// Copyright 2017 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_CONNECTIVITY_BLUETOOTH_CORE_BT_HOST_L2CAP_FAKE_CHANNEL_TEST_H_
#define SRC_CONNECTIVITY_BLUETOOTH_CORE_BT_HOST_L2CAP_FAKE_CHANNEL_TEST_H_

#include <lib/gtest/test_loop_fixture.h>

#include <memory>

#include <fbl/macros.h>

#include "src/connectivity/bluetooth/core/bt-host/hci-spec/protocol.h"
#include "src/connectivity/bluetooth/core/bt-host/l2cap/fake_channel.h"
#include "src/connectivity/bluetooth/core/bt-host/l2cap/l2cap_defs.h"

namespace bt::l2cap::testing {

// Provides a common GTest harness base class for protocols tests that operate
// over a L2CAP channel. This harness provides:
//
//   * A simple way to initialize and access a FakeChannel.
//   * Basic command<->response expectation.
class FakeChannelTest : public ::gtest::TestLoopFixture {
 public:
  FakeChannelTest() = default;
  ~FakeChannelTest() override = default;

 protected:
  struct ChannelOptions {
    explicit ChannelOptions(ChannelId id, uint16_t mtu = kDefaultMTU)
        : ChannelOptions(id, id, mtu) {}
    ChannelOptions(ChannelId id, ChannelId remote_id, uint16_t mtu)
        : id(id), remote_id(remote_id), mtu(mtu) {}

    ChannelId id;
    ChannelId remote_id;
    uint16_t mtu;
    hci_spec::ConnectionHandle conn_handle = 0x0001;
    bt::LinkType link_type = bt::LinkType::kLE;
  };

  void SetUp() override;

  // Creates a new FakeChannel and returns it. A fxl::WeakPtr to the returned
  // channel is stored internally so that the returned channel can be accessed
  // by tests even if its ownership is passed outside of the test harness.
  fbl::RefPtr<FakeChannel> CreateFakeChannel(const ChannelOptions& options);

  // Runs the event loop and returns true if |expected| is received within a 10
  // second period.
  //
  // Returns false if no such response is received or no FakeChannel has been
  // initialized via CreateFakeChannel().
  //
  // NOTE: This overwrites the underlying FakeChannel's "send callback" by
  // calling FakeChannel::SetSendCallback().
  bool Expect(const ByteBuffer& expected);

  // Emulates the receipt of |packet| and returns true if a response that
  // matches |expected_response| is sent back over the underlying FakeChannel.
  // Returns false if no such response is received or no FakeChannel has been
  // initialized via CreateFakeChannel().
  //
  // NOTE: This overwrites the underlying FakeChannel's "send callback" by
  // calling FakeChannel::SetSendCallback().
  bool ReceiveAndExpect(const ByteBuffer& packet, const ByteBuffer& expected_response);

  fxl::WeakPtr<FakeChannel> fake_chan() const { return fake_chan_; }

  void set_fake_chan(fxl::WeakPtr<FakeChannel> chan) { fake_chan_ = chan; }

 private:
  // Helper that sets a reception expectation callback with |expected| then sends |packet| if it is
  // not std::nullopt, returning whether |expected| was received when the test loop run until idle.
  bool ExpectAfterMaybeReceiving(std::optional<BufferView> packet, const ByteBuffer& expected);

  fxl::WeakPtr<FakeChannel> fake_chan_;

  DISALLOW_COPY_AND_ASSIGN_ALLOW_MOVE(FakeChannelTest);
};

}  // namespace bt::l2cap::testing

#endif  // SRC_CONNECTIVITY_BLUETOOTH_CORE_BT_HOST_L2CAP_FAKE_CHANNEL_TEST_H_