
/*
 * Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) 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.
 */

package org.wso2.msf4j.formparam.util;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

/**
 * <p> This class provides support for accessing the headers for a file or form
 * item that was received within a <code>multipart/form-data</code> POST
 * request.</p>
 */
public class FormItemHeader implements Serializable {

    /**
     * Serial version UID, being used, if serialized.
     */
    private static final long serialVersionUID = -4455695752627032559L;

    /**
     * Map of <code>String</code> keys to a <code>List</code> of
     * <code>String</code> instances.
     */
    private final Map<String, List<String>> headerNameToValueListMap = new LinkedHashMap<>();

    /**
     * {@inheritDoc}
     */
    public String getHeader(String name) {
        String nameLower = name.toLowerCase(Locale.ENGLISH);
        List<String> headerValueList = headerNameToValueListMap.get(nameLower);
        if (null == headerValueList) {
            return null;
        }
        return headerValueList.get(0);
    }

    /**
     * {@inheritDoc}
     */
    public Iterator<String> getHeaderNames() {
        return headerNameToValueListMap.keySet().iterator();
    }

    /**
     * {@inheritDoc}
     */
    public Iterator<String> getHeaders(String name) {
        String nameLower = name.toLowerCase(Locale.ENGLISH);
        List<String> headerValueList = headerNameToValueListMap.get(nameLower);
        if (null == headerValueList) {
            headerValueList = Collections.emptyList();
        }
        return headerValueList.iterator();
    }

    /**
     * Method to add header values to this instance.
     *
     * @param name name of this header
     * @param value value of this header
     */
    public synchronized void addHeader(String name, String value) {
        String nameLower = name.toLowerCase(Locale.ENGLISH);
        List<String> headerValueList = headerNameToValueListMap.get(nameLower);
        if (null == headerValueList) {
            headerValueList = new ArrayList<>();
            headerNameToValueListMap.put(nameLower, headerValueList);
        }
        headerValueList.add(value);
    }

}
