Collision Listener for Morpeh-ECS

CollisionListener.cs

    using System;
    using System.Diagnostics;
    using Morpeh;
    using UnityEngine;
    using Utils;

    [AddComponentMenu("")]
    public sealed class CollisionListener : MonoBehaviour {
        public IEntity    ownerEntity;
        public Collider[] colliders;
        public bool       isTrigger;
        public bool       handleExits;

        private World world;

        public CollisionListener Init(World world, IEntity ownerEntity, bool isTrigger, bool handleExits) {
            this.world       = world;
            this.ownerEntity = ownerEntity;
            this.isTrigger   = isTrigger;
            this.handleExits = handleExits;
            return this;
        }

        private void OnEnable() {
            this.colliders = this.GetComponentsInChildren<Collider>();

#if DEBUG
            if (this.colliders.Length <= 0) {
                throw new Exception($"There are no any {nameof(Collider)} to handle collisions on {this.name}");
            }
#endif
        }

        private void OnCollisionEnter(Collision other) {
            if (this.isTrigger) return;
            this.ThrowIfOwnerNotCompatible();

            ref var evt = ref this.world.CreateEntity().AddComponent<CollisionEnterEvent>();
            evt.ownerEntity     = this.ownerEntity;
            evt.ownerGameObject = this.gameObject;

            if (other.rigidbody != null) {
                evt.otherGameObject = other.rigidbody.gameObject;
                evt.otherEntity     = evt.otherGameObject.GetComponent<CollisionListener>()?.ownerEntity;
            }
            else {
                evt.otherGameObject = other.gameObject;
            }
        }

        private void OnCollisionExit(Collision other) {
            if (this.isTrigger || !this.handleExits) return;
            this.ThrowIfOwnerNotCompatible();

            ref var evt = ref this.world.CreateEntity().AddComponent<CollisionExitEvent>();
            evt.ownerEntity     = this.ownerEntity;
            evt.ownerGameObject = this.gameObject;

            if (other.rigidbody != null) {
                evt.otherGameObject = other.rigidbody.gameObject;
                evt.otherEntity     = evt.otherGameObject.GetComponent<CollisionListener>()?.ownerEntity;
            }
            else {
                evt.otherGameObject = other.gameObject;
            }
        }

        private void OnTriggerEnter(Collider other) {
            if (!this.isTrigger) return;
            this.ThrowIfOwnerNotCompatible();

            ref var evt = ref this.world.CreateEntity().AddComponent<TriggerEnterEvent>();
            evt.ownerEntity     = this.ownerEntity;
            evt.ownerGameObject = this.gameObject;

            if (other.attachedRigidbody != null) {
                evt.otherGameObject = other.attachedRigidbody.gameObject;
                evt.otherEntity     = evt.otherGameObject.GetComponent<CollisionListener>()?.ownerEntity;
            }
            else {
                evt.otherGameObject = other.gameObject;
            }
        }

        private void OnTriggerExit(Collider other) {
            if (!this.isTrigger || !this.handleExits) return;
            this.ThrowIfOwnerNotCompatible();

            ref var evt = ref this.world.CreateEntity().AddComponent<TriggerExitEvent>();
            evt.ownerEntity     = this.ownerEntity;
            evt.ownerGameObject = this.gameObject;

            if (other.attachedRigidbody != null) {
                evt.otherGameObject = other.attachedRigidbody.gameObject;
                evt.otherEntity     = evt.otherGameObject.GetComponent<CollisionListener>()?.ownerEntity;
            }
            else {
                evt.otherGameObject = other.gameObject;
            }
        }

        [Conditional("DEBUG")]
        private void ThrowIfOwnerNotCompatible() {
            if (!this.ownerEntity.Exists()) {
                throw new Exception($"{nameof(this.ownerEntity)} not exists!");
            }

            if (!this.isTrigger && !this.ownerEntity.Has<ReadyToCollision>()) {
                throw new Exception($"{nameof(this.ownerEntity)} should have {nameof(ReadyToCollision)}");
            }

            if (this.isTrigger && !this.ownerEntity.Has<ReadyToTrigger>()) {
                throw new Exception($"{nameof(this.ownerEntity)} should have {nameof(ReadyToTrigger)}");
            }
        }
    }