// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "device/bluetooth/dbus/bluetooth_gatt_descriptor_client.h"

#include <stddef.h>

#include "base/compiler_specific.h"
#include "base/containers/to_vector.h"
#include "base/functional/bind.h"
#include "base/logging.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/values.h"
#include "dbus/bus.h"
#include "dbus/object_manager.h"
#include "dbus/values_util.h"
#include "third_party/cros_system_api/dbus/service_constants.h"

namespace bluez {

namespace {

// TODO(armansito): Move this constant to cros_system_api.
const char kValueProperty[] = "Value";

}  // namespace

// static
const char BluetoothGattDescriptorClient::kNoResponseError[] =
    "org.chromium.Error.NoResponse";
// static
const char BluetoothGattDescriptorClient::kUnknownDescriptorError[] =
    "org.chromium.Error.UnknownDescriptor";

BluetoothGattDescriptorClient::Properties::Properties(
    dbus::ObjectProxy* object_proxy,
    const std::string& interface_name,
    const PropertyChangedCallback& callback)
    : dbus::PropertySet(object_proxy, interface_name, callback) {
  RegisterProperty(bluetooth_gatt_descriptor::kUUIDProperty, &uuid);
  RegisterProperty(bluetooth_gatt_descriptor::kCharacteristicProperty,
                   &characteristic);
  RegisterProperty(kValueProperty, &value);
}

BluetoothGattDescriptorClient::Properties::~Properties() = default;

// The BluetoothGattDescriptorClient implementation used in production.
class BluetoothGattDescriptorClientImpl
    : public BluetoothGattDescriptorClient,
      public dbus::ObjectManager::Interface {
 public:
  BluetoothGattDescriptorClientImpl() : object_manager_(nullptr) {}

  BluetoothGattDescriptorClientImpl(const BluetoothGattDescriptorClientImpl&) =
      delete;
  BluetoothGattDescriptorClientImpl& operator=(
      const BluetoothGattDescriptorClientImpl&) = delete;

  ~BluetoothGattDescriptorClientImpl() override {
    object_manager_->UnregisterInterface(
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface);
  }

  // BluetoothGattDescriptorClientImpl override.
  void AddObserver(BluetoothGattDescriptorClient::Observer* observer) override {
    DCHECK(observer);
    observers_.AddObserver(observer);
  }

  // BluetoothGattDescriptorClientImpl override.
  void RemoveObserver(
      BluetoothGattDescriptorClient::Observer* observer) override {
    DCHECK(observer);
    observers_.RemoveObserver(observer);
  }

  // BluetoothGattDescriptorClientImpl override.
  std::vector<dbus::ObjectPath> GetDescriptors() override {
    DCHECK(object_manager_);
    return object_manager_->GetObjectsWithInterface(
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface);
  }

  // BluetoothGattDescriptorClientImpl override.
  Properties* GetProperties(const dbus::ObjectPath& object_path) override {
    DCHECK(object_manager_);
    return static_cast<Properties*>(object_manager_->GetProperties(
        object_path,
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface));
  }

  // BluetoothGattDescriptorClientImpl override.
  void ReadValue(const dbus::ObjectPath& object_path,
                 ValueCallback callback,
                 ErrorCallback error_callback) override {
    dbus::ObjectProxy* object_proxy =
        object_manager_->GetObjectProxy(object_path);
    if (!object_proxy) {
      std::move(error_callback).Run(kUnknownDescriptorError, "");
      return;
    }

    dbus::MethodCall method_call(
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface,
        bluetooth_gatt_descriptor::kReadValue);

    // Append empty option dict
    dbus::MessageWriter writer(&method_call);
    dbus::AppendValueData(&writer, base::DictValue());

    object_proxy->CallMethodWithErrorResponse(
        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
        base::BindOnce(&BluetoothGattDescriptorClientImpl::OnReadValueResponse,
                       weak_ptr_factory_.GetWeakPtr(), std::move(callback),
                       std::move(error_callback)));
  }

  // BluetoothGattDescriptorClientImpl override.
  void WriteValue(const dbus::ObjectPath& object_path,
                  base::span<const uint8_t> value,
                  base::OnceClosure callback,
                  ErrorCallback error_callback) override {
    dbus::ObjectProxy* object_proxy =
        object_manager_->GetObjectProxy(object_path);
    if (!object_proxy) {
      std::move(error_callback).Run(kUnknownDescriptorError, "");
      return;
    }

    dbus::MethodCall method_call(
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface,
        bluetooth_gatt_descriptor::kWriteValue);
    dbus::MessageWriter writer(&method_call);
    writer.AppendArrayOfBytes(value);

    // Append empty option dict
    dbus::AppendValueData(&writer, base::DictValue());

    object_proxy->CallMethodWithErrorResponse(
        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
        base::BindOnce(&BluetoothGattDescriptorClientImpl::OnWriteValueResponse,
                       weak_ptr_factory_.GetWeakPtr(), std::move(callback),
                       std::move(error_callback)));
  }

  // dbus::ObjectManager::Interface override.
  dbus::PropertySet* CreateProperties(
      dbus::ObjectProxy* object_proxy,
      const dbus::ObjectPath& object_path,
      const std::string& interface_name) override {
    return new Properties(
        object_proxy, interface_name,
        base::BindRepeating(
            &BluetoothGattDescriptorClientImpl::OnPropertyChanged,
            weak_ptr_factory_.GetWeakPtr(), object_path));
  }

  // dbus::ObjectManager::Interface override.
  void ObjectAdded(const dbus::ObjectPath& object_path,
                   const std::string& interface_name) override {
    DVLOG(2) << "Remote GATT descriptor added: " << object_path.value();
    for (auto& observer : observers_)
      observer.GattDescriptorAdded(object_path);
  }

  // dbus::ObjectManager::Interface override.
  void ObjectRemoved(const dbus::ObjectPath& object_path,
                     const std::string& interface_name) override {
    DVLOG(2) << "Remote GATT descriptor removed: " << object_path.value();
    for (auto& observer : observers_)
      observer.GattDescriptorRemoved(object_path);
  }

 protected:
  // bluez::DBusClient override.
  void Init(dbus::Bus* bus,
            const std::string& bluetooth_service_name) override {
    object_manager_ = bus->GetObjectManager(
        bluetooth_service_name,
        dbus::ObjectPath(
            bluetooth_object_manager::kBluetoothObjectManagerServicePath));
    object_manager_->RegisterInterface(
        bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface, this);
  }

 private:
  // Called by dbus::PropertySet when a property value is changed, either by
  // result of a signal or response to a GetAll() or Get() call. Informs
  // observers.
  virtual void OnPropertyChanged(const dbus::ObjectPath& object_path,
                                 const std::string& property_name) {
    DVLOG(2) << "Remote GATT descriptor property changed: "
             << object_path.value() << ": " << property_name;
    for (auto& observer : observers_)
      observer.GattDescriptorPropertyChanged(object_path, property_name);
  }

  void OnWriteValueResponse(base::OnceClosure callback,
                            ErrorCallback error_callback,
                            dbus::Response* response,
                            dbus::ErrorResponse* error_response) {
    if (response) {
      std::move(callback).Run();
    } else {
      OnError(std::move(error_callback), error_response);
    }
  }

  // Called when a descriptor value response for a method call is received.
  void OnReadValueResponse(ValueCallback callback,
                           ErrorCallback error_callback,
                           dbus::Response* response,
                           dbus::ErrorResponse* error_response) {
    if (!response) {
      OnError(std::move(error_callback), error_response);
      return;
    }

    dbus::MessageReader reader(response);
    base::span<const uint8_t> bytes;

    if (!reader.PopArrayOfBytes(&bytes)) {
      DVLOG(2) << "Error reading array of bytes in ValueCallback";
    }

    std::move(callback).Run(/*error_code=*/std::nullopt, base::ToVector(bytes));
  }

  // Called when a response for a failed method call is received.
  void OnError(ErrorCallback error_callback, dbus::ErrorResponse* response) {
    // Error response has optional error message argument.
    std::string error_name;
    std::string error_message;
    if (response) {
      dbus::MessageReader reader(response);
      error_name = response->GetErrorName();
      reader.PopString(&error_message);
    } else {
      error_name = kNoResponseError;
      error_message = "";
    }
    std::move(error_callback).Run(error_name, error_message);
  }

  raw_ptr<dbus::ObjectManager> object_manager_;

  // List of observers interested in event notifications from us.
  base::ObserverList<BluetoothGattDescriptorClient::Observer>::Unchecked
      observers_;

  // Weak pointer factory for generating 'this' pointers that might live longer
  // than we do.
  // Note: This should remain the last member so it'll be destroyed and
  // invalidate its weak pointers before any other members are destroyed.
  base::WeakPtrFactory<BluetoothGattDescriptorClientImpl> weak_ptr_factory_{
      this};
};

BluetoothGattDescriptorClient::BluetoothGattDescriptorClient() = default;

BluetoothGattDescriptorClient::~BluetoothGattDescriptorClient() = default;

// static
BluetoothGattDescriptorClient* BluetoothGattDescriptorClient::Create() {
  return new BluetoothGattDescriptorClientImpl();
}

}  // namespace bluez