// Copyright (c) 2019 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 "quiche/quic/qbone/qbone_stream.h"

#include <memory>
#include <optional>
#include <string>
#include <utility>

#include "absl/strings/string_view.h"
#include "quiche/quic/core/crypto/quic_random.h"
#include "quiche/quic/core/quic_session.h"
#include "quiche/quic/core/quic_stream_priority.h"
#include "quiche/quic/core/quic_utils.h"
#include "quiche/quic/platform/api/quic_test.h"
#include "quiche/quic/platform/api/quic_test_loopback.h"
#include "quiche/quic/qbone/qbone_constants.h"
#include "quiche/quic/qbone/qbone_session_base.h"
#include "quiche/quic/test_tools/mock_clock.h"
#include "quiche/quic/test_tools/mock_connection_id_generator.h"
#include "quiche/quic/test_tools/quic_test_utils.h"
#include "quiche/common/simple_buffer_allocator.h"

namespace quic {

namespace {

using ::testing::_;
using ::testing::StrictMock;

// MockQuicSession that does not create streams and writes data from
// QuicStream to a string.
class MockQuicSession : public QboneSessionBase {
 public:
  MockQuicSession(QuicConnection* connection, const QuicConfig& config)
      : QboneSessionBase(connection, nullptr /*visitor*/, config,
                         CurrentSupportedVersions(), nullptr /*writer*/) {}

  ~MockQuicSession() override {}

  // Writes outgoing data from QuicStream to a string.
  QuicConsumedData WritevData(QuicStreamId id, size_t write_length,
                              QuicStreamOffset offset, StreamSendingState state,
                              TransmissionType type,
                              EncryptionLevel level) override {
    if (!writable_) {
      return QuicConsumedData(0, false);
    }

    return QuicConsumedData(write_length, state != StreamSendingState::NO_FIN);
  }

  QboneReadOnlyStream* CreateIncomingStream(QuicStreamId id) override {
    return nullptr;
  }

  // Called by QuicStream when they want to close stream.
  MOCK_METHOD(void, MaybeSendRstStreamFrame,
              (QuicStreamId stream_id, QuicResetStreamError error,
               QuicStreamOffset bytes_written),
              (override));
  MOCK_METHOD(void, MaybeSendStopSendingFrame,
              (QuicStreamId stream_id, QuicResetStreamError error), (override));

  // Sets whether data is written to buffer, or else if this is write blocked.
  void set_writable(bool writable) { writable_ = writable; }

  // Tracks whether the stream is write blocked and its priority.
  void RegisterReliableStream(QuicStreamId stream_id) {
    // The priority effectively does not matter. Put all streams on the same
    // priority.
    write_blocked_streams()->RegisterStream(stream_id,
                                            /* is_static_stream = */ false,
                                            QuicStreamPriority());
  }

  // The session take ownership of the stream.
  void ActivateReliableStream(std::unique_ptr<QuicStream> stream) {
    ActivateStream(std::move(stream));
  }

  std::unique_ptr<QuicCryptoStream> CreateCryptoStream() override {
    return std::make_unique<test::MockQuicCryptoStream>(this);
  }

  MOCK_METHOD(void, ProcessPacketFromPeer, (absl::string_view), (override));
  MOCK_METHOD(void, ProcessPacketFromNetwork, (absl::string_view), (override));

 private:
  // Whether data is written to write_buffer_.
  bool writable_ = true;
};

// Packet writer that does nothing. This is required for QuicConnection but
// isn't used for writing data.
class DummyPacketWriter : public QuicPacketWriter {
 public:
  DummyPacketWriter() {}

  // QuicPacketWriter overrides.
  WriteResult WritePacket(const char* buffer, size_t buf_len,
                          const QuicIpAddress& self_address,
                          const QuicSocketAddress& peer_address,
                          PerPacketOptions* options,
                          const QuicPacketWriterParams& params) override {
    return WriteResult(WRITE_STATUS_ERROR, 0);
  }

  bool IsWriteBlocked() const override { return false; };

  void SetWritable() override {}

  std::optional<int> MessageTooBigErrorCode() const override {
    return std::nullopt;
  }

  QuicByteCount GetMaxPacketSize(
      const QuicSocketAddress& peer_address) const override {
    return 0;
  }

  bool SupportsReleaseTime() const override { return false; }

  bool IsBatchMode() const override { return false; }

  bool SupportsEcn() const override { return false; }

  QuicPacketBuffer GetNextWriteLocation(
      const QuicIpAddress& self_address,
      const QuicSocketAddress& peer_address) override {
    return {nullptr, nullptr};
  }

  WriteResult Flush() override { return WriteResult(WRITE_STATUS_OK, 0); }
};

class QboneReadOnlyStreamTest : public ::testing::Test,
                                public QuicConnectionHelperInterface {
 public:
  void CreateReliableQuicStream() {
    // Arbitrary values for QuicConnection.
    Perspective perspective = Perspective::IS_SERVER;
    bool owns_writer = true;

    alarm_factory_ = std::make_unique<test::MockAlarmFactory>();

    connection_.reset(new QuicConnection(
        test::TestConnectionId(0), QuicSocketAddress(TestLoopback(), 0),
        QuicSocketAddress(TestLoopback(), 0),
        this /*QuicConnectionHelperInterface*/, alarm_factory_.get(),
        new DummyPacketWriter(), owns_writer, perspective,
        ParsedVersionOfIndex(CurrentSupportedVersions(), 0),
        connection_id_generator_));
    clock_.AdvanceTime(QuicTime::Delta::FromSeconds(1));
    session_ = std::make_unique<StrictMock<MockQuicSession>>(connection_.get(),
                                                             QuicConfig());
    session_->Initialize();
    stream_ = new QboneReadOnlyStream(kStreamId, session_.get());
    session_->ActivateReliableStream(
        std::unique_ptr<QboneReadOnlyStream>(stream_));
  }

  ~QboneReadOnlyStreamTest() override {}

  const QuicClock* GetClock() const override { return &clock_; }

  QuicRandom* GetRandomGenerator() override {
    return QuicRandom::GetInstance();
  }

  quiche::QuicheBufferAllocator* GetStreamSendBufferAllocator() override {
    return &buffer_allocator_;
  }

 protected:
  // The QuicSession will take the ownership.
  QboneReadOnlyStream* stream_;
  std::unique_ptr<StrictMock<MockQuicSession>> session_;
  std::unique_ptr<QuicAlarmFactory> alarm_factory_;
  std::unique_ptr<QuicConnection> connection_;
  // Used to implement the QuicConnectionHelperInterface.
  quiche::SimpleBufferAllocator buffer_allocator_;
  MockClock clock_;
  const QuicStreamId kStreamId = QuicUtils::GetFirstUnidirectionalStreamId(
      CurrentSupportedVersions()[0].transport_version, Perspective::IS_CLIENT);
  quic::test::MockConnectionIdGenerator connection_id_generator_;
};

// Read an entire string.
TEST_F(QboneReadOnlyStreamTest, ReadDataWhole) {
  std::string packet = "Stuff";
  CreateReliableQuicStream();
  QuicStreamFrame frame(kStreamId, true, 0, packet);
  EXPECT_CALL(*session_, ProcessPacketFromPeer("Stuff"));
  stream_->OnStreamFrame(frame);
}

// Test buffering.
TEST_F(QboneReadOnlyStreamTest, ReadBuffered) {
  CreateReliableQuicStream();
  std::string packet = "Stuf";
  {
    QuicStreamFrame frame(kStreamId, false, 0, packet);
    stream_->OnStreamFrame(frame);
  }
  // We didn't write 5 bytes yet...

  packet = "f";
  EXPECT_CALL(*session_, ProcessPacketFromPeer("Stuff"));
  {
    QuicStreamFrame frame(kStreamId, true, 4, packet);
    stream_->OnStreamFrame(frame);
  }
}

TEST_F(QboneReadOnlyStreamTest, ReadOutOfOrder) {
  CreateReliableQuicStream();
  std::string packet = "f";
  {
    QuicStreamFrame frame(kStreamId, true, 4, packet);
    stream_->OnStreamFrame(frame);
  }

  packet = "S";
  {
    QuicStreamFrame frame(kStreamId, false, 0, packet);
    stream_->OnStreamFrame(frame);
  }

  packet = "tuf";
  EXPECT_CALL(*session_, ProcessPacketFromPeer("Stuff"));
  {
    QuicStreamFrame frame(kStreamId, false, 1, packet);
    stream_->OnStreamFrame(frame);
  }
}

// Test buffering too many bytes.
TEST_F(QboneReadOnlyStreamTest, ReadBufferedTooLarge) {
  CreateReliableQuicStream();
  std::string packet = "0123456789";
  int iterations = (QboneConstants::kMaxQbonePacketBytes / packet.size()) + 2;
  EXPECT_CALL(*session_, MaybeSendStopSendingFrame(
                             kStreamId, QuicResetStreamError::FromInternal(
                                            QUIC_BAD_APPLICATION_PAYLOAD)));
  EXPECT_CALL(
      *session_,
      MaybeSendRstStreamFrame(
          kStreamId,
          QuicResetStreamError::FromInternal(QUIC_BAD_APPLICATION_PAYLOAD), _));
  for (int i = 0; i < iterations; ++i) {
    QuicStreamFrame frame(kStreamId, i == (iterations - 1), i * packet.size(),
                          packet);
    if (!stream_->reading_stopped()) {
      stream_->OnStreamFrame(frame);
    }
  }
  // We should have nothing written to the network and the stream
  // should have stopped reading.
  EXPECT_TRUE(stream_->reading_stopped());
}

}  // namespace

}  // namespace quic