/*
 * 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>
/// The fixed frame pose data (like GPS, pose, etc.) will be used in the optimization.
/// </summary>
public struct FixedFramePoseData(long time, Rigid3d? pose = null)
{
    public long Time { get; set; } = time;
    public Rigid3d? Pose { get; set; } = pose;
}

/// <summary>
/// Operations on FixedFramePoseData.
/// </summary>
public static class FixedFramePoseDataOperations
{
    /// <summary>
    /// Converts 'pose_data' to a proto::FixedFramePoseData.
    /// </summary>
    public static Models.Sensor.FixedFramePoseData ToProto(FixedFramePoseData poseData)
    {
        return new Models.Sensor.FixedFramePoseData(
            poseData.Time,
            poseData.Pose.HasValue ? (Rigid3dProto)poseData.Pose.Value : default
        );
    }

    /// <summary>
    /// Converts 'proto' to an FixedFramePoseData.
    /// </summary>
    public static FixedFramePoseData FromProto(Models.Sensor.FixedFramePoseData proto)
    {
        // Check if pose is set (equivalent to proto.has_pose() in C++)
        // In C#, since Rigid3dProto is a struct, we check if rotation quaternion is normalized
        // (a valid quaternion should have norm close to 1, default would be all zeros)
        Rigid3d? pose = null;
        var rot = proto.Pose.Rotation;
        var quatNorm = Math.Sqrt(rot.W * rot.W + rot.X * rot.X + rot.Y * rot.Y + rot.Z * rot.Z);
        // If quaternion is normalized (or close to normalized), pose is set
        if (quatNorm > 0.1) // Threshold to distinguish from default (0,0,0,0)
        {
            pose = (Rigid3d)proto.Pose;
        }
        
        return new FixedFramePoseData(
            proto.Timestamp,
            pose
        );
    }
}