/**
* Copyright (c) 2021 Vuplex Inc. All rights reserved.
*
* Licensed under the Vuplex Commercial Software Library License, you may
* not use this file except in compliance with the License. You may obtain
* a copy of the License at
*
*     https://vuplex.com/commercial-library-license
*
* 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 System;
using UnityEngine;
using UnityEngine.EventSystems;
#if NET_4_6 || NET_STANDARD_2_0
using System.Threading.Tasks;
#endif

namespace Vuplex.WebView
{

    /// <summary>
    /// `WebViewPrefab` is a prefab that makes it easy to view and interact with web content in world space.
    /// It takes care of creating an `IWebView`, displaying its texture, and handling pointer interactions
    /// from the user (i.e. clicking, dragging, and scrolling). So, all you need to do is specify a URL or HTML to load,
    /// and then the user can view and interact with it. For use in a Canvas, see `CanvasWebViewPrefab` instead.
    /// </summary>
    /// <remarks>
    /// There are two ways to create a `WebViewPrefab`:
    /// 1. By dragging WebViewPrefab.prefab into your scene via the editor and then setting its "Initial URL" property.
    /// 2. Or by creating an instance programmatically with `WebViewPrefab.Instantiate()`, waiting for
    ///    it to initialize, and then calling methods on its `WebView` property (like `webViewPrefab.WebView.LoadUrl("https://vuplex.com")`).
    ///
    /// `WebViewPrefab` handles standard events from Unity's input event system
    /// (like `IPointerDownHandler` and `IScrollHandler`), so it works with input modules that plug into the event system,
    /// like Unity's `StandaloneInputModule` and the Oculus `OVRInputModule`.
    ///
    /// If your use case requires a high degree of customization, you can instead create an `IWebView`
    /// outside of the prefab with `Web.CreateWebView()`.
    /// </remarks>
    [HelpURL("https://developer.vuplex.com/webview/WebViewPrefab")]
    public class WebViewPrefab : BaseWebViewPrefab
    {

        /// <summary>
        /// The prefab's collider.
        /// </summary>
        public Collider Collider
        {
            get
            {
                return _view.GetComponent<Collider>();
            }
        }

        /// <summary>
        /// Sets the webview's initial resolution in pixels per Unity unit.
        /// You can change the resolution to make web content appear larger or smaller.
        /// For more information on scaling web content, see
        /// [this support article](https://support.vuplex.com/articles/how-to-scale-web-content).
        /// </summary>
        [Label("Initial Resolution (px / Unity unit)")]
        [Tooltip("You can change this to make web content appear larger or smaller.")]
        [HideInInspector]
        public float InitialResolution = 1300;

        [Obsolete("The static WebViewPrefab.ScrollSensitivity property is obsolete. Please use one of the following instance properties instead: WebViewPrefab.ScrollingSensitivity or CanvasWebViewPrefab.ScrollingSensitivity.")]
        public static float ScrollSensitivity { get; set; }

        /// <summary>
        /// Allows the scroll sensitivity to be adjusted.
        /// The default sensitivity is 0.005.
        /// </summary>
        [HideInInspector]
        public float ScrollingSensitivity = 0.005f;

        [Obsolete("WebViewPrefab.Init() has been removed. The WebViewPrefab script now initializes itself automatically, so Init() no longer needs to be called.", true)]
        public void Init() { }

        [Obsolete("WebViewPrefab.Init() has been removed. The WebViewPrefab script now initializes itself automatically, so Init() no longer needs to be called.", true)]
        public void Init(float width, float height) { }

        /// <summary>
        /// Like `Init(float, float)`, except it also accepts an object
        /// of options flags that can be used to alter the webview's behavior.
        /// </summary>
        [Obsolete("WebViewPrefab.Init() has been removed. The WebViewPrefab script now initializes itself automatically, so Init() no longer needs to be called.", true)]
        public void Init(float width, float height, WebViewOptions options) { }

        [Obsolete("WebViewPrefab.Init() has been removed. The WebViewPrefab script now initializes itself automatically, so Init() no longer needs to be called.", true)]
        public void Init(IWebView webView) { }

        /// <summary>
        /// Converts the given world position to a normalized screen point.
        /// </summary>
        /// <returns>
        /// A point where the x and y components are normalized
        /// values between 0 and 1.
        /// </returns>
        public Vector2 ConvertToScreenPoint(Vector3 worldPosition)
        {

            var localPosition = _viewResizer.transform.InverseTransformPoint(worldPosition);
            return new Vector2(1 - localPosition.x, -1 * localPosition.y);
        }

        /// <summary>
        /// Resizes the prefab mesh and webview to the given dimensions in Unity units.
        /// </summary>
        /// <remarks>
        /// A webview's default resolution is 1300px per Unity unit but can be changed
        /// with `IWebView.SetResolution()`.
        /// </remarks>
        public void Resize(float width, float height)
        {

            if (_webView != null)
            {
                _webView.Resize(width, height);
            }
            _setViewSize(width, height);
        }

        WebViewOptions _optionsForInitialization;
        Vector2 _sizeForInitialization = Vector2.zero;
        [SerializeField]
        [HideInInspector]
        Transform _videoRectPositioner;
        [SerializeField]
        [HideInInspector]
        protected Transform _viewResizer;
        IWebView _webViewForInitialization;

        protected override Vector2 _convertRatioPointToUnityUnits(Vector2 point)
        {

            var unityUnitsX = _viewResizer.transform.localScale.x * point.x;
            var unityUnitsY = _viewResizer.transform.localScale.y * point.y;
            return new Vector2(unityUnitsX, unityUnitsY);
        }

        protected override float _getInitialResolution()
        {

            return InitialResolution;
        }

        protected override float _getScrollingSensitivity()
        {

            return ScrollingSensitivity;
        }

        protected override ViewportMaterialView _getVideoLayer()
        {

            return _videoRectPositioner.GetComponentInChildren<ViewportMaterialView>();
        }

        protected override ViewportMaterialView _getView()
        {

            return transform.Find("WebViewPrefabResizer/WebViewPrefabView").GetComponent<ViewportMaterialView>();
        }

        void _initWebViewPrefab()
        {

#if VUPLEX_XR_INTERACTION_TOOLKIT
                WebViewLogger.LogWarning("It looks like you're using a WebViewPrefab with XR Interaction Toolkit. Please use a CanvasWebViewPrefab inside a world space Canvas instead. For more information, please see <em>https://support.vuplex.com/articles/xr-interaction-toolkit</em>.");
#endif

#if UNITY_ANDROID && UNITY_2018_2_OR_NEWER
                if (UnityEngine.Rendering.GraphicsSettings.useScriptableRenderPipelineBatching) {
                    WebViewLogger.LogError("URP settings error: \"SRP Batcher\" is enabled in Universal Render Pipeline (URP) settings, but URP for Android has an issue that prevents 3D WebView's textures from showing up outside of a Canvas. Please either go to \"UniversalRenderPipelineAsset\" -> \"Advanced\" and disable SRP Batcher or switch to using CanvasWebViewPrefab.");
                }
#endif

            if (_sizeForInitialization == Vector2.zero)
            {
                // The size was set via the editor instead of through arguments to Instantiate().
                _sizeForInitialization = transform.localScale;
                _resetLocalScale();
            }
            var width = _sizeForInitialization.x;
            var height = _sizeForInitialization.y;
            _viewResizer = transform.GetChild(0);
            _videoRectPositioner = _viewResizer.Find("VideoRectPositioner");
            _setViewSize(width, height);
            _init(width, height, _optionsForInitialization, _webViewForInitialization);
        }

        /// <summary>
        /// The top-level WebViewPrefab object's scale must be (1, 1),
        /// so the scale that was set via the editor is transferred from WebViewPrefab
        /// to WebViewPrefabResizer, and WebViewPrefab is moved to compensate
        /// for how WebViewPrefabResizer is moved in _setViewSize.
        /// </summary>
        void _resetLocalScale()
        {

            var localScale = transform.localScale;
            var localPosition = transform.localPosition;
            transform.localScale = new Vector3(1, 1, localScale.z);
            var offsetMagnitude = 0.5f * localScale.x;
            transform.localPosition = transform.localPosition + Quaternion.Euler(transform.localEulerAngles) * new Vector3(offsetMagnitude, 0, 0);
        }

        protected override void _setVideoLayerPosition(Rect videoRect)
        {

            // The origins of the prefab and the video rect are in their top-right
            // corners instead of their top-left corners.
            _videoRectPositioner.localPosition = new Vector3(
                1 - (videoRect.x + videoRect.width),
                -1 * videoRect.y,
                _videoRectPositioner.localPosition.z
            );
            _videoRectPositioner.localScale = new Vector3(videoRect.width, videoRect.height, _videoRectPositioner.localScale.z);
        }

        void _setViewSize(float width, float height)
        {

            var depth = _viewResizer.localScale.z;
            _viewResizer.localScale = new Vector3(width, height, depth);
            var localPosition = _viewResizer.localPosition;
            // Set the view resizer so that its middle aligns with the middle of this parent class's gameobject.
            localPosition.x = width * -0.5f;
            _viewResizer.localPosition = localPosition;
        }

        void Start()
        {

            _initWebViewPrefab();
        }
    }
}