/*

 * Copyright (c) 2018, 2019, 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.

 *

 * 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 org.graalvm.util;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.util.LinkedHashMap;

import java.util.Map;

/**

 * Facilities for encoding/decoding a set of options to/from a byte array.

 */

public final class OptionsEncoder {

    private OptionsEncoder() {

    }

    /**

     * Determines if {@code value} is supported by {@link #encode(Map)}.

     */

    public static boolean isValueSupported(Object value) {

        return TypedDataOutputStream.isValueSupported(value);

    }

    /**

     * Encodes {@code options} into a byte array.

     *

     * @throws IllegalArgumentException if any value in {@code options} is not

     *             {@linkplain #isValueSupported(Object) supported}

     */

    public static byte[] encode(final Map<String, Object> options) {

        try (ByteArrayOutputStream baout = new ByteArrayOutputStream()) {

            try (TypedDataOutputStream out = new TypedDataOutputStream(baout)) {

                out.writeInt(options.size());

                for (Map.Entry<String, Object> e : options.entrySet()) {

                    out.writeUTF(e.getKey());

                    try {

                        out.writeTypedValue(e.getValue());

                    } catch (IllegalArgumentException iae) {

                        throw new IllegalArgumentException(String.format("Key: %s, Value: %s, Value type: %s",

                                        e.getKey(), e.getValue(), e.getValue().getClass()), iae);

                    }

                }

            }

            return baout.toByteArray();

        } catch (IOException ioe) {

            throw new IllegalArgumentException(ioe);

        }

    }

    /**

     * Decodes {@code input} into a name/value map.

     *

     * @throws IllegalArgumentException if {@code input} cannot be decoded

     */

    public static Map<String, Object> decode(byte[] input) {

        Map<String, Object> res = new LinkedHashMap<>();

        try (TypedDataInputStream in = new TypedDataInputStream(new ByteArrayInputStream(input))) {

            final int size = in.readInt();

            for (int i = 0; i < size; i++) {

                final String key = in.readUTF();

                final Object value = in.readTypedValue();

                res.put(key, value);

            }

            if (in.available() != 0) {

                throw new IllegalArgumentException(in.available() + " undecoded bytes");

            }

        } catch (IOException ioe) {

            throw new IllegalArgumentException(ioe);

        }

        return res;

    }

}