/*
 * Copyright 2017 The Cartographer Authors
 *
 * 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.
 */

using CartographerSharp.Models.Transform;
using CartographerSharp.Transform;

namespace CartographerSharp.Sensor;

/// <summary>
/// Landmark observation structure.
/// </summary>
public struct LandmarkObservation(string id, Rigid3d landmarkToTrackingTransform, double translationWeight, double rotationWeight)
{
    public string Id { get; set; } = id;
    public Rigid3d LandmarkToTrackingTransform { get; set; } = landmarkToTrackingTransform;
    public double TranslationWeight { get; set; } = translationWeight;
    public double RotationWeight { get; set; } = rotationWeight;
}

/// <summary>
/// Landmark data structure.
/// </summary>
public struct LandmarkData(long time, List<LandmarkObservation>? landmarkObservations = null)
{
    public long Time { get; set; } = time;
    public List<LandmarkObservation> LandmarkObservations { get; set; } = landmarkObservations ?? [];
}

/// <summary>
/// Operations on LandmarkData.
/// </summary>
public static class LandmarkDataOperations
{
    /// <summary>
    /// Converts 'landmark_data' to a proto::LandmarkData.
    /// </summary>
    public static Models.Sensor.LandmarkData ToProto(LandmarkData landmarkData)
    {
        var proto = new Models.Sensor.LandmarkData(landmarkData.Time, []);

        foreach (var observation in landmarkData.LandmarkObservations)
        {
            proto.LandmarkObservations.Add(new Models.Sensor.LandmarkData.LandmarkObservation(
                System.Text.Encoding.UTF8.GetBytes(observation.Id),
                (Rigid3dProto)observation.LandmarkToTrackingTransform,
                observation.TranslationWeight,
                observation.RotationWeight
            ));
        }

        return proto;
    }

    /// <summary>
    /// Converts 'proto' to an LandmarkData.
    /// </summary>
    public static LandmarkData FromProto(Models.Sensor.LandmarkData proto)
    {
        var observations = new List<LandmarkObservation>();
        foreach (var protoObservation in proto.LandmarkObservations)
        {
            observations.Add(new LandmarkObservation(
                System.Text.Encoding.UTF8.GetString(protoObservation.Id),
                (Rigid3d)protoObservation.LandmarkToTrackingTransform,
                protoObservation.TranslationWeight,
                protoObservation.RotationWeight
            ));
        }

        return new LandmarkData(proto.Timestamp, observations);
    }
}