/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.internal.net.http.common;

import java.net.http.HttpHeaders;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.TreeMap;

import static jdk.internal.net.http.common.Utils.ACCEPT_ALL;

/** A mutable builder for collecting and building HTTP headers. */

public class HttpHeadersBuilder {

    private final TreeMap<String, List<String>> headersMap;

    public HttpHeadersBuilder() {

        headersMap = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);

    }

    public HttpHeadersBuilder structuralCopy() {

        HttpHeadersBuilder builder = new HttpHeadersBuilder();

        for (Map.Entry<String, List<String>> entry : headersMap.entrySet()) {

            List<String> valuesCopy = new ArrayList<>(entry.getValue());

            builder.headersMap.put(entry.getKey(), valuesCopy);

        }

        return builder;

    }

    public void addHeader(String name, String value) {

        headersMap.computeIfAbsent(name, k -> new ArrayList<>(1))

                  .add(value);

    }

    public void setHeader(String name, String value) {

        // headers typically have one value

        List<String> values = new ArrayList<>(1);

        values.add(value);

        headersMap.put(name, values);

    }

    public void clear() {

        headersMap.clear();

    }

    public Map<String, List<String>> map() {

        return headersMap;

    }

    public HttpHeaders build() {

        return HttpHeaders.of(headersMap, ACCEPT_ALL);

    }

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append(super.toString()).append(" { ");

        sb.append(map());

        sb.append(" }");

        return sb.toString();

    }

}