/*
 * Copyright (C) Photon Vision.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package org.photonvision.targeting;

import edu.wpi.first.math.geometry.Transform3d;
import edu.wpi.first.util.protobuf.ProtobufSerializable;
import org.photonvision.common.dataflow.structures.Packet;
import org.photonvision.common.dataflow.structures.PacketSerde;
import org.photonvision.targeting.proto.PNPResultProto;
import org.photonvision.utils.PacketUtils;

/**
 * The best estimated transformation from solvePnP, and possibly an alternate transformation
 * depending on the solvePNP method. If an alternate solution is present, the ambiguity value
 * represents the ratio of reprojection error in the best solution to the alternate (best /
 * alternate).
 *
 * <p>Note that the coordinate frame of these transforms depends on the implementing solvePnP
 * method.
 */
public class PNPResult implements ProtobufSerializable {
    /**
     * If this result is valid. A false value indicates there was an error in estimation, and this
     * result should not be used.
     */
    public final boolean isPresent;

    /**
     * The best-fit transform. The coordinate frame of this transform depends on the method which gave
     * this result.
     */
    public final Transform3d best;

    /** Reprojection error of the best solution, in pixels */
    public final double bestReprojErr;

    /**
     * Alternate, ambiguous solution from solvepnp. If no alternate solution is found, this is equal
     * to the best solution.
     */
    public final Transform3d alt;

    /** If no alternate solution is found, this is bestReprojErr */
    public final double altReprojErr;

    /** If no alternate solution is found, this is 0 */
    public final double ambiguity;

    /** An empty (invalid) result. */
    public PNPResult() {
        this.isPresent = false;
        this.best = new Transform3d();
        this.alt = new Transform3d();
        this.ambiguity = 0;
        this.bestReprojErr = 0;
        this.altReprojErr = 0;
    }

    public PNPResult(Transform3d best, double bestReprojErr) {
        this(best, best, 0, bestReprojErr, bestReprojErr);
    }

    public PNPResult(
            Transform3d best,
            Transform3d alt,
            double ambiguity,
            double bestReprojErr,
            double altReprojErr) {
        this.isPresent = true;
        this.best = best;
        this.alt = alt;
        this.ambiguity = ambiguity;
        this.bestReprojErr = bestReprojErr;
        this.altReprojErr = altReprojErr;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (isPresent ? 1231 : 1237);
        result = prime * result + ((best == null) ? 0 : best.hashCode());
        long temp;
        temp = Double.doubleToLongBits(bestReprojErr);
        result = prime * result + (int) (temp ^ (temp >>> 32));
        result = prime * result + ((alt == null) ? 0 : alt.hashCode());
        temp = Double.doubleToLongBits(altReprojErr);
        result = prime * result + (int) (temp ^ (temp >>> 32));
        temp = Double.doubleToLongBits(ambiguity);
        result = prime * result + (int) (temp ^ (temp >>> 32));
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        PNPResult other = (PNPResult) obj;
        if (isPresent != other.isPresent) return false;
        if (best == null) {
            if (other.best != null) return false;
        } else if (!best.equals(other.best)) return false;
        if (Double.doubleToLongBits(bestReprojErr) != Double.doubleToLongBits(other.bestReprojErr))
            return false;
        if (alt == null) {
            if (other.alt != null) return false;
        } else if (!alt.equals(other.alt)) return false;
        if (Double.doubleToLongBits(altReprojErr) != Double.doubleToLongBits(other.altReprojErr))
            return false;
        if (Double.doubleToLongBits(ambiguity) != Double.doubleToLongBits(other.ambiguity))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "PNPResult [isPresent="
                + isPresent
                + ", best="
                + best
                + ", bestReprojErr="
                + bestReprojErr
                + ", alt="
                + alt
                + ", altReprojErr="
                + altReprojErr
                + ", ambiguity="
                + ambiguity
                + "]";
    }

    public static final class APacketSerde implements PacketSerde<PNPResult> {
        @Override
        public int getMaxByteSize() {
            return 1 + (Double.BYTES * 7 * 2) + (Double.BYTES * 3);
        }

        @Override
        public void pack(Packet packet, PNPResult value) {
            packet.encode(value.isPresent);

            if (value.isPresent) {
                PacketUtils.packTransform3d(packet, value.best);
                PacketUtils.packTransform3d(packet, value.alt);
                packet.encode(value.bestReprojErr);
                packet.encode(value.altReprojErr);
                packet.encode(value.ambiguity);
            }
        }

        @Override
        public PNPResult unpack(Packet packet) {
            var present = packet.decodeBoolean();

            if (!present) {
                return new PNPResult();
            }

            var best = PacketUtils.unpackTransform3d(packet);
            var alt = PacketUtils.unpackTransform3d(packet);
            var bestEr = packet.decodeDouble();
            var altEr = packet.decodeDouble();
            var ambiguity = packet.decodeDouble();
            return new PNPResult(best, alt, ambiguity, bestEr, altEr);
        }
    }

    public static final APacketSerde serde = new APacketSerde();
    public static final PNPResultProto proto = new PNPResultProto();
}