/**
 * Copyright (c) 2010-2022 Contributors to the openHAB project
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 */
package org.openhab.binding.nanoleaf.internal.discovery;

import static org.openhab.binding.nanoleaf.internal.NanoleafBindingConstants.CONFIG_PANEL_ID;

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.eclipse.jdt.annotation.NonNullByDefault;
import org.eclipse.jdt.annotation.Nullable;
import org.openhab.binding.nanoleaf.internal.NanoleafBindingConstants;
import org.openhab.binding.nanoleaf.internal.NanoleafControllerListener;
import org.openhab.binding.nanoleaf.internal.NanoleafHandlerFactory;
import org.openhab.binding.nanoleaf.internal.handler.NanoleafControllerHandler;
import org.openhab.binding.nanoleaf.internal.model.ControllerInfo;
import org.openhab.binding.nanoleaf.internal.model.Layout;
import org.openhab.binding.nanoleaf.internal.model.PanelLayout;
import org.openhab.binding.nanoleaf.internal.model.PositionDatum;
import org.openhab.core.config.discovery.AbstractDiscoveryService;
import org.openhab.core.config.discovery.DiscoveryResult;
import org.openhab.core.config.discovery.DiscoveryResultBuilder;
import org.openhab.core.thing.ThingUID;
import org.openhab.core.thing.binding.BridgeHandler;
import org.openhab.core.thing.binding.ThingHandler;
import org.openhab.core.thing.binding.ThingHandlerService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The {@link NanoleafPanelsDiscoveryService} is responsible for discovering the individual
 * panels connected to the controller.
 *
 * @author Martin Raepple - Initial contribution
 * @author Kai Kreuzer - Made it a ThingHandlerService
 */
@NonNullByDefault
public class NanoleafPanelsDiscoveryService extends AbstractDiscoveryService
        implements NanoleafControllerListener, ThingHandlerService {

    private static final int SEARCH_TIMEOUT_SECONDS = 60;

    private final Logger logger = LoggerFactory.getLogger(NanoleafPanelsDiscoveryService.class);
    private @Nullable NanoleafControllerHandler bridgeHandler;
    private @Nullable ControllerInfo controllerInfo;

    /**
     * Constructs a new {@link NanoleafPanelsDiscoveryService}.
     */
    public NanoleafPanelsDiscoveryService() {
        super(NanoleafHandlerFactory.SUPPORTED_THING_TYPES_UIDS, SEARCH_TIMEOUT_SECONDS, false);
    }

    @Override
    public void deactivate() {
        NanoleafControllerHandler localBridgeHandler = bridgeHandler;
        if (localBridgeHandler != null) {
            Boolean result = localBridgeHandler.unregisterControllerListener(this);
            logger.debug("unregistration of controller was {}", result ? "successful" : "unsuccessful");
        }
        super.deactivate();
    }

    @Override
    protected void startScan() {
        logger.debug("Starting Nanoleaf panel discovery");
        createResultsFromControllerInfo();
    }

    /**
     * Called by the controller handler with bridge and panel data
     *
     * @param bridge The controller
     * @param controllerInfo Panel data (and more)
     */
    @Override
    public void onControllerInfoFetched(ThingUID bridge, ControllerInfo controllerInfo) {
        this.controllerInfo = controllerInfo;
    }

    private void createResultsFromControllerInfo() {
        ThingUID bridgeUID;
        BridgeHandler localBridgeHandler = bridgeHandler;
        if (localBridgeHandler != null) {
            bridgeUID = localBridgeHandler.getThing().getUID();
        } else {
            return;
        }

        ControllerInfo localControllerInfo = controllerInfo;
        if (localControllerInfo != null) {
            final PanelLayout panelLayout = localControllerInfo.getPanelLayout();
            @Nullable
            Layout layout = panelLayout.getLayout();

            if (layout != null && layout.getNumPanels() > 0) {
                @Nullable
                final List<PositionDatum> positionData = layout.getPositionData();
                if (positionData != null) {
                    Iterator<PositionDatum> iterator = positionData.iterator();
                    while (iterator.hasNext()) {
                        @Nullable
                        PositionDatum panel = iterator.next();
                        ThingUID newPanelThingUID = new ThingUID(NanoleafBindingConstants.THING_TYPE_LIGHT_PANEL,
                                bridgeUID, Integer.toString(panel.getPanelId()));

                        final Map<String, Object> properties = new HashMap<>(1);
                        properties.put(CONFIG_PANEL_ID, panel.getPanelId());

                        DiscoveryResult newPanel = DiscoveryResultBuilder.create(newPanelThingUID).withBridge(bridgeUID)
                                .withProperties(properties).withLabel("Light Panel " + panel.getPanelId())
                                .withRepresentationProperty(CONFIG_PANEL_ID).build();

                        logger.debug("Adding panel with id {} to inbox", panel.getPanelId());
                        thingDiscovered(newPanel);
                    }
                } else {
                    logger.debug("Couldn't add panels to inbox as layout position data was null");
                }

            } else {
                logger.debug("No panels found or connected to controller");
            }
        }
    }

    @Override
    public void setThingHandler(ThingHandler handler) {
        this.bridgeHandler = (NanoleafControllerHandler) handler;
        NanoleafControllerHandler localBridgeHandler = (NanoleafControllerHandler) handler;

        localBridgeHandler.registerControllerListener(this);
    }

    @Override
    public @Nullable ThingHandler getThingHandler() {
        return bridgeHandler;
    }
}
