"

#include "base/command_line.h"
#include "base/metrics/field_trial.h"
#include "base/strings/string_util.h"
#include "chrome/browser/net/safe_search_util.h"
#include "components/prefs/pref_member.h"
#include "components/prefs/pref_service.h"
#include "content/public/common/content_switches.h"
#include "net/base/net_errors.h"
#include "net/filter/filter.h"
#include "net/http/http_util.h"
#include "net/url_request/url_request.h"

namespace {

// Buffer size allocated when filtering data.
// Should match the value in net/filter/filter.cc.
const int kFilterBufSize = 32 * 1024;

class CefBeforeResourceLoadCallbackImpl : public CefRequestCallback {
 public:
  typedef net::CompletionCallback CallbackType;

  CefBeforeResourceLoadCallbackImpl(
      CefRefPtr<CefRequestImpl> cef_request,
      GURL* new_url,
      net::URLRequest* url_request,
      bool force_google_safesearch,
      const CallbackType& callback)
      : cef_request_(cef_request),
        new_url_(new_url),
        url_request_(url_request),
        force_google_safesearch_(force_google_safesearch),
        callback_(callback) {
    DCHECK(new_url);
    DCHECK(url_request_);

    // Add an association between the URLRequest and this object.
    url_request_->SetUserData(UserDataKey(), new Disconnector(this));
  }

  ~CefBeforeResourceLoadCallbackImpl() {
    if (!callback_.is_null()) {
      // The callback is still pending. Cancel it now.
      if (CEF_CURRENTLY_ON_IOT()) {
        RunNow(cef_request_, new_url_, url_request_, callback_,
               force_google_safesearch_, false);
      } else {
        CEF_POST_TASK(CEF_IOT,
            base::Bind(&CefBeforeResourceLoadCallbackImpl::RunNow,
                       cef_request_, new_url_, url_request_, callback_,
                       force_google_safesearch_, false));
      }
    }
  }

  void Continue(bool allow) override {
    // Always continue asynchronously.
    CEF_POST_TASK(CEF_IOT,
        base::Bind(&CefBeforeResourceLoadCallbackImpl::ContinueNow,
                   this, allow));
  }

  void Cancel() override {
    Continue(false);
  }

  void ContinueNow(bool allow) {
    CEF_REQUIRE_IOT();
    if (!callback_.is_null()) {
      RunNow(cef_request_, new_url_, url_request_, callback_,
             force_google_safesearch_, allow);
      Disconnect();
    }
  }

  void Disconnect() {
    CEF_REQUIRE_IOT();
    cef_request_ = nullptr;
    new_url_ = nullptr;
    url_request_ = nullptr;
    callback_.Reset();
  }

 private:
  // Used to disconnect the callback when the associated URLRequest is
  // destroyed.
  class Disconnector : public base::SupportsUserData::Data {
   public:
    explicit Disconnector(CefBeforeResourceLoadCallbackImpl* callback)
        : callback_(callback) {
    }
    ~Disconnector() override {
      if (callback_)
        callback_->Disconnect();
    }

    void Disconnect() {
      callback_ = NULL;
    }

   private:
    CefBeforeResourceLoadCallbackImpl* callback_;
  };

  static void RunNow(CefRefPtr<CefRequestImpl> cef_request,
                     GURL* new_url,
                     net::URLRequest* request,
                     const CallbackType& callback,
                     bool force_google_safesearch,
                     bool allow) {
    CEF_REQUIRE_IOT();

    if (allow) {
      // Update the URLRequest with only the values that have been changed by
      // the client.
      cef_request->Get(request, true);

      if (!!(cef_request->GetChanges() & CefRequestImpl::kChangedUrl)) {
        // If the URL was changed then redirect the request.
        GURL url = GURL(cef_request->GetURL().ToString());
        DCHECK_NE(url, request->url());
        new_url->Swap(&url);
      }
    }

    // Remove the association between the URLRequest and this object.
    Disconnector* disconnector =
        static_cast<Disconnector*>(request->GetUserData(UserDataKey()));
    DCHECK(disconnector);
    disconnector->Disconnect();
    request->RemoveUserData(UserDataKey());

    // Only execute the callback if the request has not been canceled.
    if (request->status().status() != net::URLRequestStatus::CANCELED) {
      if (force_google_safesearch && allow && new_url->is_empty())
        safe_search_util::ForceGoogleSafeSearch(request, new_url);

      callback.Run(allow ? net::OK : net::ERR_ABORTED);
    }
  }

  static inline void* UserDataKey() {
    return &kLocatorKey;
  }

  CefRefPtr<CefRequestImpl> cef_request_;
  const GURL old_url_;
  GURL* new_url_;
  net::URLRequest* url_request_;
  bool force_google_safesearch_;
  CallbackType callback_;

  // The user data key.
  static int kLocatorKey;

  IMPLEMENT_REFCOUNTING(CefBeforeResourceLoadCallbackImpl);
  DISALLOW_COPY_AND_ASSIGN(CefBeforeResourceLoadCallbackImpl);
};

int CefBeforeResourceLoadCallbackImpl::kLocatorKey = 0;

class CefAuthCallbackImpl : public CefAuthCallback {
 public:
  CefAuthCallbackImpl(const net::NetworkDelegate::AuthCallback& callback,
                      net::AuthCredentials* credentials)
      : callback_(callback),
        credentials_(credentials) {
  }
  ~CefAuthCallbackImpl() override {
    if (!callback_.is_null()) {
      // The auth callback is still pending. Cancel it now.
      if (CEF_CURRENTLY_ON_IOT()) {
        CancelNow(callback_);
      } else {
        CEF_POST_TASK(CEF_IOT,
            base::Bind(&CefAuthCallbackImpl::CancelNow, callback_));
      }
    }
  }

  void Continue(const CefString& username,
                const CefString& password) override {
    if (CEF_CURRENTLY_ON_IOT()) {
      if (!callback_.is_null()) {
        credentials_->Set(username, password);
        callback_.Run(net::NetworkDelegate::AUTH_REQUIRED_RESPONSE_SET_AUTH);
        callback_.Reset();
      }
    } else {
      CEF_POST_TASK(CEF_IOT,
          base::Bind(&CefAuthCallbackImpl::Continue, this, username, password));
    }
  }

  void Cancel() override {
    if (CEF_CURRENTLY_ON_IOT()) {
      if (!callback_.is_null()) {
        CancelNow(callback_);
        callback_.Reset();
      }
    } else {
      CEF_POST_TASK(CEF_IOT, base::Bind(&CefAuthCallbackImpl::Cancel, this));
    }
  }

  void Disconnect() {
    callback_.Reset();
  }

 private:
  static void CancelNow(const net::NetworkDelegate::AuthCallback& callback) {
    CEF_REQUIRE_IOT();
    callback.Run(net::NetworkDelegate::AUTH_REQUIRED_RESPONSE_NO_ACTION);
  }

  net::NetworkDelegate::AuthCallback callback_;
  net::AuthCredentials* credentials_;

  IMPLEMENT_REFCOUNTING(CefAuthCallbackImpl);
};

}  // namespace

CefNetworkDelegate::CefNetworkDelegate()
  : force_google_safesearch_(nullptr) {
}

CefNetworkDelegate::~CefNetworkDelegate() {
}

// static
bool CefNetworkDelegate::AreExperimentalCookieFeaturesEnabled() {
  static bool initialized = false;
  static bool enabled = false;
  if (!initialized) {
    enabled = base::CommandLine::ForCurrentProcess()->
        HasSwitch(switches::kEnableExperimentalWebPlatformFeatures);
    initialized = true;
  }
  return enabled;
}

// static
bool CefNetworkDelegate::AreStrictSecureCookiesEnabled() {
  const std::string enforce_strict_secure_group =
      base::FieldTrialList::FindFullName("StrictSecureCookies");
  return AreExperimentalCookieFeaturesEnabled() ||
         base::StartsWith(enforce_strict_secure_group, "Enabled",
                          base::CompareCase::INSENSITIVE_ASCII);
}

int CefNetworkDelegate::OnBeforeURLRequest(
    net::URLRequest* request,
    const net::CompletionCallback& callback,
    GURL* new_url) {
  const bool force_google_safesearch =
      (force_google_safesearch_ && force_google_safesearch_->GetValue());

  CefRefPtr<CefBrowserHostImpl> browser =
      CefBrowserHostImpl::GetBrowserForRequest(request);
  if (browser.get()) {
    const CefBrowserSettings& browser_settings = browser->settings();
    if (browser_settings.accept_language_list.length > 0) {
      const std::string& accept_language =
          net::HttpUtil::GenerateAcceptLanguageHeader(
              CefString(&browser_settings.accept_language_list));
      request->SetExtraRequestHeaderByName(
          net::HttpRequestHeaders::kAcceptLanguage, accept_language, false);
    }
    CefRefPtr<CefClient> client = browser->GetClient();
    if (client.get()) {
      CefRefPtr<CefRequestHandler> handler = client->GetRequestHandler();
      if (handler.get()) {
        CefRefPtr<CefFrame> frame = browser->GetFrameForRequest(request);

        // Populate the request data.
        CefRefPtr<CefRequestImpl> requestPtr(new CefRequestImpl());
        requestPtr->Set(request);
        requestPtr->SetTrackChanges(true);

        CefRefPtr<CefBeforeResourceLoadCallbackImpl> callbackImpl(
            new CefBeforeResourceLoadCallbackImpl(requestPtr, new_url, request,
                                                  force_google_safesearch,
                                                  callback));

        // Give the client an opportunity to evaluate the request.
        cef_return_value_t retval = handler->OnBeforeResourceLoad(
            browser.get(), frame, requestPtr.get(), callbackImpl.get());
        if (retval == RV_CANCEL) {
          // Cancel the request.
          callbackImpl->Continue(false);
        } else if (retval == RV_CONTINUE) {
          // Continue the request.
          callbackImpl->Continue(true);
        }

        // Continue or cancel the request asynchronously.
        return net::ERR_IO_PENDING;
      }
    }
  }

  if (force_google_safesearch && new_url->is_empty())
    safe_search_util::ForceGoogleSafeSearch(request, new_url);

  // Continue the request immediately.
  return net::OK;
}

void CefNetworkDelegate::OnCompleted(net::URLRequest* request, bool started) {
  if (!started)
    return;

  CefRefPtr<CefBrowserHostImpl> browser =
      CefBrowserHostImpl::GetBrowserForRequest(request);
  if (browser.get()) {
    CefRefPtr<CefClient> client = browser->GetClient();
    if (client.get()) {
      CefRefPtr<CefRequestHandler> handler = client->GetRequestHandler();
      if (handler.get()) {
        CefRefPtr<CefFrame> frame = browser->GetFrameForRequest(request);

        CefRefPtr<CefRequestImpl> cefRequest = new CefRequestImpl();
        cefRequest->Set(request);
        cefRequest->SetReadOnly(true);

        CefRefPtr<CefResponseImpl> cefResponse = new CefResponseImpl();
        cefResponse->Set(request);
        cefResponse->SetReadOnly(true);

        cef_urlrequest_status_t status = UR_UNKNOWN;
        switch (request->status().status()) {
          case net::URLRequestStatus::SUCCESS:
            status = UR_SUCCESS;
            break;
          case net::URLRequestStatus::CANCELED:
            status = UR_CANCELED;
            break;
          case net::URLRequestStatus::FAILED:
            status = UR_FAILED;
            break;
          default:
            NOTREACHED();
            break;
        }

        const int64 received_content_length =
            request->received_response_content_length();
        handler->OnResourceLoadComplete(browser.get(),
                                        frame,
                                        cefRequest.get(),
                                        cefResponse.get(),
                                        status,
                                        received_content_length);
      }
    }
  }
}

net::NetworkDelegate::AuthRequiredResponse CefNetworkDelegate::OnAuthRequired(
    net::URLRequest* request,
    const net::AuthChallengeInfo& auth_info,
    const AuthCallback& callback,
    net::AuthCredentials* credentials) {
  CefRefPtr<CefBrowserHostImpl> browser =
      CefBrowserHostImpl::GetBrowserForRequest(request);
  if (browser.get()) {
    CefRefPtr<CefClient> client = browser->GetClient();
    if (client.get()) {
      CefRefPtr<CefRequestHandler> handler = client->GetRequestHandler();
      if (handler.get()) {
        CefRefPtr<CefFrame> frame = browser->GetFrameForRequest(request);

        CefRefPtr<CefAuthCallbackImpl> callbackPtr(
            new CefAuthCallbackImpl(callback, credentials));
        if (handler->GetAuthCredentials(browser.get(),
                                        frame,
                                        auth_info.is_proxy,
                                        auth_info.challenger.host(),
                                        auth_info.challenger.port(),
                                        auth_info.realm,
                                        auth_info.scheme,
                                        callbackPtr.get())) {
          return AUTH_REQUIRED_RESPONSE_IO_PENDING;
        } else {
          callbackPtr->Disconnect();
        }
      }
    }
  }

  CefURLRequestUserData* user_data =
      (CefURLRequestUserData*)request->GetUserData(
          CefURLRequestUserData::kUserDataKey);
  if (user_data) {
    CefRefPtr<CefURLRequestClient> client = user_data->GetClient();
    if (client.get()) {
      CefRefPtr<CefAuthCallbackImpl> callbackPtr(
          new CefAuthCallbackImpl(callback, credentials));
      if (client->GetAuthCredentials(auth_info.is_proxy,
                                     auth_info.challenger.host(),
                                     auth_info.challenger.port(),
                                     auth_info.realm,
                                     auth_info.scheme,
                                     callbackPtr.get())) {
        return AUTH_REQUIRED_RESPONSE_IO_PENDING;
      } else {
        callbackPtr->Disconnect();
      }
    }
  }

  return AUTH_REQUIRED_RESPONSE_NO_ACTION;
}

bool CefNetworkDelegate::OnCanAccessFile(const net::URLRequest& request,
                                         const base::FilePath& path) const {
  return true;
}

bool CefNetworkDelegate::OnAreExperimentalCookieFeaturesEnabled() const {
  return AreExperimentalCookieFeaturesEnabled();
}

bool CefNetworkDelegate::OnAreStrictSecureCookiesEnabled() const {
  return AreStrictSecureCookiesEnabled();
}

net::Filter* CefNetworkDelegate::SetupFilter(net::URLRequest* request,
                                             net::Filter* filter_list) {
  CefRefPtr<CefResponseFilter> cef_filter;

  CefRefPtr<CefBrowserHostImpl> browser =
      CefBrowserHostImpl::GetBrowserForRequest(request);
  if (browser.get()) {
    CefRefPtr<CefClient> client = browser->GetClient();
    if (client.get()) {
      CefRefPtr<CefRequestHandler> handler = client->GetRequestHandler();
      if (handler.get()) {
        CefRefPtr<CefFrame> frame = browser->GetFrameForRequest(request);

        CefRefPtr<CefRequestImpl> cefRequest = new CefRequestImpl();
        cefRequest->Set(request);
        cefRequest->SetReadOnly(true);

        CefRefPtr<CefResponseImpl> cefResponse = new CefResponseImpl();
        cefResponse->Set(request);
        cefResponse->SetReadOnly(true);

        cef_filter = handler->GetResourceResponseFilter(browser.get(), frame,
                                                        cefRequest.get(),
                                                        cefResponse.get());
      }
    }
  }

  if (cef_filter.get() && cef_filter->InitFilter()) {
    std::unique_ptr<CefResponseFilterWrapper> wrapper(
        new CefResponseFilterWrapper(cef_filter, filter_list != nullptr));
    wrapper->InitBuffer(kFilterBufSize);

    if (filter_list) {
      // Install the wrapper at the end of the filter list.
      net::Filter* last_filter = filter_list;
      do {
        if (!last_filter->next_filter_.get()) {
          last_filter->next_filter_ = std::move(wrapper);
          break;
        }
        last_filter = last_filter->next_filter_.get();
      } while (last_filter);
    } else {
      // Only the wrapper exists.
      filter_list = wrapper.release();
    }
  }

  return filter_list;
}