/*-
 * ============LICENSE_START=======================================================
 *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
 * ================================================================================
 * 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.
 * 
 * SPDX-License-Identifier: Apache-2.0
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.apex.service.parameters.carriertechnology;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;

import org.onap.policy.apex.service.engine.event.impl.eventrequestor.EventRequestorCarrierTechnologyParameters;
import org.onap.policy.apex.service.engine.event.impl.filecarrierplugin.FileCarrierTechnologyParameters;
import org.onap.policy.common.parameters.ParameterRuntimeException;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;

/**
 * This class deserialises various type of carrier technology parameters from JSON.
 *
 * @author Liam Fallon (liam.fallon@ericsson.com)
 */
public class CarrierTechnologyParametersJsonAdapter
        implements JsonSerializer<CarrierTechnologyParameters>, JsonDeserializer<CarrierTechnologyParameters> {

    private static final XLogger LOGGER = XLoggerFactory.getXLogger(CarrierTechnologyParametersJsonAdapter.class);

    // Recurring string constants
    private static final String VALUE_TAG = "\" value \"";
    private static final String CARRIER_TECHNOLOGY_PREAMBLE = "carrier technology \"";


    private static final String PARAMETER_CLASS_NAME = "parameterClassName";

    private static final String CARRIER_TECHNOLOGY_TOKEN = "carrierTechnology";
    private static final String CARRIER_TECHNOLOGY_PARAMETERS = "parameters";

    // Built in technology parameters
    private static final Map<String, String> BUILT_IN_CARRIER_TECHNOLOGY_PARMETER_CLASS_MAP = new HashMap<>();

    static {
        BUILT_IN_CARRIER_TECHNOLOGY_PARMETER_CLASS_MAP.put("FILE",
                FileCarrierTechnologyParameters.class.getName());
        BUILT_IN_CARRIER_TECHNOLOGY_PARMETER_CLASS_MAP.put("EVENT_REQUESTOR",
                EventRequestorCarrierTechnologyParameters.class.getName());
    }

    /*
     * (non-Javadoc)
     *
     * @see com.google.gson.JsonSerializer#serialize(java.lang.Object, java.lang.reflect.Type,
     * com.google.gson.JsonSerializationContext)
     */
    @Override
    public JsonElement serialize(final CarrierTechnologyParameters src, final Type typeOfSrc,
            final JsonSerializationContext context) {
        final String returnMessage = "serialization of Apex carrier technology parameters to Json is not supported";
        LOGGER.error(returnMessage);
        throw new ParameterRuntimeException(returnMessage);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.google.gson.JsonDeserializer#deserialize(com.google.gson.JsonElement,
     * java.lang.reflect.Type, com.google.gson.JsonDeserializationContext)
     */
    @Override
    public CarrierTechnologyParameters deserialize(final JsonElement json, final Type typeOfT,
            final JsonDeserializationContext context) {
        final JsonObject jsonObject = json.getAsJsonObject();

        // Get the carrier technology label primitive
        final JsonPrimitive labelJsonPrimitive = (JsonPrimitive) jsonObject.get(CARRIER_TECHNOLOGY_TOKEN);

        // Check if we found our carrier technology
        if (labelJsonPrimitive == null) {
            LOGGER.warn("carrier technology parameter \"" + CARRIER_TECHNOLOGY_TOKEN + "\" not found in JSON file");
            return null;
        }

        // Get and check the carrier technology label
        final String carrierTechnologyLabel = labelJsonPrimitive.getAsString().replaceAll("\\s+", "");
        if (carrierTechnologyLabel == null || carrierTechnologyLabel.length() == 0) {
            final String errorMessage = "carrier technology parameter \"" + CARRIER_TECHNOLOGY_TOKEN + VALUE_TAG
                    + labelJsonPrimitive.getAsString() + "\" invalid in JSON file";
            LOGGER.warn(errorMessage);
            throw new ParameterRuntimeException(errorMessage);
        }

        // We now get the technology carrier parameter class
        String carrierTechnologyParameterClassName = null;

        // Get the technology carrier parameter class for the carrier technology plugin class from
        // the configuration parameters
        final JsonPrimitive classNameJsonPrimitive = (JsonPrimitive) jsonObject.get(PARAMETER_CLASS_NAME);

        // If no technology carrier parameter class was specified, we try to use a built in carrier
        // technology
        if (classNameJsonPrimitive == null) {
            carrierTechnologyParameterClassName =
                    BUILT_IN_CARRIER_TECHNOLOGY_PARMETER_CLASS_MAP.get(carrierTechnologyLabel);
        } else {
            // We use the specified one
            carrierTechnologyParameterClassName = classNameJsonPrimitive.getAsString().replaceAll("\\s+", "");
        }

        // Check the carrier technology parameter class
        if (carrierTechnologyParameterClassName == null || carrierTechnologyParameterClassName.length() == 0) {
            final String errorMessage = CARRIER_TECHNOLOGY_PREAMBLE + carrierTechnologyLabel + "\" parameter \""
                    + PARAMETER_CLASS_NAME + VALUE_TAG
                    + (classNameJsonPrimitive != null ? classNameJsonPrimitive.getAsString() : "null")
                    + "\" invalid in JSON file";
            LOGGER.warn(errorMessage);
            throw new ParameterRuntimeException(errorMessage);
        }

        // Get the class for the carrier technology
        Class<?> carrierTechnologyParameterClass = null;
        try {
            carrierTechnologyParameterClass = Class.forName(carrierTechnologyParameterClassName);
        } catch (final ClassNotFoundException e) {
            final String errorMessage =
                    CARRIER_TECHNOLOGY_PREAMBLE + carrierTechnologyLabel + "\" parameter \"" + PARAMETER_CLASS_NAME
                            + VALUE_TAG + carrierTechnologyParameterClassName + "\", could not find class";
            LOGGER.warn(errorMessage, e);
            throw new ParameterRuntimeException(errorMessage, e);
        }

        // Deserialise the class
        CarrierTechnologyParameters carrierTechnologyParameters =
                context.deserialize(jsonObject.get(CARRIER_TECHNOLOGY_PARAMETERS), carrierTechnologyParameterClass);
        if (carrierTechnologyParameters == null) {
            // OK no parameters for the carrier technology have been specified, just instantiate the
            // default parameters
            try {
                carrierTechnologyParameters =
                        (CarrierTechnologyParameters) carrierTechnologyParameterClass.newInstance();
            } catch (final Exception e) {
                final String errorMessage = "could not create default parameters for carrier technology \""
                        + carrierTechnologyLabel + "\"\n" + e.getMessage();
                LOGGER.warn(errorMessage, e);
                throw new ParameterRuntimeException(errorMessage, e);
            }
        }

        // Check that the carrier technology label matches the label in the carrier technology
        // parameters object
        if (!carrierTechnologyParameters.getLabel().equals(carrierTechnologyLabel)) {
            final String errorMessage = CARRIER_TECHNOLOGY_PREAMBLE + carrierTechnologyLabel
                            + "\" does not match plugin \""
                    + carrierTechnologyParameters.getLabel() + "\" in \"" + carrierTechnologyParameterClassName
                    + "\", specify correct carrier technology parameter plugin in parameter \"" + PARAMETER_CLASS_NAME
                    + "\"";
            LOGGER.warn(errorMessage);
            throw new ParameterRuntimeException(errorMessage);
        }

        return carrierTechnologyParameters;
    }
}