/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.streampipes.sinks.databases.jvm.redis;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.commons.lang3.StringUtils;
import org.apache.streampipes.commons.exceptions.SpRuntimeException;
import org.apache.streampipes.model.runtime.Event;
import org.apache.streampipes.wrapper.context.EventSinkRuntimeContext;
import org.apache.streampipes.wrapper.runtime.EventSink;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.exceptions.JedisException;

public class Redis implements EventSink<RedisParameters> {

    private static final String EVENT_PREFIX = "sp:event:";
    private static final String EVENT_COUNT = "sp:events";
    private static JedisPool jedisPool = null;
    private String primaryKey;
    private Boolean autoIncrement;
    private String password;
    private String clientName;
    private Integer index;
    private Integer ttl;

    @Override
    public void onInvocation(RedisParameters parameters, EventSinkRuntimeContext runtimeContext) {
        if (jedisPool == null) initialPool(parameters);
        primaryKey = parameters.getPrimaryKey();
        autoIncrement = parameters.isAutoIncrement();
        password = parameters.getRedisPassword();
        clientName = parameters.getRedisClient();
        index = parameters.getRedisIndex();
        ttl = parameters.getTTL();
    }

    @Override
    public void onEvent(Event inputEvent) throws SpRuntimeException {
        try (Jedis jedis = getJedis()) {
            final String eventKey = getEventKey(inputEvent, autoIncrement ? jedis.incr(EVENT_COUNT) : 0L);
            jedis.set(eventKey, getEventValue(inputEvent));
            if (ttl > -1) jedis.expire(eventKey, ttl);
        } catch (SpRuntimeException e) {
            throw e;
        } catch (Exception ex) {
            throw new SpRuntimeException("Could not persist event to redis", ex);
        }
    }

    @Override
    public void onDetach() {
        if (jedisPool != null && !jedisPool.isClosed()) jedisPool.close();
        jedisPool = null;
    }

    private void initialPool(RedisParameters parameters) {
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMaxTotal(parameters.getRedisPoolMaxActive());
        config.setMaxIdle(parameters.getRedisPoolMaxIdle());
        config.setMaxWaitMillis(parameters.getRedisPoolMaxWait());
        config.setTestWhileIdle(false);
        config.setTestOnBorrow(false);
        config.setTestOnReturn(false);
        jedisPool = new JedisPool(config, parameters.getRedisHost(),
                parameters.getRedisPort(), parameters.getRedisPoolTimeout());
    }

    private Jedis getJedis() throws SpRuntimeException {
        Jedis jedis = jedisPool.getResource();
        try {
            jedis.connect();
            if (StringUtils.isNotBlank(password)) jedis.auth(password);
            if (StringUtils.isNotBlank(clientName)) jedis.clientSetname(clientName);
            if (index > -1) jedis.select(index);
        } catch (JedisException e) {
            jedis.close();
            throw new SpRuntimeException("Could not connect to redis", e);
        }
        return jedis;
    }

    private String getEventKey(Event event, Long count) {
        if (autoIncrement) {
            return EVENT_PREFIX + count;
        } else {
            String value = event.getFieldBySelector(primaryKey).getAsPrimitive().getAsString();
            return EVENT_PREFIX + value;
        }
    }

    private String getEventValue(Event event) throws SpRuntimeException {
        try {
            return new ObjectMapper().writeValueAsString(event.getRaw());
        } catch (JsonProcessingException e) {
            throw new SpRuntimeException("Could not convert event to JSON", e);
        }
    }

}
