/*
 * Copyright 2016 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;
using  RobotNet10.Shared.Numbers;

namespace CartographerSharp.Sensor;

/// <summary>
/// Range data structure.
/// Rays begin at 'origin'. 'returns' are the points where obstructions were
/// detected. 'misses' are points in the direction of rays for which no return
/// was detected, and were inserted at a configured distance. It is assumed that
/// between the 'origin' and 'misses' is free space.
/// </summary>
public struct RangeData(Vector3 origin, PointCloud returns, PointCloud misses)
{
    public Vector3 Origin { get; set; } = origin;
    public PointCloud Returns { get; set; } = returns;
    public PointCloud Misses { get; set; } = misses;
}

/// <summary>
/// Operations on RangeData.
/// </summary>
public static class RangeDataOperations
{
    /// <summary>
    /// Transforms range data according to a transform.
    /// </summary>
    public static RangeData Transform(RangeData rangeData, Rigid3f transform)
    {
        return new RangeData(
            transform.TransformPoint(rangeData.Origin),
            PointCloudOperations.Transform(rangeData.Returns, transform),
            PointCloudOperations.Transform(rangeData.Misses, transform)
        );
    }

    /// <summary>
    /// Normalizes range data origin to a target origin by translating all points.
    /// This is used in 2D SLAM to ensure consistent origin for ray casting in submap.
    /// </summary>
    public static RangeData NormalizeOrigin(RangeData rangeData, Vector3 targetOrigin)
    {
        var originOffset = targetOrigin - rangeData.Origin;
        return new RangeData(
            targetOrigin,
            PointCloudOperations.Translate(rangeData.Returns, originOffset),
            PointCloudOperations.Translate(rangeData.Misses, originOffset)
        );
    }

    /// <summary>
    /// Crops 'range_data' according to the region defined by 'min_z' and 'max_z'.
    /// </summary>
    public static RangeData Crop(RangeData rangeData, double minZ, double maxZ)
    {
        return new RangeData(
            rangeData.Origin,
            PointCloudOperations.Crop(rangeData.Returns, minZ, maxZ),
            PointCloudOperations.Crop(rangeData.Misses, minZ, maxZ)
        );
    }

    /// <summary>
    /// Converts 'range_data' to a proto::RangeData.
    /// </summary>
    public static Models.Sensor.RangeData ToProto(RangeData rangeData)
    {
        var proto = new Models.Sensor.RangeData
        {
            Origin = new Vector3f(rangeData.Origin.X, rangeData.Origin.Y, rangeData.Origin.Z),
            Returns = [],
            Misses = []
        };

        foreach (var point in rangeData.Returns.Points)
        {
            proto.Returns.Add(new Models.Sensor.RangefinderPoint
            {
                Position = new Vector3f(point.Position.X, point.Position.Y, point.Position.Z)
            });
        }

        foreach (var point in rangeData.Misses.Points)
        {
            proto.Misses.Add(new Models.Sensor.RangefinderPoint
            {
                Position = new Vector3f(point.Position.X, point.Position.Y, point.Position.Z)
            });
        }

        return proto;
    }

    /// <summary>
    /// Converts 'proto' to RangeData.
    /// </summary>
    public static RangeData FromProto(Models.Sensor.RangeData proto)
    {
        var returns = new List<Sensor.RangefinderPoint>();
        if (proto.Returns.Count > 0)
        {
            foreach (var protoPoint in proto.Returns)
            {
                returns.Add(new Sensor.RangefinderPoint(new Vector3(protoPoint.Position.X, protoPoint.Position.Y, protoPoint.Position.Z)));
            }
        }

        var misses = new List<Sensor.RangefinderPoint>();
        if (proto.Misses.Count > 0)
        {
            foreach (var protoPoint in proto.Misses)
            {
                misses.Add(new Sensor.RangefinderPoint(new Vector3(protoPoint.Position.X, protoPoint.Position.Y, protoPoint.Position.Z)));
            }
        }

        return new RangeData(
            new Vector3(proto.Origin.X, proto.Origin.Y, proto.Origin.Z),
            new PointCloud(returns),
            new PointCloud(misses)
        );
    }
}