// Copyright (c) 2015 The Chromium Embedded Framework Authors.
// Portions copyright (c) 2006-2009 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 "libcef/browser/net/url_request_manager.h"

#include "include/cef_browser.h"
#include "include/cef_scheme.h"
#include "libcef/browser/browser_context.h"
#include "libcef/browser/browser_host_impl.h"
#include "libcef/browser/net/resource_request_job.h"
#include "libcef/browser/net/scheme_handler.h"
#include "libcef/browser/thread_util.h"
#include "libcef/common/net/scheme_registration.h"
#include "libcef/common/request_impl.h"

#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/strings/string_util.h"
#include "net/url_request/url_request.h"
#include "net/url_request/url_request_context.h"
#include "net/url_request/url_request_filter.h"
#include "net/url_request/url_request_http_job.h"
#include "net/url_request/url_request_job.h"
#include "net/url_request/url_request_job_factory_impl.h"
#include "url/third_party/mozilla/url_parse.h"
#include "url/url_util.h"

using net::URLRequestStatus;

namespace {

bool IsStandardScheme(const std::string& scheme) {
  url::Component scheme_comp(0, scheme.length());
  return url::IsStandard(scheme.c_str(), scheme_comp);
}

// Copied from net/url_request/url_request_job_manager.cc.
struct SchemeToFactory {
  const char* scheme;
  net::URLRequest::ProtocolFactory* factory;
};
static const SchemeToFactory kBuiltinFactories[] = {
    {"http", net::URLRequestHttpJob::Factory},
    {"https", net::URLRequestHttpJob::Factory},
};

bool IsBuiltinScheme(const std::string& scheme) {
  for (size_t i = 0; i < arraysize(kBuiltinFactories); ++i)
    if (base::LowerCaseEqualsASCII(scheme, kBuiltinFactories[i].scheme))
      return true;
  return false;
}

net::URLRequestJob* GetBuiltinSchemeRequestJob(
    net::URLRequest* request,
    net::NetworkDelegate* network_delegate,
    const std::string& scheme) {
  // See if the request should be handled by a built-in protocol factory.
  for (size_t i = 0; i < arraysize(kBuiltinFactories); ++i) {
    if (scheme == kBuiltinFactories[i].scheme) {
      net::URLRequestJob* job =
          (kBuiltinFactories[i].factory)(request, network_delegate, scheme);
      DCHECK(job);  // The built-in factories are not expected to fail!
      return job;
    }
  }

  return NULL;
}

std::string ToLower(const std::string& str) {
  std::string str_lower = str;
  std::transform(str_lower.begin(), str_lower.end(), str_lower.begin(),
                 towlower);
  return str;
}

}  // namespace

// Class used for creating URLRequestJob instances. The lifespan of this object
// is managed by URLRequestJobFactory.
class CefProtocolHandler : public net::URLRequestJobFactory::ProtocolHandler {
 public:
  CefProtocolHandler(CefURLRequestManager* request_manager,
                     const std::string& scheme)
      : request_manager_(request_manager), scheme_(scheme) {}

  // From net::URLRequestJobFactory::ProtocolHandler
  net::URLRequestJob* MaybeCreateJob(
      net::URLRequest* request,
      net::NetworkDelegate* network_delegate) const override {
    CEF_REQUIRE_IOT();
    return request_manager_->GetRequestJob(request, network_delegate, scheme_);
  }

 private:
  CefURLRequestManager* request_manager_;
  std::string scheme_;
};

CefURLRequestManager::CefURLRequestManager(
    net::URLRequestJobFactoryImpl* job_factory)
    : job_factory_(job_factory) {
  CEF_REQUIRE_IOT();
  DCHECK(job_factory_);
}

CefURLRequestManager::~CefURLRequestManager() {
  CEF_REQUIRE_IOT();
}

bool CefURLRequestManager::AddFactory(
    const std::string& scheme,
    const std::string& domain,
    CefRefPtr<CefSchemeHandlerFactory> factory) {
  if (!factory.get()) {
    RemoveFactory(scheme, domain);
    return true;
  }

  CEF_REQUIRE_IOT();

  std::string scheme_lower = ToLower(scheme);
  std::string domain_lower = ToLower(domain);

  // Hostname is only supported for standard schemes.
  if (!IsStandardScheme(scheme_lower))
    domain_lower.clear();

  SetProtocolHandlerIfNecessary(scheme_lower, true);

  handler_map_[make_pair(scheme_lower, domain_lower)] = factory;

  return true;
}

void CefURLRequestManager::RemoveFactory(const std::string& scheme,
                                         const std::string& domain) {
  CEF_REQUIRE_IOT();

  std::string scheme_lower = ToLower(scheme);
  std::string domain_lower = ToLower(domain);

  // Hostname is only supported for standard schemes.
  if (!IsStandardScheme(scheme_lower))
    domain_lower.clear();

  HandlerMap::iterator iter =
      handler_map_.find(make_pair(scheme_lower, domain_lower));
  if (iter != handler_map_.end()) {
    handler_map_.erase(iter);

    SetProtocolHandlerIfNecessary(scheme_lower, false);
  }
}

// Clear all the existing URL handlers and unregister the ProtocolFactory.
void CefURLRequestManager::ClearFactories() {
  CEF_REQUIRE_IOT();

  // Create a unique set of scheme names.
  std::set<std::string> schemes;
  for (HandlerMap::const_iterator i = handler_map_.begin();
       i != handler_map_.end(); ++i) {
    schemes.insert(i->first.first);
  }

  for (std::set<std::string>::const_iterator scheme = schemes.begin();
       scheme != schemes.end(); ++scheme) {
    const std::string& scheme_name = *scheme;
    if (!scheme::IsInternalProtectedScheme(scheme_name)) {
      bool set_protocol = job_factory_->SetProtocolHandler(scheme_name, NULL);
      DCHECK(set_protocol);
    }
  }

  handler_map_.clear();

  // Re-register internal scheme handlers that can be overridden.
  scheme::RegisterInternalHandlers(this);
}

// Helper for chaining ProtocolHandler implementations.
net::URLRequestJob* CefURLRequestManager::GetRequestJob(
    net::URLRequest* request,
    net::NetworkDelegate* network_delegate) {
  CEF_REQUIRE_IOT();
  return GetRequestJob(request, network_delegate, request->url().scheme());
}

void CefURLRequestManager::SetProtocolHandlerIfNecessary(
    const std::string& scheme,
    bool add) {
  // Don't modify a protocol handler for internal protected schemes or if the
  // protocol handler is still needed by other registered factories.
  if (scheme::IsInternalProtectedScheme(scheme) || HasFactory(scheme))
    return;

  bool set_protocol = job_factory_->SetProtocolHandler(
      scheme,
      base::WrapUnique(add ? new CefProtocolHandler(this, scheme) : NULL));
  DCHECK(set_protocol);
}

bool CefURLRequestManager::HasFactory(const std::string& scheme) {
  if (handler_map_.empty())
    return false;

  for (HandlerMap::const_iterator i = handler_map_.begin();
       i != handler_map_.end(); ++i) {
    if (scheme == i->first.first)
      return true;
  }

  return false;
}

CefRefPtr<CefSchemeHandlerFactory> CefURLRequestManager::GetHandlerFactory(
    net::URLRequest* request,
    const std::string& scheme) {
  CefRefPtr<CefSchemeHandlerFactory> factory;

  if (request->url().is_valid() && IsStandardScheme(scheme)) {
    // Check for a match with a domain first.
    const std::string& domain = request->url().host();

    HandlerMap::iterator i = handler_map_.find(make_pair(scheme, domain));
    if (i != handler_map_.end())
      factory = i->second;
  }

  if (!factory.get()) {
    // Check for a match with no specified domain.
    HandlerMap::iterator i =
        handler_map_.find(make_pair(scheme, std::string()));
    if (i != handler_map_.end())
      factory = i->second;
  }

  return factory;
}

net::URLRequestJob* CefURLRequestManager::GetRequestJob(
    net::URLRequest* request,
    net::NetworkDelegate* network_delegate,
    const std::string& scheme) {
  net::URLRequestJob* job = NULL;
  CefRefPtr<CefSchemeHandlerFactory> factory =
      GetHandlerFactory(request, scheme);
  if (factory.get()) {
    CefRefPtr<CefBrowserHostImpl> browser =
        CefBrowserHostImpl::GetBrowserForRequest(request);
    CefRefPtr<CefFrame> frame;
    if (browser.get())
      frame = browser->GetFrameForRequest(request);

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

    // Call the handler factory to create the handler for the request.
    CefRefPtr<CefResourceHandler> handler =
        factory->Create(browser.get(), frame, scheme, requestPtr.get());
    if (handler.get())
      job = new CefResourceRequestJob(request, network_delegate, handler);
  }

  if (!job && IsBuiltinScheme(scheme)) {
    // Give the built-in scheme handler a chance to handle the request.
    job = GetBuiltinSchemeRequestJob(request, network_delegate, scheme);
  }

#if DCHECK_IS_ON()
  if (job)
    DLOG(INFO) << "CefURLRequestManager hit for " << request->url().spec();
#endif

  return job;
}
