package org.projectfloodlight.openflow.types;

import com.google.common.hash.PrimitiveSink;


public class Masked<T extends OFValueType<T>> implements OFValueType<Masked<T>> {
    protected final T value;

    /** bitmask of the value. Note: a set (1) bit in this mask means 'match on this value'.
     *  This the natural mask represenation as in IPv[46] netmasks. It is the inverse of the
     *  OpenFlow 1.0 'wildcard' meaning.
     */
    protected final T mask;

    protected Masked(T value, T mask) {
        this.value = value.applyMask(mask);
        this.mask = mask;
    }

    public T getValue() {
        return value;
    }

    public T getMask() {
        return mask;
    }

    public static <T extends OFValueType<T>> Masked<T> of(T value, T mask) {
        return new Masked<T>(value, mask);
    }

    @Override
    public int getLength() {
        return this.value.getLength() + this.mask.getLength();
    }

    @Override
    public String toString() {
        // General representation: value/mask
        StringBuilder sb = new StringBuilder();
        sb.append(value.toString()).append('/').append(mask.toString());
        return sb.toString();
    }

    /** Determine whether candidate value is matched by this masked value
     *  (i.e., does candiate lie in the 'network/range' specified by this masked
     *  value).
     *
     * @param candidate the candidate value to test
     * @return true iff the candidate lies in the area specified by this masked
     *         value.
     */
    public boolean matches(T candidate) {
        // candidate lies in the area of this masked value if its
        // value with the masked bit zero'ed out equals this's value
        // (e.g., our 'network address' for networks)
        return candidate.applyMask(this.mask).equals(this.value);
    }

    @Override
    public Masked<T> applyMask(Masked<T> mask) {
        return this;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Masked<?>))
            return false;
        Masked<?> mobj = (Masked<?>)obj;
        return this.value.equals(mobj.value) && this.mask.equals(mobj.mask);
    }

    @Override
    public int hashCode() {
        final int prime = 59;
        int result = 1;
        result = prime * result + this.value.hashCode();
        result = prime * result + this.mask.hashCode();
        return result;
    }

    @Override
    public int compareTo(Masked<T> o) {
        int res = value.compareTo(o.value);
        if(res != 0)
            return res;
        else
            return mask.compareTo(o.mask);
    }

    @Override
    public void putTo(PrimitiveSink sink) {
        value.putTo(sink);
        mask.putTo(sink);
    }
}