// Copyright 2020 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#include "pw_rpc/internal/nanopb_method_union.h"

#include <array>

#include "gtest/gtest.h"
#include "pw_rpc_nanopb_private/internal_test_utils.h"
#include "pw_rpc_private/internal_test_utils.h"
#include "pw_rpc_test_protos/test.pb.h"

namespace pw::rpc::internal {
namespace {

using std::byte;

template <typename Implementation>
class FakeGeneratedService : public Service {
 public:
  constexpr FakeGeneratedService(uint32_t id) : Service(id, kMethods) {}

  static constexpr std::array<NanopbMethodUnion, 4> kMethods = {
      GetNanopbOrRawMethodFor<&Implementation::DoNothing, MethodType::kUnary>(
          10u, pw_rpc_test_Empty_fields, pw_rpc_test_Empty_fields),
      GetNanopbOrRawMethodFor<&Implementation::RawStream,
                              MethodType::kServerStreaming>(
          11u, pw_rpc_test_TestRequest_fields, pw_rpc_test_TestResponse_fields),
      GetNanopbOrRawMethodFor<&Implementation::AddFive, MethodType::kUnary>(
          12u, pw_rpc_test_TestRequest_fields, pw_rpc_test_TestResponse_fields),
      GetNanopbOrRawMethodFor<&Implementation::StartStream,
                              MethodType::kServerStreaming>(
          13u, pw_rpc_test_TestRequest_fields, pw_rpc_test_TestResponse_fields),
  };
};

pw_rpc_test_TestRequest last_request;
ServerWriter<pw_rpc_test_TestResponse> last_writer;
RawServerWriter last_raw_writer;

class FakeGeneratedServiceImpl
    : public FakeGeneratedService<FakeGeneratedServiceImpl> {
 public:
  FakeGeneratedServiceImpl(uint32_t id) : FakeGeneratedService(id) {}

  Status AddFive(ServerContext&,
                 const pw_rpc_test_TestRequest& request,
                 pw_rpc_test_TestResponse& response) {
    last_request = request;
    response.value = request.integer + 5;
    return Status::Unauthenticated();
  }

  StatusWithSize DoNothing(ServerContext&, ConstByteSpan, ByteSpan) {
    return StatusWithSize::Unknown();
  }

  void RawStream(ServerContext&, ConstByteSpan, RawServerWriter& writer) {
    last_raw_writer = std::move(writer);
  }

  void StartStream(ServerContext&,
                   const pw_rpc_test_TestRequest& request,
                   ServerWriter<pw_rpc_test_TestResponse>& writer) {
    last_request = request;
    last_writer = std::move(writer);
  }
};

TEST(NanopbMethodUnion, Raw_CallsUnaryMethod) {
  const Method& method =
      std::get<0>(FakeGeneratedServiceImpl::kMethods).method();
  ServerContextForTest<FakeGeneratedServiceImpl> context(method);
  method.Invoke(context.get(), context.packet({}));

  const Packet& response = context.output().sent_packet();
  EXPECT_EQ(response.status(), Status::Unknown());
}

TEST(NanopbMethodUnion, Raw_CallsServerStreamingMethod) {
  PW_ENCODE_PB(
      pw_rpc_test_TestRequest, request, .integer = 555, .status_code = 0);

  const Method& method =
      std::get<1>(FakeGeneratedServiceImpl::kMethods).method();
  ServerContextForTest<FakeGeneratedServiceImpl> context(method);

  method.Invoke(context.get(), context.packet(request));

  EXPECT_TRUE(last_raw_writer.open());
  EXPECT_EQ(OkStatus(), last_raw_writer.Finish());
  EXPECT_EQ(context.output().sent_packet().type(),
            PacketType::SERVER_STREAM_END);
}

TEST(NanopbMethodUnion, Nanopb_CallsUnaryMethod) {
  PW_ENCODE_PB(
      pw_rpc_test_TestRequest, request, .integer = 123, .status_code = 3);

  const Method& method =
      std::get<2>(FakeGeneratedServiceImpl::kMethods).method();
  ServerContextForTest<FakeGeneratedServiceImpl> context(method);
  method.Invoke(context.get(), context.packet(request));

  const Packet& response = context.output().sent_packet();
  EXPECT_EQ(response.status(), Status::Unauthenticated());

  // Field 1 (encoded as 1 << 3) with 128 as the value.
  constexpr std::byte expected[]{
      std::byte{0x08}, std::byte{0x80}, std::byte{0x01}};

  EXPECT_EQ(sizeof(expected), response.payload().size());
  EXPECT_EQ(0,
            std::memcmp(expected, response.payload().data(), sizeof(expected)));

  EXPECT_EQ(123, last_request.integer);
  EXPECT_EQ(3u, last_request.status_code);
}

TEST(NanopbMethodUnion, Nanopb_CallsServerStreamingMethod) {
  PW_ENCODE_PB(
      pw_rpc_test_TestRequest, request, .integer = 555, .status_code = 0);

  const Method& method =
      std::get<3>(FakeGeneratedServiceImpl::kMethods).method();
  ServerContextForTest<FakeGeneratedServiceImpl> context(method);

  method.Invoke(context.get(), context.packet(request));

  EXPECT_EQ(555, last_request.integer);
  EXPECT_TRUE(last_writer.open());

  EXPECT_EQ(OkStatus(), last_writer.Finish());
  EXPECT_EQ(context.output().sent_packet().type(),
            PacketType::SERVER_STREAM_END);
}

}  // namespace
}  // namespace pw::rpc::internal