/*
 * Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. 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.wso2.carbon.stream.processor.core.internal;


import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wso2.carbon.stream.processor.core.internal.exception.ExecutionPlanConfigurationException;
import org.wso2.carbon.stream.processor.core.internal.util.EventProcessorConstants;
import org.wso2.carbon.stream.processor.core.internal.util.ExecutionPlanFilesystemInvoker;
import org.wso2.siddhi.core.ExecutionPlanRuntime;
import org.wso2.siddhi.core.SiddhiManager;
import org.wso2.siddhi.core.stream.input.InputHandler;
import org.wso2.siddhi.query.api.ExecutionPlan;
import org.wso2.siddhi.query.api.annotation.Element;
import org.wso2.siddhi.query.api.exception.ExecutionPlanValidationException;
import org.wso2.siddhi.query.api.util.AnnotationHelper;
import org.wso2.siddhi.query.compiler.SiddhiCompiler;

import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;


/**
 * Class which manage execution plans
 */
public class StreamProcessorService {

    private Map<String, ExecutionPlanRuntime> executionPlanRunTimeMap = new ConcurrentHashMap<>();
    private Map<String, Map<String, InputHandler>> executionPlanSpecificInputHandlerMap = new ConcurrentHashMap<>();
    private Map<String, ExecutionPlanConfiguration> executionPlanConfigurationMap = new ConcurrentHashMap<>();
    private Map<String, String> executionPlanFileMap = new ConcurrentHashMap<>();
    private static final Logger log = LoggerFactory.getLogger(StreamProcessorService.class);

    public void deployExecutionPlan(String executionPlan, String executionPlanFileName) {
        ExecutionPlan parsedExecutionPlan = SiddhiCompiler.parse(executionPlan);
        Element nameAnnotation = AnnotationHelper.getAnnotationElement(EventProcessorConstants.ANNOTATION_NAME_NAME,
                null, parsedExecutionPlan.getAnnotations());

        if (nameAnnotation == null || nameAnnotation.getValue().isEmpty()) {
            throw new ExecutionPlanValidationException("Execution plan name must be provided as @Plan:name('name').");
        }
        String executionPlanName = nameAnnotation.getValue();

        if (!executionPlanRunTimeMap.containsKey(executionPlanName)) {
            SiddhiManager siddhiManager = StreamProcessorDataHolder.getSiddhiManager();
            ExecutionPlanConfiguration executionPlanConfiguration = new ExecutionPlanConfiguration();
            executionPlanConfiguration.setName(executionPlanName);
            executionPlanConfiguration.setExecutionPlan(executionPlan);
            executionPlanConfigurationMap.put(executionPlanName, executionPlanConfiguration);
            ExecutionPlanRuntime executionPlanRuntime = siddhiManager.createExecutionPlanRuntime(executionPlan);

            if (executionPlanRuntime != null) {
                Set<String> streamNames = executionPlanRuntime.getStreamDefinitionMap().keySet();
                Map<String, InputHandler> inputHandlerMap =
                        new ConcurrentHashMap<String, InputHandler>(streamNames.size());
                for (String streamName : streamNames) {
                    inputHandlerMap.put(streamName, executionPlanRuntime.getInputHandler(streamName));
                }

                executionPlanSpecificInputHandlerMap.put(executionPlanName, inputHandlerMap);
                executionPlanRunTimeMap.put(executionPlanName, executionPlanRuntime);
                if (executionPlanFileName != null) {
                    executionPlanFileMap.put(executionPlanFileName, executionPlanName);
                } else {
                    executionPlanFileMap.put(executionPlanName, executionPlanName);
                }

                executionPlanRuntime.start();
                log.info("Execution plan " + executionPlanName + " deployed successfully.");
            }
        }

    }

    public void undeployExecutionPlan(String executionPlanFileName) {

        if (executionPlanFileMap.containsKey(executionPlanFileName)) {
            String executionPlanName = executionPlanFileMap.get(executionPlanFileName);
            executionPlanFileMap.remove(executionPlanFileName);

            if (executionPlanRunTimeMap.containsKey(executionPlanName)) {
                executionPlanRunTimeMap.get(executionPlanName).shutdown();
                executionPlanRunTimeMap.remove(executionPlanName);
            }

            if (executionPlanConfigurationMap.containsKey(executionPlanName)) {
                executionPlanConfigurationMap.remove(executionPlanName);
            }

            if (executionPlanSpecificInputHandlerMap.containsKey(executionPlanName)) {
                executionPlanSpecificInputHandlerMap.remove(executionPlanName);
            }

            log.info("Execution plan " + executionPlanName + " undeployed successfully.");
        }
    }

    public boolean delete(String executionPlanFileName) throws ExecutionPlanConfigurationException {

        if (executionPlanFileMap.containsValue(executionPlanFileName)) {
            ExecutionPlanFilesystemInvoker.delete(executionPlanFileName);
            return true;
        }
        return false;
    }

    public boolean save(String executionPlan) throws ExecutionPlanConfigurationException {
        ExecutionPlan parsedExecutionPlan = SiddhiCompiler.parse(executionPlan);
        Element nameAnnotation = AnnotationHelper.getAnnotationElement(EventProcessorConstants.ANNOTATION_NAME_NAME,
                null, parsedExecutionPlan.getAnnotations());

        if (nameAnnotation == null || nameAnnotation.getValue().isEmpty()) {
            throw new ExecutionPlanConfigurationException("Execution plan name must " +
                    "be provided as @Plan:name('name').");
        }

        String executionPlanName = nameAnnotation.getValue();
        if (!executionPlanRunTimeMap.containsKey(executionPlanName)) {
            SiddhiManager siddhiManager = StreamProcessorDataHolder.getSiddhiManager();
            ExecutionPlanRuntime executionPlanRuntime = siddhiManager.createExecutionPlanRuntime(executionPlan);
            if (executionPlanRuntime != null) {
                ExecutionPlanFilesystemInvoker.save(executionPlan, executionPlanName);
                return true;
            }
        }
        return false;
    }


    public Map<String, ExecutionPlanRuntime> getExecutionPlanRunTimeMap() {
        return executionPlanRunTimeMap;
    }

    public Map<String, Map<String, InputHandler>> getExecutionPlanSpecificInputHandlerMap() {
        return executionPlanSpecificInputHandlerMap;
    }

    public Map<String, ExecutionPlanConfiguration> getExecutionPlanConfigurationMap() {
        return executionPlanConfigurationMap;
    }
}
