/*
 *  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.synapse.commons.evaluators.config;

import org.apache.synapse.commons.evaluators.source.*;
import org.apache.synapse.commons.evaluators.EvaluatorConstants;
import org.apache.synapse.commons.evaluators.EvaluatorException;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMAttribute;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.xml.namespace.QName;

public abstract class TextProcessingEvaluatorFactory implements EvaluatorFactory {

    protected Log log = LogFactory.getLog(this.getClass());

    protected SourceTextRetriever getSourceTextRetriever(OMElement e) throws EvaluatorException {
        OMAttribute typeAttr = e.getAttribute(new QName(EvaluatorConstants.TYPE));
        OMAttribute sourceAttr = e.getAttribute(new QName(EvaluatorConstants.SOURCE));

        SourceTextRetriever textRetriever = null;
        if (typeAttr != null) {
            String value = typeAttr.getAttributeValue();
            if (value.equals(EvaluatorConstants.HEADER)) {
                if (sourceAttr != null) {
                    textRetriever = new HeaderTextRetriever(sourceAttr.getAttributeValue());
                } else {
                    handleException(EvaluatorConstants.SOURCE + " attribute is required");
                }
            } else if (value.equals(EvaluatorConstants.PARAM)) {
                if (sourceAttr != null) {
                    textRetriever = new ParameterTextRetriever(sourceAttr.getAttributeValue());
                } else {
                    handleException(EvaluatorConstants.SOURCE + " attribute is required");
                }
            } else if (value.equals(EvaluatorConstants.URL)) {
                textRetriever = new URLTextRetriever();
                if (sourceAttr != null) {
                    ((URLTextRetriever) textRetriever).setSource(sourceAttr.getAttributeValue());
                }
            } else if (value.equals(EvaluatorConstants.PROPERTY)) {
                if (sourceAttr != null) {
                    textRetriever = new PropertyTextRetriever(sourceAttr.getAttributeValue());
                } else {
                    handleException(EvaluatorConstants.SOURCE + " attribute is required");
                }
            } else if (value.equals(EvaluatorConstants.SOAP)) {
                if (sourceAttr != null) {
                    textRetriever = new SOAPEnvelopeTextRetriever(sourceAttr.getAttributeValue());
                } else {
                    handleException(EvaluatorConstants.SOURCE + " attribute is required");
                }
            } else {
                handleException("Unknown equal evaluator type: " + value);
            }

        } else {
            if (sourceAttr != null) {
                textRetriever = new HeaderTextRetriever(sourceAttr.getAttributeValue());
            } else {
                handleException(EvaluatorConstants.SOURCE + " attribute is required");
            }
        }

        return textRetriever;
    }

    protected void handleException(String message) throws EvaluatorException {
        log.error(message);
        throw new EvaluatorException(message);
    }
}