// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SRC_VIRTUALIZATION_LIB_GRPC_GRPC_VSOCK_STUB_H_
#define SRC_VIRTUALIZATION_LIB_GRPC_GRPC_VSOCK_STUB_H_

#include <fuchsia/virtualization/cpp/fidl.h>
#include <lib/fdio/fd.h>
#include <lib/fpromise/promise.h>

#include "src/virtualization/lib/grpc/fdio_util.h"

#include <grpc++/grpc++.h>

// Connects to a gRPC service listening on cid:port and returns a file
// descriptor for the connection socket.
//
// If you need to dispatch RPCs to the service, consider using
// |NewGrpcVsockStub| instead.
fpromise::promise<zx::socket, zx_status_t> ConnectToGrpcVsockService(
    const fuchsia::virtualization::HostVsockEndpointPtr& socket_endpoint, uint32_t port);

// Creates a new gRPC stub backed by a zx::socket.
template <typename T>
fpromise::result<std::unique_ptr<typename T::Stub>, zx_status_t> NewGrpcStub(zx::socket socket) {
  fbl::unique_fd fd;
  zx_status_t status = fdio_fd_create(socket.release(), fd.reset_and_get_address());
  if (status != ZX_OK) {
    return fpromise::error(status);
  }
  if (SetNonBlocking(fd) != 0) {
    return fpromise::error(ZX_ERR_IO);
  }
  return fpromise::ok(T::NewStub(grpc::CreateInsecureChannelFromFd("vsock", fd.release())));
}

// Connects to a gRPC service listening on DEFAULT_GUEST_CID:port and returns a gRPC
// interface stub for the connection. This stub can be used to dispatch RPCs
// to the server.
template <typename T>
fpromise::promise<std::unique_ptr<typename T::Stub>, zx_status_t> NewGrpcVsockStub(
    const fuchsia::virtualization::HostVsockEndpointPtr& socket_endpoint, uint32_t port) {
  return ConnectToGrpcVsockService(socket_endpoint, port).and_then([](zx::socket& socket) mutable {
    return NewGrpcStub<T>(std::move(socket));
  });
}

#endif  // SRC_VIRTUALIZATION_LIB_GRPC_GRPC_VSOCK_STUB_H_