/**
 * 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.actors.plugin;

import java.io.IOException;
import java.util.*;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.stream.Collectors;

import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.ResultSetFuture;
import com.datastax.driver.core.Row;
import com.google.common.base.Function;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import lombok.extern.slf4j.Slf4j;
import org.thingsboard.server.common.data.DataConstants;
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.PluginId;
import org.thingsboard.server.common.data.id.TenantId;
import org.thingsboard.server.common.data.kv.AttributeKey;
import org.thingsboard.server.common.data.kv.AttributeKvEntry;
import org.thingsboard.server.common.data.kv.TsKvEntry;
import org.thingsboard.server.common.data.kv.TsKvQuery;
import org.thingsboard.server.common.data.page.TextPageData;
import org.thingsboard.server.common.data.page.TextPageLink;
import org.thingsboard.server.common.msg.cluster.ServerAddress;
import org.thingsboard.server.extensions.api.device.DeviceAttributesEventNotificationMsg;
import org.thingsboard.server.extensions.api.plugins.PluginApiCallSecurityContext;
import org.thingsboard.server.extensions.api.plugins.PluginContext;
import org.thingsboard.server.extensions.api.plugins.PluginCallback;
import org.thingsboard.server.extensions.api.plugins.msg.PluginToRuleMsg;
import org.thingsboard.server.extensions.api.plugins.msg.TimeoutMsg;
import org.thingsboard.server.extensions.api.plugins.msg.ToDeviceRpcRequest;
import org.thingsboard.server.extensions.api.plugins.rpc.PluginRpcMsg;
import org.thingsboard.server.extensions.api.plugins.rpc.RpcMsg;
import org.thingsboard.server.extensions.api.plugins.ws.PluginWebsocketSessionRef;
import org.thingsboard.server.extensions.api.plugins.ws.msg.PluginWebsocketMsg;

import akka.actor.ActorRef;
import org.w3c.dom.Attr;

import javax.annotation.Nullable;

@Slf4j
public final class PluginProcessingContext implements PluginContext {

    private static final Executor executor = Executors.newSingleThreadExecutor();

    private final SharedPluginProcessingContext pluginCtx;
    private final Optional<PluginApiCallSecurityContext> securityCtx;

    public PluginProcessingContext(SharedPluginProcessingContext pluginCtx, PluginApiCallSecurityContext securityCtx) {
        super();
        this.pluginCtx = pluginCtx;
        this.securityCtx = Optional.ofNullable(securityCtx);
    }

    @Override
    public void sendPluginRpcMsg(RpcMsg msg) {
        this.pluginCtx.rpcService.tell(new PluginRpcMsg(pluginCtx.tenantId, pluginCtx.pluginId, msg));
    }

    @Override
    public void send(PluginWebsocketMsg<?> wsMsg) throws IOException {
        pluginCtx.msgEndpoint.send(wsMsg);
    }

    @Override
    public void close(PluginWebsocketSessionRef sessionRef) throws IOException {
        pluginCtx.msgEndpoint.close(sessionRef);
    }

    @Override
    public void saveAttributes(final TenantId tenantId, final DeviceId deviceId, final String scope, final List<AttributeKvEntry> attributes, final PluginCallback<Void> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<ResultSet>> rsListFuture = pluginCtx.attributesService.save(deviceId, scope, attributes);
            Futures.addCallback(rsListFuture, getListCallback(callback, v -> {
                onDeviceAttributesChanged(tenantId, deviceId, scope, attributes);
                return null;
            }), executor);
        }));
    }

    @Override
    public void removeAttributes(final TenantId tenantId, final DeviceId deviceId, final String scope, final List<String> keys, final PluginCallback<Void> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<ResultSet>> future = pluginCtx.attributesService.removeAll(deviceId, scope, keys);
            Futures.addCallback(future, getCallback(callback, v -> null), executor);
            onDeviceAttributesDeleted(tenantId, deviceId, keys.stream().map(key -> new AttributeKey(scope, key)).collect(Collectors.toSet()));
        }));
    }

    @Override
    public void loadAttribute(DeviceId deviceId, String attributeType, String attributeKey, final PluginCallback<Optional<AttributeKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<Optional<AttributeKvEntry>> future = pluginCtx.attributesService.find(deviceId, attributeType, attributeKey);
            Futures.addCallback(future, getCallback(callback, v -> v), executor);
        }));
    }

    @Override
    public void loadAttributes(DeviceId deviceId, String attributeType, Collection<String> attributeKeys, final PluginCallback<List<AttributeKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<AttributeKvEntry>> future = pluginCtx.attributesService.find(deviceId, attributeType, attributeKeys);
            Futures.addCallback(future, getCallback(callback, v -> v), executor);
        }));
    }

    @Override
    public void loadAttributes(DeviceId deviceId, String attributeType, PluginCallback<List<AttributeKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<AttributeKvEntry>> future = pluginCtx.attributesService.findAll(deviceId, attributeType);
            Futures.addCallback(future, getCallback(callback, v -> v), executor);
        }));
    }

    @Override
    public void loadAttributes(final DeviceId deviceId, final Collection<String> attributeTypes, final PluginCallback<List<AttributeKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            List<ListenableFuture<List<AttributeKvEntry>>> futures = new ArrayList<>();
            attributeTypes.forEach(attributeType -> futures.add(pluginCtx.attributesService.findAll(deviceId, attributeType)));
            convertFuturesAndAddCallback(callback, futures);
        }));
    }

    @Override
    public void loadAttributes(final DeviceId deviceId, final Collection<String> attributeTypes, final Collection<String> attributeKeys, final PluginCallback<List<AttributeKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            List<ListenableFuture<List<AttributeKvEntry>>> futures = new ArrayList<>();
            attributeTypes.forEach(attributeType -> futures.add(pluginCtx.attributesService.find(deviceId, attributeType, attributeKeys)));
            convertFuturesAndAddCallback(callback, futures);
        }));
    }

    @Override
    public void saveTsData(final DeviceId deviceId, final TsKvEntry entry, final PluginCallback<Void> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<ResultSet>> rsListFuture = pluginCtx.tsService.save(DataConstants.DEVICE, deviceId, entry);
            Futures.addCallback(rsListFuture, getListCallback(callback, v -> null), executor);
        }));
    }

    @Override
    public void saveTsData(final DeviceId deviceId, final List<TsKvEntry> entries, final PluginCallback<Void> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<ResultSet>> rsListFuture = pluginCtx.tsService.save(DataConstants.DEVICE, deviceId, entries);
            Futures.addCallback(rsListFuture, getListCallback(callback, v -> null), executor);
        }));
    }

    @Override
    public void loadTimeseries(final DeviceId deviceId, final List<TsKvQuery> queries, final PluginCallback<List<TsKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<TsKvEntry>> future = pluginCtx.tsService.findAll(DataConstants.DEVICE, deviceId, queries);
            Futures.addCallback(future, getCallback(callback, v -> v), executor);
        }));
    }

    @Override
    public void loadLatestTimeseries(final DeviceId deviceId, final PluginCallback<List<TsKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ResultSetFuture future = pluginCtx.tsService.findAllLatest(DataConstants.DEVICE, deviceId);
            Futures.addCallback(future, getCallback(callback, pluginCtx.tsService::convertResultSetToTsKvEntryList), executor);
        }));
    }

    @Override
    public void loadLatestTimeseries(final DeviceId deviceId, final Collection<String> keys, final PluginCallback<List<TsKvEntry>> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> {
            ListenableFuture<List<ResultSet>> rsListFuture = pluginCtx.tsService.findLatest(DataConstants.DEVICE, deviceId, keys);
            Futures.addCallback(rsListFuture, getListCallback(callback, rsList ->
            {
                List<TsKvEntry> result = new ArrayList<>();
                for (ResultSet rs : rsList) {
                    Row row = rs.one();
                    if (row != null) {
                        result.add(pluginCtx.tsService.convertResultToTsKvEntry(row));
                    }
                }
                return result;
            }), executor);
        }));
    }

    @Override
    public void reply(PluginToRuleMsg<?> msg) {
        pluginCtx.parentActor.tell(msg, ActorRef.noSender());
    }

    @Override
    public PluginId getPluginId() {
        return pluginCtx.pluginId;
    }

    @Override
    public Optional<PluginApiCallSecurityContext> getSecurityCtx() {
        return securityCtx;
    }

    private void onDeviceAttributesDeleted(TenantId tenantId, DeviceId deviceId, Set<AttributeKey> keys) {
        pluginCtx.toDeviceActor(DeviceAttributesEventNotificationMsg.onDelete(tenantId, deviceId, keys));
    }

    private void onDeviceAttributesChanged(TenantId tenantId, DeviceId deviceId, String scope, List<AttributeKvEntry> values) {
        pluginCtx.toDeviceActor(DeviceAttributesEventNotificationMsg.onUpdate(tenantId, deviceId, scope, values));
    }

    private <T> FutureCallback<List<ResultSet>> getListCallback(final PluginCallback<T> callback, Function<List<ResultSet>, T> transformer) {
        return new FutureCallback<List<ResultSet>>() {
            @Override
            public void onSuccess(@Nullable List<ResultSet> result) {
                pluginCtx.self().tell(PluginCallbackMessage.onSuccess(callback, transformer.apply(result)), ActorRef.noSender());
            }

            @Override
            public void onFailure(Throwable t) {
                if (t instanceof Exception) {
                    pluginCtx.self().tell(PluginCallbackMessage.onError(callback, (Exception) t), ActorRef.noSender());
                } else {
                    log.error("Critical error: {}", t.getMessage(), t);
                }
            }
        };
    }

    private <T, R> FutureCallback<R> getCallback(final PluginCallback<T> callback, Function<R, T> transformer) {
        return new FutureCallback<R>() {
            @Override
            public void onSuccess(@Nullable R result) {
                try {
                    pluginCtx.self().tell(PluginCallbackMessage.onSuccess(callback, transformer.apply(result)), ActorRef.noSender());
                } catch (Exception e) {
                    pluginCtx.self().tell(PluginCallbackMessage.onError(callback, e), ActorRef.noSender());
                }
            }

            @Override
            public void onFailure(Throwable t) {
                if (t instanceof Exception) {
                    pluginCtx.self().tell(PluginCallbackMessage.onError(callback, (Exception) t), ActorRef.noSender());
                } else {
                    log.error("Critical error: {}", t.getMessage(), t);
                }
            }
        };
    }

    @Override
    public void checkAccess(DeviceId deviceId, PluginCallback<Void> callback) {
        validate(deviceId, new ValidationCallback(callback, ctx -> callback.onSuccess(ctx, null)));
    }

    private void validate(DeviceId deviceId, ValidationCallback callback) {
        if (securityCtx.isPresent()) {
            final PluginApiCallSecurityContext ctx = securityCtx.get();
            if (ctx.isTenantAdmin() || ctx.isCustomerUser()) {
                ListenableFuture<Device> deviceFuture = pluginCtx.deviceService.findDeviceByIdAsync(deviceId);
                Futures.addCallback(deviceFuture, getCallback(callback, device -> {
                    if (device == null) {
                        return Boolean.FALSE;
                    } else {
                        if (!device.getTenantId().equals(ctx.getTenantId())) {
                            return Boolean.FALSE;
                        } else if (ctx.isCustomerUser() && !device.getCustomerId().equals(ctx.getCustomerId())) {
                            return Boolean.FALSE;
                        } else {
                            return Boolean.TRUE;
                        }
                    }
                }));
            } else {
                callback.onSuccess(this, Boolean.FALSE);
            }
        } else {
            callback.onSuccess(this, Boolean.TRUE);
        }
    }

    @Override
    public Optional<ServerAddress> resolve(DeviceId deviceId) {
        return pluginCtx.routingService.resolve(deviceId);
    }

    @Override
    public void getDevice(DeviceId deviceId, PluginCallback<Device> callback) {
        //TODO: add caching here with async api.
        Device device = pluginCtx.deviceService.findDeviceById(deviceId);
        pluginCtx.self().tell(PluginCallbackMessage.onSuccess(callback, device), ActorRef.noSender());
    }

    @Override
    public void getCustomerDevices(TenantId tenantId, CustomerId customerId, int limit, PluginCallback<List<Device>> callback) {
        //TODO: add caching here with async api.
        List<Device> devices = pluginCtx.deviceService.findDevicesByTenantIdAndCustomerId(tenantId, customerId, new TextPageLink(limit)).getData();
        pluginCtx.self().tell(PluginCallbackMessage.onSuccess(callback, devices), ActorRef.noSender());
    }

    @Override
    public void sendRpcRequest(ToDeviceRpcRequest msg) {
        pluginCtx.sendRpcRequest(msg);
    }

    @Override
    public void scheduleTimeoutMsg(TimeoutMsg msg) {
        pluginCtx.scheduleTimeoutMsg(msg);
    }


    private void convertFuturesAndAddCallback(PluginCallback<List<AttributeKvEntry>> callback, List<ListenableFuture<List<AttributeKvEntry>>> futures) {
        ListenableFuture<List<AttributeKvEntry>> future = Futures.transform(Futures.successfulAsList(futures),
                (Function<? super List<List<AttributeKvEntry>>, ? extends List<AttributeKvEntry>>) input -> {
                    List<AttributeKvEntry> result = new ArrayList<>();
                    input.forEach(r -> result.addAll(r));
                    return result;
                }, executor);
        Futures.addCallback(future, getCallback(callback, v -> v), executor);
    }
}
