/**
 * ============LICENSE_START====================================================
 * org.onap.aaf
 * ===========================================================================
 * Copyright (c) 2018 AT&T Intellectual Property. 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.
 * ============LICENSE_END====================================================
 *
 */

package org.onap.aaf.cadi.util;

/*
 * NetMask - a class to quickly validate whether a given IP is part of a mask, as defined by bytes or standard String format.
 *
 * Needs the IPV6 Mask Builder.
 */
public class NetMask {
    private long mask;

    public NetMask(byte[] inBytes) {
        mask = derive(inBytes);
    }

    public NetMask(String string) throws MaskFormatException {
        mask = derive(string,true);
    }

    public boolean isInNet(byte[] inBytes) {
        long addr = derive(inBytes);
        return (mask & addr) == addr;
    }

    public boolean isInNet(String str) {
        long addr;
        try {
            addr = derive(str,false);
            return (mask & addr) == addr;
        } catch (MaskFormatException e) {
            // will not hit this code;
            return false;
        }
    }

    public static long derive(byte[] inBytes) {
        long addr = 0L;
        int offset = inBytes.length*8;
        for (int i=0;i<inBytes.length;++i) {
            addr&=(inBytes[i]<<offset);
            offset-=8;
        }
        return addr;
    }

    public static long derive(String str, boolean check) throws MaskFormatException {
        long rv=0L;
        int idx=str.indexOf(':');
        int slash = str.indexOf('/');

        if (idx<0) { // Not IPV6, so it's IPV4... Is there a mask of 123/254?
            idx=str.indexOf('.');
            int offset = 24;
            int end = slash>=0?slash:str.length();
            int bits = slash>=0?Integer.parseInt(str.substring(slash+1)):32;
            if (check && bits>32) {
                throw new MaskFormatException("Invalid Mask Offset in IPV4 Address");
            }
            int prev = 0;
            long lbyte;
            while (prev<end) {
                if (idx<0) {
                    idx = end;
                }
                lbyte = Long.parseLong(str.substring(prev, idx));
                if (check && (lbyte>255 || lbyte<0)) {
                    throw new MaskFormatException("Invalid Byte in IPV4 Address");
                }
                rv|=lbyte<<offset;
                prev = ++idx;
                idx=str.indexOf('.',prev);
                offset-=8;
            }
            rv|=0x00000000FFFFFFFFL>>bits;
        }
        return rv;
    }

}