/*
 * Copyright (c) 2016 Cisco and/or its affiliates.
 *
 * 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 io.fd.honeycomb.translate.v3po.util;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.net.InetAddresses;
import java.net.UnknownHostException;
import java.util.Arrays;
import javax.annotation.Nonnull;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4AddressNoZone;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;

/**
 * Trait providing logic for translation of ipv4-related data
 */
public interface Ipv4Translator extends ByteDataTranslator {

    /**
     * Creates address array from address part of {@link Ipv4Prefix}
     */
    default byte[] ipv4AddressPrefixToArray(@Nonnull final Ipv4Prefix ipv4Prefix) {
        checkNotNull(ipv4Prefix, "Cannot convert null prefix");

        byte[] retval = new byte[4];
        String[] address = ipv4Prefix.getValue().substring(0, ipv4Prefix.getValue().indexOf('/')).split("\\.");

        for (int d = 0; d < 4; d++) {
            retval[d] = (byte) (Short.parseShort(address[d]) & 0xff);
        }
        return retval;
    }

    /**
     * Extracts {@link Ipv4Prefix} prefix
     */
    default byte extractPrefix(Ipv4Prefix data) {
        checkNotNull(data, "Cannot extract from null");

        return Byte.valueOf(data.getValue().substring(data.getValue().indexOf('/') + 1));
    }

    /**
     * Converts byte array to {@link Ipv4Prefix} with specified prefixLength
     */
    default Ipv4Prefix arrayToIpv4Prefix(final byte[] address, byte prefixLength) {
        Ipv4AddressNoZone addressPart = arrayToIpv4AddressNoZone(address);

        return new Ipv4Prefix(addressPart.getValue().concat("/").concat(String.valueOf(prefixLength)));
    }

    /**
     * Parse byte array returned by VPP representing an Ipv4 address. Vpp returns IP byte arrays in reversed order.
     *
     * @return Ipv4AddressNoZone containing string representation of IPv4 address constructed from submitted bytes. No
     * change in order.
     */
    @Nonnull
    default Ipv4AddressNoZone arrayToIpv4AddressNoZone(@Nonnull byte[] ip) {
        // VPP sends ipv4 in a 16 byte array
        if (ip.length == 16) {
            ip = Arrays.copyOfRange(ip, 0, 4);
        }
        try {
            // Not reversing the byte array here!! because the IP coming from VPP is in reversed byte order
            // compared to byte order it was submitted
            return new Ipv4AddressNoZone(InetAddresses.toAddrString(InetAddresses.fromLittleEndianByteArray(ip)));
        } catch (UnknownHostException e) {
            throw new IllegalArgumentException("Unable to parse ipv4", e);
        }
    }

    /**
     * Parse byte array returned by VPP representing an Ipv4 address. Vpp returns IP byte arrays in reversed order.
     *
     * @return Ipv4AddressNoZone containing string representation of IPv4 address constructed from submitted bytes. No
     * change in order.
     */
    @Nonnull
    default Ipv4AddressNoZone arrayToIpv4AddressNoZoneReversed(@Nonnull byte[] ip) {
        // VPP sends ipv4 in a 16 byte array

        if (ip.length == 16) {
            ip = Arrays.copyOfRange(ip, 0, 4);
        }

        ip = reverseBytes(ip);

        try {
            // Not reversing the byte array here!! because the IP coming from VPP is in reversed byte order
            // compared to byte order it was submitted
            return new Ipv4AddressNoZone(InetAddresses.toAddrString(InetAddresses.fromLittleEndianByteArray(ip)));
        } catch (UnknownHostException e) {
            throw new IllegalArgumentException("Unable to parse ipv4", e);
        }
    }


    /**
     * Transform Ipv4 address to a byte array acceptable by VPP. VPP expects incoming byte array to be in the same order
     * as the address.
     *
     * @return byte array with address bytes
     */
    default byte[] ipv4AddressNoZoneToArray(final Ipv4AddressNoZone ipv4Addr) {
        return ipv4AddressNoZoneToArray(ipv4Addr.getValue());
    }

    default byte[] ipv4AddressNoZoneToArray(final String ipv4Addr) {
        byte[] retval = new byte[4];
        String[] dots = ipv4Addr.split("\\.");

        for (int d = 0; d < 4; d++) {
            retval[d] = (byte) (Short.parseShort(dots[d]) & 0xff);
        }
        return retval;
    }
}