// 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 GARNET_DRIVERS_BLUETOOTH_LIB_TESTING_TEST_CONTROLLER_H_
#define GARNET_DRIVERS_BLUETOOTH_LIB_TESTING_TEST_CONTROLLER_H_

#include <queue>
#include <vector>

#include <lib/async/dispatcher.h>
#include <lib/fit/function.h>

#include "garnet/drivers/bluetooth/lib/common/byte_buffer.h"
#include "garnet/drivers/bluetooth/lib/hci/hci.h"
#include "garnet/drivers/bluetooth/lib/testing/fake_controller_base.h"
#include "lib/fxl/macros.h"

namespace btlib {
namespace testing {

// A CommandTransaction is used to set up an expectation for a command channel
// packet and the events that should be sent back in response to it.
class CommandTransaction final {
 public:
  CommandTransaction() = default;
  CommandTransaction(const common::ByteBuffer& expected,
                     const std::vector<const common::ByteBuffer*>& replies);

  // Move constructor and assignment operator.
  CommandTransaction(CommandTransaction&& other) = default;
  CommandTransaction& operator=(CommandTransaction&& other) = default;

 private:
  friend class TestController;

  common::DynamicByteBuffer expected_;
  std::queue<common::DynamicByteBuffer> replies_;

  FXL_DISALLOW_COPY_AND_ASSIGN(CommandTransaction);
};

// TestController allows unit tests to set up an expected sequence of HCI
// commands and any events that should be sent back in response. The code
// internally verifies each received HCI command using gtest ASSERT_* macros.
class TestController : public FakeControllerBase {
 public:
  TestController();
  ~TestController() override;

  // Queues a transaction into the TestController's expected command queue. Each
  // packet received through the command channel endpoint will be verified
  // against the next expected transaction in the queue. A mismatch will cause a
  // fatal assertion. On a match, TestController will send back the replies
  // provided in the transaction.
  void QueueCommandTransaction(CommandTransaction transaction);
  void QueueCommandTransaction(
      const common::ByteBuffer& expected,
      const std::vector<const common::ByteBuffer*>& replies);

  // Callback to invoke when a packet is received over the data channel. Care
  // should be taken to ensure that a callback with a reference to test case
  // variables is not invoked when tearing down.
  using DataCallback = fit::function<void(const common::ByteBuffer& packet)>;
  void SetDataCallback(DataCallback callback, async_dispatcher_t* dispatcher);
  void ClearDataCallback();

  // Callback invoked when a transaction completes. Care should be taken to
  // ensure that a callback with a reference to test case variables is not
  // invoked when tearing down.
  void SetTransactionCallback(fit::closure callback,
                              async_dispatcher_t* dispatcher);
  void ClearTransactionCallback();

 private:
  // FakeControllerBase overrides:
  void OnCommandPacketReceived(
      const common::PacketView<hci::CommandHeader>& command_packet) override;
  void OnACLDataPacketReceived(
      const common::ByteBuffer& acl_data_packet) override;

  std::queue<CommandTransaction> cmd_transactions_;
  DataCallback data_callback_;
  async_dispatcher_t* data_dispatcher_;
  fit::closure transaction_callback_;
  async_dispatcher_t* transaction_dispatcher_;

  FXL_DISALLOW_COPY_AND_ASSIGN(TestController);
};

}  // namespace testing
}  // namespace btlib

#endif  // GARNET_DRIVERS_BLUETOOTH_LIB_TESTING_TEST_CONTROLLER_H_