/*
 * Copyright (c) 2018-2019. Developed by Hedgecode.
 *
 * 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.hedgecode.chess.qrcode.zip;

import java.util.Arrays;
import java.util.Base64;

/**
 *
 *
 * @author Dmitry Samoshin aka gotty
 */
public class ZipContentUtils {

    private static final int LENGTH_BYTE_COUNT = 4;

    private static final int MAX_CONTENT_LENGTH = 65536;

    public static int getMaxContentLength() {
        return MAX_CONTENT_LENGTH;
    }

    public static int getZipLength(byte[] zipBytes) {
        return fromByteArray(
                Arrays.copyOf(zipBytes, LENGTH_BYTE_COUNT)
        );
    }

    public static byte[] getZipBytes(byte[] zipBytes) {
        return Arrays.copyOfRange(
                zipBytes, LENGTH_BYTE_COUNT, zipBytes.length
        );
    }

    public static byte[] concat(int length, byte[] bytes) {
        return concat(
                toByteArray(length),
                bytes
        );
    }

    public static String base64Encode(byte[] bytes) {
        return Base64.getEncoder().encodeToString(bytes);
    }

    public static byte[] base64Decode(String value) {
        return Base64.getDecoder().decode(value);
    }

    private static byte[] toByteArray(int value) {
        return new byte[] {
                (byte) (value >> 24),
                (byte) (value >> 16),
                (byte) (value >> 8),
                (byte) (value)
        };
    }

    private static int fromByteArray(byte[] bytes) {
        return bytes[0] << 24
                | (bytes[1] & 0xFF) << 16
                | (bytes[2] & 0xFF) << 8
                | (bytes[3] & 0xFF);
    }

    private static byte[] concat(byte[]... byteArrays) {
        int length = 0;
        for (byte[] bytes : byteArrays) {
            length += bytes.length;
        }
        byte[] concatBytes = new byte[length];
        length = 0;
        for (byte[] bytes : byteArrays) {
            if (bytes.length == 0)
                continue;
            System.arraycopy(bytes, 0, concatBytes, length, bytes.length);
            length += bytes.length;
        }
        return concatBytes;
    }

    private ZipContentUtils() {
        throw new AssertionError(
                "No org.hedgecode.chess.qrcode.zip.ZipContentUtils instances!"
        );
    }

}