/**
 * Copyright © 2016-2018 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.rule.engine.action;

import com.datastax.driver.core.utils.UUIDs;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import lombok.extern.slf4j.Slf4j;
import org.thingsboard.rule.engine.api.*;
import org.thingsboard.rule.engine.api.util.TbNodeUtils;
import org.thingsboard.server.common.data.plugin.ComponentType;
import org.thingsboard.server.common.msg.TbMsg;
import org.thingsboard.server.common.msg.TbMsgDataType;
import org.thingsboard.server.common.msg.TbMsgMetaData;
import org.thingsboard.server.common.msg.session.SessionMsgType;

import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

import static org.thingsboard.rule.engine.api.TbRelationTypes.SUCCESS;

@Slf4j
@RuleNode(
        type = ComponentType.ACTION,
        name = "message count",
        configClazz = TbMsgCountNodeConfiguration.class,
        nodeDescription = "Count incoming messages",
        nodeDetails = "Count incoming messages for specified interval and produces POST_TELEMETRY_REQUEST msg with messages count",
        icon = "functions",
        uiResources = {"static/rulenode/rulenode-core-config.js"},
        configDirective = "tbActionNodeMsgCountConfig"
)
public class TbMsgCountNode implements TbNode {

    private static final String TB_MSG_COUNT_NODE_MSG = "TbMsgCountNodeMsg";

    private AtomicLong messagesProcessed = new AtomicLong(0);
    private final Gson gson = new Gson();
    private UUID nextTickId;
    private long delay;
    private String telemetryPrefix;
    private long lastScheduledTs;

    @Override
    public void init(TbContext ctx, TbNodeConfiguration configuration) throws TbNodeException {
        TbMsgCountNodeConfiguration config = TbNodeUtils.convert(configuration, TbMsgCountNodeConfiguration.class);
        this.delay = TimeUnit.SECONDS.toMillis(config.getInterval());
        this.telemetryPrefix = config.getTelemetryPrefix();
        scheduleTickMsg(ctx);

    }

    @Override
    public void onMsg(TbContext ctx, TbMsg msg) {
        if (msg.getType().equals(TB_MSG_COUNT_NODE_MSG) && msg.getId().equals(nextTickId)) {
            JsonObject telemetryJson = new JsonObject();
            telemetryJson.addProperty(this.telemetryPrefix + "_" + ctx.getNodeId(), messagesProcessed.longValue());

            messagesProcessed = new AtomicLong(0);

            TbMsgMetaData metaData = new TbMsgMetaData();
            metaData.putValue("delta", Long.toString(System.currentTimeMillis() - lastScheduledTs + delay));

            TbMsg tbMsg = new TbMsg(UUIDs.timeBased(), SessionMsgType.POST_TELEMETRY_REQUEST.name(), ctx.getTenantId(), metaData, TbMsgDataType.JSON, gson.toJson(telemetryJson), null, null, 0L);
            ctx.tellNext(tbMsg, SUCCESS);
            scheduleTickMsg(ctx);
        } else {
            messagesProcessed.incrementAndGet();
        }
    }

    private void scheduleTickMsg(TbContext ctx) {
        long curTs = System.currentTimeMillis();
        if (lastScheduledTs == 0L) {
            lastScheduledTs = curTs;
        }
        lastScheduledTs = lastScheduledTs + delay;
        long curDelay = Math.max(0L, (lastScheduledTs - curTs));
        TbMsg tickMsg = ctx.newMsg(TB_MSG_COUNT_NODE_MSG, ctx.getSelfId(), new TbMsgMetaData(), "");
        nextTickId = tickMsg.getId();
        ctx.tellSelf(tickMsg, curDelay);
    }

    @Override
    public void destroy() {
    }
}