// Copyright 2022 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/pwpb/internal/method.h"

#include <array>

#include "gtest/gtest.h"
#include "pw_rpc/internal/lock.h"
#include "pw_rpc/internal/method_impl_tester.h"
#include "pw_rpc/internal/test_utils.h"
#include "pw_rpc/pwpb/internal/method_union.h"
#include "pw_rpc/service.h"
#include "pw_rpc_pwpb_private/internal_test_utils.h"
#include "pw_rpc_test_protos/test.pwpb.h"

PW_MODIFY_DIAGNOSTICS_PUSH();
PW_MODIFY_DIAGNOSTIC(ignored, "-Wmissing-field-initializers");

namespace pw::rpc::internal {
namespace {

using std::byte;

struct FakePb {};

// Create a fake service for use with the MethodImplTester.
class TestPwpbService final : public Service {
 public:
  // Unary signatures

  Status Unary(const FakePb&, FakePb&) { return Status(); }

  static Status StaticUnary(const FakePb&, FakePb&) { return Status(); }

  void AsyncUnary(const FakePb&, PwpbUnaryResponder<FakePb>&) {}

  static void StaticAsyncUnary(const FakePb&, PwpbUnaryResponder<FakePb>&) {}

  Status UnaryWrongArg(FakePb&, FakePb&) { return Status(); }

  static void StaticUnaryVoidReturn(const FakePb&, FakePb&) {}

  // Server streaming signatures

  void ServerStreaming(const FakePb&, PwpbServerWriter<FakePb>&) {}

  static void StaticServerStreaming(const FakePb&, PwpbServerWriter<FakePb>&) {}

  int ServerStreamingBadReturn(const FakePb&, PwpbServerWriter<FakePb>&) {
    return 5;
  }

  static void StaticServerStreamingMissingArg(PwpbServerWriter<FakePb>&) {}

  // Client streaming signatures

  void ClientStreaming(PwpbServerReader<FakePb, FakePb>&) {}

  static void StaticClientStreaming(PwpbServerReader<FakePb, FakePb>&) {}

  int ClientStreamingBadReturn(PwpbServerReader<FakePb, FakePb>&) { return 0; }

  static void StaticClientStreamingMissingArg() {}

  // Bidirectional streaming signatures

  void BidirectionalStreaming(PwpbServerReaderWriter<FakePb, FakePb>&) {}

  static void StaticBidirectionalStreaming(
      PwpbServerReaderWriter<FakePb, FakePb>&) {}

  int BidirectionalStreamingBadReturn(PwpbServerReaderWriter<FakePb, FakePb>&) {
    return 0;
  }

  static void StaticBidirectionalStreamingMissingArg() {}
};

struct WrongPb;

// Test matches() rejects incorrect request/response types.
// clang-format off
static_assert(!PwpbMethod::template matches<&TestPwpbService::Unary, WrongPb, FakePb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::Unary, FakePb, WrongPb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::Unary, WrongPb, WrongPb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::StaticUnary, FakePb, WrongPb>());

static_assert(!PwpbMethod::template matches<&TestPwpbService::ServerStreaming, WrongPb, FakePb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::StaticServerStreaming, FakePb, WrongPb>());

static_assert(!PwpbMethod::template matches<&TestPwpbService::ClientStreaming, WrongPb, FakePb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::StaticClientStreaming, FakePb, WrongPb>());

static_assert(!PwpbMethod::template matches<&TestPwpbService::BidirectionalStreaming, WrongPb, FakePb>());
static_assert(!PwpbMethod::template matches<&TestPwpbService::StaticBidirectionalStreaming, FakePb, WrongPb>());
// clang-format on

static_assert(MethodImplTests<PwpbMethod, TestPwpbService>().Pass(
    MatchesTypes<FakePb, FakePb>(),
    std::tuple<const PwpbMethodSerde&>(kPwpbMethodSerde<nullptr, nullptr>)));

template <typename Impl>
class FakeServiceBase : public Service {
 public:
  FakeServiceBase(uint32_t id) : Service(id, kMethods) {}

  static constexpr std::array<PwpbMethodUnion, 5> kMethods = {
      PwpbMethod::SynchronousUnary<&Impl::DoNothing>(
          10u,
          kPwpbMethodSerde<&pw::rpc::test::Empty::kMessageFields,
                           &pw::rpc::test::Empty::kMessageFields>),
      PwpbMethod::AsynchronousUnary<&Impl::AddFive>(
          11u,
          kPwpbMethodSerde<&pw::rpc::test::TestRequest::kMessageFields,
                           &pw::rpc::test::TestResponse::kMessageFields>),
      PwpbMethod::ServerStreaming<&Impl::StartStream>(
          12u,
          kPwpbMethodSerde<&pw::rpc::test::TestRequest::kMessageFields,
                           &pw::rpc::test::TestResponse::kMessageFields>),
      PwpbMethod::ClientStreaming<&Impl::ClientStream>(
          13u,
          kPwpbMethodSerde<&pw::rpc::test::TestRequest::kMessageFields,
                           &pw::rpc::test::TestResponse::kMessageFields>),
      PwpbMethod::BidirectionalStreaming<&Impl::BidirectionalStream>(
          14u,
          kPwpbMethodSerde<&pw::rpc::test::TestRequest::kMessageFields,
                           &pw::rpc::test::TestResponse::kMessageFields>)};
};

class FakeService : public FakeServiceBase<FakeService> {
 public:
  FakeService(uint32_t id) : FakeServiceBase(id) {}

  Status DoNothing(const pw::rpc::test::Empty::Message&,
                   pw::rpc::test::Empty::Message&) {
    return Status::Unknown();
  }

  void AddFive(
      const pw::rpc::test::TestRequest::Message& request,
      PwpbUnaryResponder<pw::rpc::test::TestResponse::Message>& responder) {
    last_request = request;

    if (fail_to_encode_async_unary_response) {
      pw::rpc::test::TestResponse::Message response = {};
      response.repeated_field.SetEncoder(
          [](const pw::rpc::test::TestResponse::StreamEncoder&) {
            return Status::Internal();
          });
      ASSERT_EQ(OkStatus(), responder.Finish(response, Status::NotFound()));
    } else {
      ASSERT_EQ(
          OkStatus(),
          responder.Finish({.value = static_cast<int32_t>(request.integer + 5)},
                           Status::Unauthenticated()));
    }
  }

  void StartStream(
      const pw::rpc::test::TestRequest::Message& request,
      PwpbServerWriter<pw::rpc::test::TestResponse::Message>& writer) {
    last_request = request;
    last_writer = std::move(writer);
  }

  void ClientStream(
      PwpbServerReader<pw::rpc::test::TestRequest::Message,
                       pw::rpc::test::TestResponse::Message>& reader) {
    last_reader = std::move(reader);
  }

  void BidirectionalStream(
      PwpbServerReaderWriter<pw::rpc::test::TestRequest::Message,
                             pw::rpc::test::TestResponse::Message>&
          reader_writer) {
    last_reader_writer = std::move(reader_writer);
  }

  bool fail_to_encode_async_unary_response = false;

  pw::rpc::test::TestRequest::Message last_request;
  PwpbServerWriter<pw::rpc::test::TestResponse::Message> last_writer;
  PwpbServerReader<pw::rpc::test::TestRequest::Message,
                   pw::rpc::test::TestResponse::Message>
      last_reader;
  PwpbServerReaderWriter<pw::rpc::test::TestRequest::Message,
                         pw::rpc::test::TestResponse::Message>
      last_reader_writer;
};

constexpr const PwpbMethod& kSyncUnary =
    std::get<0>(FakeServiceBase<FakeService>::kMethods).pwpb_method();
constexpr const PwpbMethod& kAsyncUnary =
    std::get<1>(FakeServiceBase<FakeService>::kMethods).pwpb_method();
constexpr const PwpbMethod& kServerStream =
    std::get<2>(FakeServiceBase<FakeService>::kMethods).pwpb_method();
constexpr const PwpbMethod& kClientStream =
    std::get<3>(FakeServiceBase<FakeService>::kMethods).pwpb_method();
constexpr const PwpbMethod& kBidirectionalStream =
    std::get<4>(FakeServiceBase<FakeService>::kMethods).pwpb_method();

TEST(PwpbMethod, AsyncUnaryRpc_SendsResponse) {
  PW_ENCODE_PB(
      pw::rpc::test::TestRequest, request, .integer = 123, .status_code = 0);

  ServerContextForTest<FakeService> context(kAsyncUnary);
  rpc_lock().lock();
  kAsyncUnary.Invoke(context.get(), context.request(request));

  const Packet& response = context.output().last_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, context.service().last_request.integer);
}

TEST(PwpbMethod, SyncUnaryRpc_InvalidPayload_SendsError) {
  std::array<byte, 8> bad_payload{byte{0xFF}, byte{0xAA}, byte{0xDD}};

  ServerContextForTest<FakeService> context(kSyncUnary);
  rpc_lock().lock();
  kSyncUnary.Invoke(context.get(), context.request(bad_payload));

  const Packet& packet = context.output().last_packet();
  EXPECT_EQ(PacketType::SERVER_ERROR, packet.type());
  EXPECT_EQ(Status::DataLoss(), packet.status());
  EXPECT_EQ(context.service_id(), packet.service_id());
  EXPECT_EQ(kSyncUnary.id(), packet.method_id());
}

TEST(PwpbMethod, AsyncUnaryRpc_ResponseEncodingFails_SendsInternalError) {
  constexpr int64_t value = 0x7FFFFFFF'FFFFFF00ll;
  PW_ENCODE_PB(
      pw::rpc::test::TestRequest, request, .integer = value, .status_code = 0);

  ServerContextForTest<FakeService> context(kAsyncUnary);
  context.service().fail_to_encode_async_unary_response = true;

  rpc_lock().lock();
  kAsyncUnary.Invoke(context.get(), context.request(request));

  const Packet& packet = context.output().last_packet();
  EXPECT_EQ(PacketType::SERVER_ERROR, packet.type());
  EXPECT_EQ(Status::Internal(), packet.status());
  EXPECT_EQ(context.service_id(), packet.service_id());
  EXPECT_EQ(kAsyncUnary.id(), packet.method_id());

  EXPECT_EQ(value, context.service().last_request.integer);
}

TEST(PwpbMethod, ServerStreamingRpc_SendsNothingWhenInitiallyCalled) {
  PW_ENCODE_PB(
      pw::rpc::test::TestRequest, request, .integer = 555, .status_code = 0);

  ServerContextForTest<FakeService> context(kServerStream);

  rpc_lock().lock();
  kServerStream.Invoke(context.get(), context.request(request));

  EXPECT_EQ(0u, context.output().total_packets());
  EXPECT_EQ(555, context.service().last_request.integer);
}

TEST(PwpbMethod, ServerWriter_SendsResponse) {
  ServerContextForTest<FakeService> context(kServerStream);

  rpc_lock().lock();
  kServerStream.Invoke(context.get(), context.request({}));

  EXPECT_EQ(OkStatus(), context.service().last_writer.Write({.value = 100}));

  PW_ENCODE_PB(pw::rpc::test::TestResponse, payload, .value = 100);
  std::array<byte, 128> encoded_response = {};
  auto encoded = context.server_stream(payload).Encode(encoded_response);
  ASSERT_EQ(OkStatus(), encoded.status());

  ConstByteSpan sent_payload = context.output().last_packet().payload();
  EXPECT_TRUE(std::equal(payload.begin(),
                         payload.end(),
                         sent_payload.begin(),
                         sent_payload.end()));
}

TEST(PwpbMethod, ServerWriter_WriteWhenClosed_ReturnsFailedPrecondition) {
  ServerContextForTest<FakeService> context(kServerStream);

  rpc_lock().lock();
  kServerStream.Invoke(context.get(), context.request({}));

  EXPECT_EQ(OkStatus(), context.service().last_writer.Finish());
  EXPECT_TRUE(context.service()
                  .last_writer.Write({.value = 100})
                  .IsFailedPrecondition());
}

TEST(PwpbMethod, ServerWriter_WriteAfterMoved_ReturnsFailedPrecondition) {
  ServerContextForTest<FakeService> context(kServerStream);

  rpc_lock().lock();
  kServerStream.Invoke(context.get(), context.request({}));
  PwpbServerWriter<pw::rpc::test::TestResponse::Message> new_writer =
      std::move(context.service().last_writer);

  EXPECT_EQ(OkStatus(), new_writer.Write({.value = 100}));

  EXPECT_EQ(Status::FailedPrecondition(),
            context.service().last_writer.Write({.value = 100}));
  EXPECT_EQ(Status::FailedPrecondition(),
            context.service().last_writer.Finish());

  EXPECT_EQ(OkStatus(), new_writer.Finish());
}

TEST(PwpbMethod, ServerStreamingRpc_ResponseEncodingFails_InternalError) {
  ServerContextForTest<FakeService> context(kServerStream);

  rpc_lock().lock();
  kServerStream.Invoke(context.get(), context.request({}));

  EXPECT_EQ(OkStatus(), context.service().last_writer.Write({}));

  pw::rpc::test::TestResponse::Message response = {};
  response.repeated_field.SetEncoder(
      [](const pw::rpc::test::TestResponse::StreamEncoder&) {
        return Status::Internal();
      });
  EXPECT_EQ(Status::Internal(), context.service().last_writer.Write(response));
}

TEST(PwpbMethod, ServerReader_HandlesRequests) {
  ServerContextForTest<FakeService> context(kClientStream);

  rpc_lock().lock();
  kClientStream.Invoke(context.get(), context.request({}));

  pw::rpc::test::TestRequest::Message request_struct{};
  context.service().last_reader.set_on_next(
      [&request_struct](const pw::rpc::test::TestRequest::Message& req) {
        request_struct = req;
      });

  PW_ENCODE_PB(pw::rpc::test::TestRequest,
               request,
               .integer = 1 << 30,
               .status_code = 9);
  std::array<byte, 128> encoded_request = {};
  auto encoded = context.client_stream(request).Encode(encoded_request);
  ASSERT_EQ(OkStatus(), encoded.status());
  ASSERT_EQ(OkStatus(),
            context.server().ProcessPacket(*encoded, context.output()));

  EXPECT_EQ(request_struct.integer, 1 << 30);
  EXPECT_EQ(request_struct.status_code, 9u);
}

TEST(PwpbMethod, ServerReaderWriter_WritesResponses) {
  ServerContextForTest<FakeService> context(kBidirectionalStream);

  rpc_lock().lock();
  kBidirectionalStream.Invoke(context.get(), context.request({}));

  EXPECT_EQ(OkStatus(),
            context.service().last_reader_writer.Write({.value = 100}));

  PW_ENCODE_PB(pw::rpc::test::TestResponse, payload, .value = 100);
  std::array<byte, 128> encoded_response = {};
  auto encoded = context.server_stream(payload).Encode(encoded_response);
  ASSERT_EQ(OkStatus(), encoded.status());

  ConstByteSpan sent_payload = context.output().last_packet().payload();
  EXPECT_TRUE(std::equal(payload.begin(),
                         payload.end(),
                         sent_payload.begin(),
                         sent_payload.end()));
}

TEST(PwpbMethod, ServerReaderWriter_HandlesRequests) {
  ServerContextForTest<FakeService> context(kBidirectionalStream);

  rpc_lock().lock();
  kBidirectionalStream.Invoke(context.get(), context.request({}));

  pw::rpc::test::TestRequest::Message request_struct{};
  context.service().last_reader_writer.set_on_next(
      [&request_struct](const pw::rpc::test::TestRequest::Message& req) {
        request_struct = req;
      });

  PW_ENCODE_PB(pw::rpc::test::TestRequest,
               request,
               .integer = 1 << 29,
               .status_code = 8);
  std::array<byte, 128> encoded_request = {};
  auto encoded = context.client_stream(request).Encode(encoded_request);
  ASSERT_EQ(OkStatus(), encoded.status());
  ASSERT_EQ(OkStatus(),
            context.server().ProcessPacket(*encoded, context.output()));

  EXPECT_EQ(request_struct.integer, 1 << 29);
  EXPECT_EQ(request_struct.status_code, 8u);
}

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

PW_MODIFY_DIAGNOSTICS_POP();