/*
 *  Copyright (c) 2018 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 io.siddhi.extension.execution.map.test.util;

import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.mvel2.util.StringAppender;

@Plugin(name = "UnitTestAppender",
        category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE)
public class UnitTestAppender extends AbstractAppender {

    private StringAppender messages = new StringAppender();

    public UnitTestAppender(String name, Filter filter) {

        super(name, filter, null);
    }

    @PluginFactory
    public static UnitTestAppender createAppender(
            @PluginAttribute("name") String name,
            @PluginElement("Filter") Filter filter) {

        return new UnitTestAppender(name, filter);
    }

    public String getMessages() {

        String results = messages.toString();
        if (results.isEmpty()) {
            return null;
        }
        return results;
    }

    @Override
    public void append(LogEvent event) {

        messages.append(event.getMessage().getFormattedMessage());
    }

}
