package net.onrc.onos.core.util;

import java.util.Objects;

import net.onrc.onos.core.util.serializers.IPv4NetDeserializer;
import net.onrc.onos.core.util.serializers.IPv4NetSerializer;

import org.codehaus.jackson.map.annotate.JsonDeserialize;
import org.codehaus.jackson.map.annotate.JsonSerialize;

/**
 * The class representing an IPv4 network address.
 * This class is immutable.
 */
@JsonDeserialize(using = IPv4NetDeserializer.class)
@JsonSerialize(using = IPv4NetSerializer.class)
public final class IPv4Net {
    private final IPv4 address;         // The IPv4 address
    private final short prefixLen;      // The prefix length

    /**
     * Default constructor.
     */
    public IPv4Net() {
        this.address = null;
        this.prefixLen = 0;
    }

    /**
     * Copy constructor.
     *
     * @param other the object to copy from.
     */
    public IPv4Net(IPv4Net other) {
        if (other.address != null) {
            this.address = new IPv4(other.address);
        } else {
            this.address = null;
        }
        this.prefixLen = other.prefixLen;
    }

    /**
     * Constructor for a given address and prefix length.
     *
     * @param address   the address to use.
     * @param prefixLen the prefix length to use.
     */
    public IPv4Net(IPv4 address, short prefixLen) {
        this.address = address;
        this.prefixLen = prefixLen;
    }

    /**
     * Constructor from a string.
     *
     * @param value the value to use.
     */
    public IPv4Net(String value) {
        String[] splits = value.split("/");
        if (splits.length != 2) {
            throw new IllegalArgumentException("Specified IPv4Net address must contain an IPv4 " +
                    "address and a prefix length separated by '/'");
        }
        this.address = new IPv4(splits[0]);
        this.prefixLen = Short.decode(splits[1]);
    }

    /**
     * Get the address value of the IPv4Net address.
     *
     * @return the address value of the IPv4Net address.
     */
    public IPv4 address() {
        return address;
    }

    /**
     * Get the prefix length value of the IPv4Net address.
     *
     * @return the prefix length value of the IPv4Net address.
     */
    public short prefixLen() {
        return prefixLen;
    }

    /**
     * Convert the IPv4Net value to an "address/prefixLen" string.
     *
     * @return the IPv4Net value as an "address/prefixLen" string.
     */
    @Override
    public String toString() {
        return this.address.toString() + "/" + this.prefixLen;
    }

    /**
     * Compares the value of two IPv4Net objects.
     * <p/>
     * Note the value of the IPv4 address is compared directly between the
     * objects, and must match exactly for the objects to be considered equal.
     * This may result in objects which represent the same IP prefix being
     * classified as unequal, because the unsignificant bits of the address
     * field don't match (the bits to the right of the prefix length).
     * <p/>
     * TODO Change this behavior so that objects that represent the same prefix
     * are classified as equal according to this equals method.
     *
     * @see Object#equals(Object)
     */
    @Override
    public boolean equals(Object other) {
        if (other == this) {
            return true;
        }

        if (!(other instanceof IPv4Net)) {
            return false;
        }

        IPv4Net otherIpv4Net = (IPv4Net) other;

        return Objects.equals(this.address, otherIpv4Net.address)
                && this.prefixLen == otherIpv4Net.prefixLen;
    }

    @Override
    public int hashCode() {
        return Objects.hash(address, prefixLen);
    }
}