// SPDX-FileCopyrightText: 2024 Joshua Goins <josh@redstrate.com>
// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL

#include "deskcontrol.h"

#include <KLocalizedString>
#include <QBluetoothLocalDevice>

const auto DESK_UUID_KEY = QStringLiteral("DeskUUID");

const auto ADV_SVC = QBluetoothUuid("99fa0001-338a-1024-8a49-009c0215f78a");

const auto COMMAND_CHARACTERISTIC = QBluetoothUuid("99fa0002-338a-1024-8a49-009c0215f78a");
const auto POSITION_CHARACTERISTIC = QBluetoothUuid("99fa0021-338a-1024-8a49-009c0215f78a");

const auto upCommand = QByteArray::fromHex("4700");
const auto downCommand = QByteArray::fromHex("4600");

constexpr auto MAX_HEIGHT = 1.27;
constexpr auto MIN_HEIGHT = 0.62;

DeskControl::DeskControl(QObject *parent, const KPluginMetaData &data, const QVariantList &args)
    : Applet(parent, data, args) {
    m_localDevice.powerOn();
    // If we have connected to the desk previously, connect. Otherwise discover one.
    if (config().hasKey(DESK_UUID_KEY)) {
        connectToDesk();
    } else {
        searchForDesk();
    }
}

DeskControl::~DeskControl() = default;

DeskControl::DeskState DeskControl::state() const {
    return DeskState::NotFound;
}

void DeskControl::up() const {
    Q_ASSERT(m_commandService);
    Q_ASSERT(m_commandCharacteristic.isValid());

    m_commandService->writeCharacteristic(m_commandCharacteristic, upCommand);
}

void DeskControl::down() const {
    Q_ASSERT(m_commandService);
    Q_ASSERT(m_commandCharacteristic.isValid());

    m_commandService->writeCharacteristic(m_commandCharacteristic, downCommand);
}

void DeskControl::connectToDesk() {
    const auto lastDeskUUID = config().readEntry(DESK_UUID_KEY);
    qInfo() << "Connecting to desk:" << lastDeskUUID;

    m_controller = QLowEnergyController::createCentral(QBluetoothDeviceInfo(QBluetoothAddress(lastDeskUUID), QStringLiteral("Desk"), 0));

    connect(m_controller, &QLowEnergyController::connected, this, [this]() {
        m_controller->discoverServices();
    });
    connect(m_controller, &QLowEnergyController::discoveryFinished, this, [this]() {
        for (auto service: m_controller->services()) {
            if (service.toString() == QStringLiteral("{99fa0001-338a-1024-8a49-009c0215f78a}")) {
                m_commandService = m_controller->createServiceObject(service);
                m_commandService->discoverDetails();

                connect(m_commandService, &QLowEnergyService::stateChanged, this, [this](QLowEnergyService::ServiceState state) {
                    m_commandCharacteristic = m_commandService->characteristic(COMMAND_CHARACTERISTIC);
                });
                connect(m_commandService, &QLowEnergyService::errorOccurred, [](QLowEnergyService::ServiceError error) {
                    qWarning() << error;
                });
            }
            if (service.toString() == QStringLiteral("{99fa0020-338a-1024-8a49-009c0215f78a}")) {
                m_positionCommandService = m_controller->createServiceObject(service);
                m_positionCommandService->discoverDetails();

                connect(m_positionCommandService, &QLowEnergyService::errorOccurred, [](QLowEnergyService::ServiceError error) {
                    qWarning() << error;
                });
                connect(m_positionCommandService, &QLowEnergyService::stateChanged, this, [this](QLowEnergyService::ServiceState state) {
                    QLowEnergyCharacteristic batteryLevel = m_positionCommandService->characteristic(POSITION_CHARACTERISTIC);
                    if (!batteryLevel.isValid())
                        return;

                    QLowEnergyDescriptor notification = batteryLevel.descriptor(
                            QBluetoothUuid::DescriptorType::ClientCharacteristicConfiguration);
                    if (!notification.isValid())
                        return;

                    m_positionCommandService->writeDescriptor(notification, QByteArray::fromHex("0100"));
                });

                connect(m_positionCommandService, &QLowEnergyService::characteristicChanged, this, [this](const QLowEnergyCharacteristic &info, const QByteArray &value) {
                    const int32_t highByte = value.at(1);
                    const int32_t lowByte = value.at(0);
                    const int32_t number = (highByte << 8) + lowByte;

                    m_height = (static_cast<float>(number) / 1000.0) + MIN_HEIGHT;
                    Q_EMIT heightChanged();
                });
            }
        }
    });

    m_controller->connectToDevice();
}

void DeskControl::searchForDesk() {
    qInfo() << "Searching for desk...";

    QList<QBluetoothAddress> remotes = m_localDevice.connectedDevices();
    if (remotes.empty()) {
        return;
    }

    for (const auto &address : remotes) {
        auto controller = QLowEnergyController::createCentral(QBluetoothDeviceInfo(address, QStringLiteral("Desk"), 0));

        qInfo() << controller->services();

        connect(controller, &QLowEnergyController::connected, this, [this, controller]() {
            controller->discoverServices();
        });
        connect(controller, &QLowEnergyController::discoveryFinished, this, [this, controller, address]() {
            controller->deleteLater();

            for (auto service: controller->services()) {
                if (service == ADV_SVC) {
                    qInfo() << "Found desk:" << DESK_UUID_KEY;
                    config().writeEntry(DESK_UUID_KEY, address.toString());
                    connectToDesk();
                    break;
                }
            }
        });

        controller->connectToDevice();
    }
}

K_PLUGIN_CLASS(DeskControl)

#include "deskcontrol.moc"
#include "moc_deskcontrol.cpp"