/*

 * Copyright (c) 2015, 2016, 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

 */

package java.net.http;

import java.util.Collections;

import java.util.List;

import java.util.Map;

import java.util.Optional;

import java.util.TreeMap;

import java.util.function.Predicate;

/**

 * Immutable HttpHeaders constructed from mutable HttpHeadersImpl.

 */

class ImmutableHeaders implements HttpHeaders {

    private final Map<String,List<String>> map;

    @SuppressWarnings("unchecked")

    ImmutableHeaders() {

        map = (Map<String,List<String>>)Collections.EMPTY_MAP;

    }

    // TODO: fix lower case issue. Must be lc for http/2 compares ignoreCase for http/1

    ImmutableHeaders(HttpHeadersImpl h, Predicate<String> keyAllowed) {

        Map<String,List<String>> src = h.directMap();

        Map<String,List<String>> m = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);

        src.forEach((key, value) -> {

            if (keyAllowed.test(key))

                m.put(key, Collections.unmodifiableList(value));

        });

        map = Collections.unmodifiableMap(m);

    }

    @Override

    public Optional<String> firstValue(String name) {

        List<String> l = map.get(name);

        String v = l == null ? null : l.get(0);

        return Optional.ofNullable(v);

    }

    @Override

    public Optional<Long> firstValueAsLong(String name) {

        return firstValue(name).map((v -> Long.parseLong(v)));

    }

    @Override

    public List<String> allValues(String name) {

        return map.get(name);

    }

    @Override

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

        return map;

    }

}