//
// detail/winrt_resolver_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP
#define ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"

#if defined(ASIO_WINDOWS_RUNTIME)

#include "asio/ip/basic_resolver_query.hpp"
#include "asio/ip/basic_resolver_results.hpp"
#include "asio/post.hpp"
#include "asio/detail/bind_handler.hpp"
#include "asio/detail/memory.hpp"
#include "asio/detail/socket_ops.hpp"
#include "asio/detail/winrt_async_manager.hpp"
#include "asio/detail/winrt_resolve_op.hpp"
#include "asio/detail/winrt_utils.hpp"

#if defined(ASIO_HAS_IOCP)
# include "asio/detail/win_iocp_io_context.hpp"
#else // defined(ASIO_HAS_IOCP)
# include "asio/detail/scheduler.hpp"
#endif // defined(ASIO_HAS_IOCP)

#include "asio/detail/push_options.hpp"

namespace asio {
namespace detail {

template <typename Protocol>
class winrt_resolver_service :
  public execution_context_service_base<winrt_resolver_service<Protocol> >
{
public:
  // The implementation type of the resolver. A cancellation token is used to
  // indicate to the asynchronous operation that the operation has been
  // cancelled.
  typedef socket_ops::shared_cancel_token_type implementation_type;

  // The endpoint type.
  typedef typename Protocol::endpoint endpoint_type;

  // The query type.
  typedef asio::ip::basic_resolver_query<Protocol> query_type;

  // The results type.
  typedef asio::ip::basic_resolver_results<Protocol> results_type;

  // Constructor.
  winrt_resolver_service(execution_context& context)
    : execution_context_service_base<
        winrt_resolver_service<Protocol> >(context),
      scheduler_(use_service<scheduler_impl>(context)),
      async_manager_(use_service<winrt_async_manager>(context))
  {
  }

  // Destructor.
  ~winrt_resolver_service()
  {
  }

  // Destroy all user-defined handler objects owned by the service.
  void shutdown()
  {
  }

  // Perform any fork-related housekeeping.
  void notify_fork(execution_context::fork_event)
  {
  }

  // Construct a new resolver implementation.
  void construct(implementation_type&)
  {
  }

  // Move-construct a new resolver implementation.
  void move_construct(implementation_type&,
      implementation_type&)
  {
  }

  // Move-assign from another resolver implementation.
  void move_assign(implementation_type&,
      winrt_resolver_service&, implementation_type&)
  {
  }

  // Destroy a resolver implementation.
  void destroy(implementation_type&)
  {
  }

  // Cancel pending asynchronous operations.
  void cancel(implementation_type&)
  {
  }

  // Resolve a query to a list of entries.
  results_type resolve(implementation_type&,
      const query_type& query, asio::error_code& ec)
  {
    try
    {
      using namespace Windows::Networking::Sockets;
      auto endpoint_pairs = async_manager_.sync(
          DatagramSocket::GetEndpointPairsAsync(
            winrt_utils::host_name(query.host_name()),
            winrt_utils::string(query.service_name())), ec);

      if (ec)
        return results_type();

      return results_type::create(
          endpoint_pairs, query.hints(),
          query.host_name(), query.service_name());
    }
    catch (Platform::Exception^ e)
    {
      ec = asio::error_code(e->HResult,
          asio::system_category());
      return results_type();
    }
  }

  // Asynchronously resolve a query to a list of entries.
  template <typename Handler, typename IoExecutor>
  void async_resolve(implementation_type& impl, const query_type& query,
      Handler& handler, const IoExecutor& io_ex)
  {
    bool is_continuation =
      asio_handler_cont_helpers::is_continuation(handler);

    // Allocate and construct an operation to wrap the handler.
    typedef winrt_resolve_op<Protocol, Handler, IoExecutor> op;
    typename op::ptr p = { asio::detail::addressof(handler),
      op::ptr::allocate(handler), 0 };
    p.p = new (p.v) op(query, handler, io_ex);

    ASIO_HANDLER_CREATION((scheduler_.context(),
          *p.p, "resolver", &impl, 0, "async_resolve"));
    (void)impl;

    try
    {
      using namespace Windows::Networking::Sockets;
      async_manager_.async(DatagramSocket::GetEndpointPairsAsync(
            winrt_utils::host_name(query.host_name()),
            winrt_utils::string(query.service_name())), p.p);
      p.v = p.p = 0;
    }
    catch (Platform::Exception^ e)
    {
      p.p->ec_ = asio::error_code(
          e->HResult, asio::system_category());
      scheduler_.post_immediate_completion(p.p, is_continuation);
      p.v = p.p = 0;
    }
  }

  // Resolve an endpoint to a list of entries.
  results_type resolve(implementation_type&,
      const endpoint_type&, asio::error_code& ec)
  {
    ec = asio::error::operation_not_supported;
    return results_type();
  }

  // Asynchronously resolve an endpoint to a list of entries.
  template <typename Handler, typename IoExecutor>
  void async_resolve(implementation_type&, const endpoint_type&,
      Handler& handler, const IoExecutor& io_ex)
  {
    asio::error_code ec = asio::error::operation_not_supported;
    const results_type results;
    asio::post(io_ex, detail::bind_handler(handler, ec, results));
  }

private:
  // The scheduler implementation used for delivering completions.
#if defined(ASIO_HAS_IOCP)
  typedef class win_iocp_io_context scheduler_impl;
#else
  typedef class scheduler scheduler_impl;
#endif
  scheduler_impl& scheduler_;

  winrt_async_manager& async_manager_;
};

} // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // defined(ASIO_WINDOWS_RUNTIME)

#endif // ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP
