// 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 "mojo/services/network/host_resolver_impl.h"

#include "mojo/services/network/net_adapters.h"
#include "mojo/services/network/net_address_type_converters.h"
#include "net/base/address_family.h"
#include "net/base/address_list.h"
#include "net/base/host_port_pair.h"
#include "net/base/net_errors.h"
#include "net/dns/host_resolver.h"
#include "third_party/mojo/src/mojo/public/cpp/bindings/array.h"

namespace mojo {
namespace {

class HostResolverImplJob {
 public:
  // After creating a HostResolverImplJob, |Start| must be called.
  HostResolverImplJob(net::HostResolver::RequestInfo request_info,
                      const HostResolver::GetHostAddressesCallback& callback)
      : callback_(callback),
        request_info_(request_info) {
  }

  // You are required to call |Start|. The object will automatically be deleted
  // when OnResolveDone is called.
  void Start(net::HostResolver* resolver) {
    DCHECK(resolver);
    net::BoundNetLog net_log;
    int result = resolver->Resolve(
        request_info_,
        net::DEFAULT_PRIORITY,
        &addresses_,
        base::Bind(&HostResolverImplJob::OnResolveDone, base::Unretained(this)),
        &handle_,
        net_log);
    if (result == net::ERR_IO_PENDING) {
      return;
    }
    // Synchronous result.
    OnResolveDone(result);
  }

 private:
  ~HostResolverImplJob() {
    DCHECK(thread_checker_.CalledOnValidThread());
  }

  void OnResolveDone(int result) {
    DCHECK(thread_checker_.CalledOnValidThread());
    Array<NetAddressPtr> net_addresses;
    if (result == net::OK) {
      for (size_t i = 0; i < addresses_.size(); i++) {
        net_addresses.push_back(NetAddress::From(addresses_[i]));
      }
    }
    callback_.Run(MakeNetworkError(result), net_addresses.Pass());
    delete this;
  }

  HostResolver::GetHostAddressesCallback callback_;

  net::HostResolver::RequestInfo request_info_;
  net::HostResolver::RequestHandle handle_;
  net::AddressList addresses_;
  base::ThreadChecker thread_checker_;

  DISALLOW_COPY_AND_ASSIGN(HostResolverImplJob);
};

}  // namespace

HostResolverImpl::HostResolverImpl(InterfaceRequest<HostResolver> request)
    : binding_(this, request.Pass()),
      resolver_(net::HostResolver::CreateDefaultResolver(nullptr).Pass()) {
  DCHECK(resolver_);
}

HostResolverImpl::~HostResolverImpl() {
  DCHECK(thread_checker_.CalledOnValidThread());
}

static net::AddressFamily ConvertFamily(NetAddressFamily family) {
  switch (family) {
    case NetAddressFamily::UNSPECIFIED:
      return net::ADDRESS_FAMILY_UNSPECIFIED;
    case NetAddressFamily::IPV4:
      return net::ADDRESS_FAMILY_IPV4;
    case NetAddressFamily::IPV6:
      return net::ADDRESS_FAMILY_IPV6;
    default:
      NOTREACHED();
      return net::ADDRESS_FAMILY_UNSPECIFIED;
  }
}

void HostResolverImpl::GetHostAddresses(const mojo::String& host,
                               NetAddressFamily family,
                               const GetHostAddressesCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  net::HostPortPair host_port_pair(host, 0);
  net::HostResolver::RequestInfo request_info(host_port_pair);
  request_info.set_address_family(ConvertFamily(family));
  HostResolverImplJob* job = new HostResolverImplJob(request_info, callback);
  job->Start(resolver_.get());
}

}  // namespace mojo