/**
 * Copyright © 2016-2017 The Thingsboard Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.thingsboard.server.dao.device;

import com.google.common.base.Function;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.RandomStringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;
import org.thingsboard.server.common.data.Device;
import org.thingsboard.server.common.data.id.CustomerId;
import org.thingsboard.server.common.data.id.DeviceId;
import org.thingsboard.server.common.data.id.TenantId;
import org.thingsboard.server.common.data.page.TextPageData;
import org.thingsboard.server.common.data.page.TextPageLink;
import org.thingsboard.server.common.data.security.DeviceCredentials;
import org.thingsboard.server.common.data.security.DeviceCredentialsType;
import org.thingsboard.server.dao.customer.CustomerDao;
import org.thingsboard.server.dao.exception.DataValidationException;
import org.thingsboard.server.dao.model.CustomerEntity;
import org.thingsboard.server.dao.model.DeviceEntity;
import org.thingsboard.server.dao.model.TenantEntity;
import org.thingsboard.server.dao.service.DataValidator;
import org.thingsboard.server.dao.service.PaginatedRemover;
import org.thingsboard.server.dao.tenant.TenantDao;

import java.util.List;
import java.util.Optional;

import static org.thingsboard.server.dao.DaoUtil.convertDataList;
import static org.thingsboard.server.dao.DaoUtil.getData;
import static org.thingsboard.server.dao.model.ModelConstants.NULL_UUID;
import static org.thingsboard.server.dao.service.Validator.validateId;
import static org.thingsboard.server.dao.service.Validator.validatePageLink;

@Service
@Slf4j
public class DeviceServiceImpl implements DeviceService {

    @Autowired
    private DeviceDao deviceDao;

    @Autowired
    private TenantDao tenantDao;

    @Autowired
    private CustomerDao customerDao;

    @Autowired
    private DeviceCredentialsService deviceCredentialsService;

    @Override
    public Device findDeviceById(DeviceId deviceId) {
        log.trace("Executing findDeviceById [{}]", deviceId);
        validateId(deviceId, "Incorrect deviceId " + deviceId);
        DeviceEntity deviceEntity = deviceDao.findById(deviceId.getId());
        return getData(deviceEntity);
    }

    @Override
    public ListenableFuture<Device> findDeviceByIdAsync(DeviceId deviceId) {
        log.trace("Executing findDeviceById [{}]", deviceId);
        validateId(deviceId, "Incorrect deviceId " + deviceId);
        ListenableFuture<DeviceEntity> deviceEntity = deviceDao.findByIdAsync(deviceId.getId());
        return Futures.transform(deviceEntity, (Function<? super DeviceEntity, ? extends Device>) input -> getData(input));
    }

    @Override
    public Optional<Device> findDeviceByTenantIdAndName(TenantId tenantId, String name) {
        log.trace("Executing findDeviceByTenantIdAndName [{}][{}]", tenantId, name);
        validateId(tenantId, "Incorrect tenantId " + tenantId);
        Optional<DeviceEntity> deviceEntityOpt = deviceDao.findDevicesByTenantIdAndName(tenantId.getId(), name);
        if (deviceEntityOpt.isPresent()) {
            return Optional.of(getData(deviceEntityOpt.get()));
        } else {
            return Optional.empty();
        }
    }

    @Override
    public Device saveDevice(Device device) {
        log.trace("Executing saveDevice [{}]", device);
        deviceValidator.validate(device);
        DeviceEntity deviceEntity = deviceDao.save(device);
        if (device.getId() == null) {
            DeviceCredentials deviceCredentials = new DeviceCredentials();
            deviceCredentials.setDeviceId(new DeviceId(deviceEntity.getId()));
            deviceCredentials.setCredentialsType(DeviceCredentialsType.ACCESS_TOKEN);
            deviceCredentials.setCredentialsId(RandomStringUtils.randomAlphanumeric(20));
            deviceCredentialsService.createDeviceCredentials(deviceCredentials);
        }
        return getData(deviceEntity);
    }

    @Override
    public Device assignDeviceToCustomer(DeviceId deviceId, CustomerId customerId) {
        Device device = findDeviceById(deviceId);
        device.setCustomerId(customerId);
        return saveDevice(device);
    }

    @Override
    public Device unassignDeviceFromCustomer(DeviceId deviceId) {
        Device device = findDeviceById(deviceId);
        device.setCustomerId(null);
        return saveDevice(device);
    }

    @Override
    public void deleteDevice(DeviceId deviceId) {
        log.trace("Executing deleteDevice [{}]", deviceId);
        validateId(deviceId, "Incorrect deviceId " + deviceId);
        DeviceCredentials deviceCredentials = deviceCredentialsService.findDeviceCredentialsByDeviceId(deviceId);
        if (deviceCredentials != null) {
            deviceCredentialsService.deleteDeviceCredentials(deviceCredentials);
        }
        deviceDao.removeById(deviceId.getId());
    }

    @Override
    public TextPageData<Device> findDevicesByTenantId(TenantId tenantId, TextPageLink pageLink) {
        log.trace("Executing findDevicesByTenantId, tenantId [{}], pageLink [{}]", tenantId, pageLink);
        validateId(tenantId, "Incorrect tenantId " + tenantId);
        validatePageLink(pageLink, "Incorrect page link " + pageLink);
        List<DeviceEntity> deviceEntities = deviceDao.findDevicesByTenantId(tenantId.getId(), pageLink);
        List<Device> devices = convertDataList(deviceEntities);
        return new TextPageData<Device>(devices, pageLink);
    }

    @Override
    public void deleteDevicesByTenantId(TenantId tenantId) {
        log.trace("Executing deleteDevicesByTenantId, tenantId [{}]", tenantId);
        validateId(tenantId, "Incorrect tenantId " + tenantId);
        tenantDevicesRemover.removeEntitites(tenantId);
    }

    @Override
    public TextPageData<Device> findDevicesByTenantIdAndCustomerId(TenantId tenantId, CustomerId customerId, TextPageLink pageLink) {
        log.trace("Executing findDevicesByTenantIdAndCustomerId, tenantId [{}], customerId [{}], pageLink [{}]", tenantId, customerId, pageLink);
        validateId(tenantId, "Incorrect tenantId " + tenantId);
        validateId(customerId, "Incorrect customerId " + customerId);
        validatePageLink(pageLink, "Incorrect page link " + pageLink);
        List<DeviceEntity> deviceEntities = deviceDao.findDevicesByTenantIdAndCustomerId(tenantId.getId(), customerId.getId(), pageLink);
        List<Device> devices = convertDataList(deviceEntities);
        return new TextPageData<Device>(devices, pageLink);
    }

    @Override
    public void unassignCustomerDevices(TenantId tenantId, CustomerId customerId) {
        log.trace("Executing unassignCustomerDevices, tenantId [{}], customerId [{}]", tenantId, customerId);
        validateId(tenantId, "Incorrect tenantId " + tenantId);
        validateId(customerId, "Incorrect customerId " + customerId);
        new CustomerDevicesUnassigner(tenantId).removeEntitites(customerId);
    }

    private DataValidator<Device> deviceValidator =
            new DataValidator<Device>() {

                @Override
                protected void validateCreate(Device device) {
                    deviceDao.findDevicesByTenantIdAndName(device.getTenantId().getId(), device.getName()).ifPresent(
                            d -> {
                                throw new DataValidationException("Device with such name already exists!");
                            }
                    );
                }

                @Override
                protected void validateUpdate(Device device) {
                    deviceDao.findDevicesByTenantIdAndName(device.getTenantId().getId(), device.getName()).ifPresent(
                            d -> {
                                if (!d.getId().equals(device.getUuidId())) {
                                    throw new DataValidationException("Device with such name already exists!");
                                }
                            }
                    );
                }

                @Override
                protected void validateDataImpl(Device device) {
                    if (StringUtils.isEmpty(device.getName())) {
                        throw new DataValidationException("Device name should be specified!");
                    }
                    if (device.getTenantId() == null) {
                        throw new DataValidationException("Device should be assigned to tenant!");
                    } else {
                        TenantEntity tenant = tenantDao.findById(device.getTenantId().getId());
                        if (tenant == null) {
                            throw new DataValidationException("Device is referencing to non-existent tenant!");
                        }
                    }
                    if (device.getCustomerId() == null) {
                        device.setCustomerId(new CustomerId(NULL_UUID));
                    } else if (!device.getCustomerId().getId().equals(NULL_UUID)) {
                        CustomerEntity customer = customerDao.findById(device.getCustomerId().getId());
                        if (customer == null) {
                            throw new DataValidationException("Can't assign device to non-existent customer!");
                        }
                        if (!customer.getTenantId().equals(device.getTenantId().getId())) {
                            throw new DataValidationException("Can't assign device to customer from different tenant!");
                        }
                    }
                }
            };

    private PaginatedRemover<TenantId, DeviceEntity> tenantDevicesRemover =
            new PaginatedRemover<TenantId, DeviceEntity>() {

                @Override
                protected List<DeviceEntity> findEntities(TenantId id, TextPageLink pageLink) {
                    return deviceDao.findDevicesByTenantId(id.getId(), pageLink);
                }

                @Override
                protected void removeEntity(DeviceEntity entity) {
                    deleteDevice(new DeviceId(entity.getId()));
                }
            };

    class CustomerDevicesUnassigner extends PaginatedRemover<CustomerId, DeviceEntity> {

        private TenantId tenantId;

        CustomerDevicesUnassigner(TenantId tenantId) {
            this.tenantId = tenantId;
        }

        @Override
        protected List<DeviceEntity> findEntities(CustomerId id, TextPageLink pageLink) {
            return deviceDao.findDevicesByTenantIdAndCustomerId(tenantId.getId(), id.getId(), pageLink);
        }

        @Override
        protected void removeEntity(DeviceEntity entity) {
            unassignDeviceFromCustomer(new DeviceId(entity.getId()));
        }

    }
}
