TheVVaS-Assets/RPGCoreCommon/Select/Runtime/Select.cs

using System;
using RPGCoreCommon.Settings;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.UIElements;
using Object = UnityEngine.Object;

namespace RPGCoreCommon.Select
{
    public static class Select
    {
        private static IRuntimePanel _panel;
        
        private static IRuntimePanel GetPanel()
        {
            if (_panel != null) return _panel;
            
            const string documentUITag = "MainUIDocument";
            UIDocument uiDocument = null;

            try
            {
                // FIND BY TAG
                var go = GameObject.FindWithTag(documentUITag);
                if (go) uiDocument = go.GetComponent<UIDocument>();
            }
            catch (UnityException)
            {
                Debug.LogError($"Tag {documentUITag} not found! Please add it to the project.");
            }

            // FIND ANY UI DOCUMENT
            if (!uiDocument)
            {
                Debug.LogWarning($"Found no {nameof(UIDocument)} with tag '{documentUITag}', started looking for any on scene...");
                uiDocument = Object.FindAnyObjectByType<UIDocument>();
            }

            // PANEL NOT FOUND
            if (!uiDocument)
            {
                Debug.LogError($"Current scene has no {nameof(UIDocument)}! {nameof(Select)} won't work with UI!");
                return null;
            }

            _panel = uiDocument.runtimePanel;
            return _panel;
        }
        
        /// <summary>Get <see cref="GetFromUI"/> and if nothing selected then get <see cref="GetFromScene"/> instead.</summary>
        public static SelectUtilResult Get()
        {
            if (GetFromUI() is { hit: SelectType.UI } fromUI) return fromUI;
            if (GetFromScene() is { hit: SelectType.Scene } fromScene) return fromScene;
            return new SelectUtilResult();
        }

        /// <summary>Try to select anything from given position on UI that extends <see cref="ISelectableUI"/></summary>
        public static SelectUtilResult GetFromUI()
        {
            var mousePos = Mouse.current.position.ReadValue();
            mousePos.y = Screen.height - mousePos.y;
            var mousePosOnUI = RuntimePanelUtils.ScreenToPanel(GetPanel(), mousePos);

            return new SelectUtilResult(mousePosOnUI, GetPanel().Pick(mousePosOnUI));
        }

        /// <summary>
        /// TComponent is <see cref="Rigidbody"/> by default if not provided.<br/>
        /// <inheritdoc cref="GetFromScene{TComponent}"/>
        /// </summary>
        public static SelectUtilResult GetFromScene()
        {
            return GetFromScene<Rigidbody>();
        }

        /// <summary>
        /// Try to select <see cref="GameObject"/> with component of given type '<typeparamref name="TComponent"/>' in self or in any parent.
        /// If not found then gets <see cref="Collider"/>'s <see cref="GameObject"/>.
        /// </summary>
        /// <typeparam name="TComponent">Type of component to look for</typeparam>
        public static SelectUtilResult GetFromScene<TComponent>() where TComponent : Component
        {
            var hit = SelectHit();
        
            // Nothing hit - clicked void?
            if (!hit.collider) return new SelectUtilResult();
        
            var component = hit.collider.gameObject.GetComponentInParent<TComponent>();
            
            // Wanted component not found - get GameObject from Collider
            if (!component) return new SelectUtilResult(hit.point, hit.collider.gameObject);
        
            return new SelectUtilResult(hit.point, component.gameObject, component);
        }

        /// <summary>Returns Vector3 of clicked position</summary>
        public static Vector3 SelectPosition()
        {
            return SelectHit().point;
        }
        
        /// <summary>Returns <see cref="RaycastHit"/> of clicked position</summary>
        public static RaycastHit SelectHit()
        {
            Physics.Raycast(
                Camera.main.ScreenPointToRay(Mouse.current.position.ReadValue()),
                out var hit,
                Mathf.Infinity,
                SettingsManager.Get<SelectSettings>().collisionLayerMask);
        
            return hit;
        }
    }
}