using UnityEngine;
using Valve.VR;
using System;
using OpenVRUtil;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections.Generic;

public class DashboardOverlay : MonoBehaviour {
    public new Camera camera;
    public RenderTexture renderTexture;
    public GraphicRaycaster graphicRaycaster;
    public EventSystem eventSystem;
    private ulong dashboardHandle = OpenVR.k_ulOverlayHandleInvalid;
    private ulong thumbnailHandle = OpenVR.k_ulOverlayHandleInvalid;

    private void Start() {
        OpenVRUtil.System.InitOpenVR();

        (dashboardHandle, thumbnailHandle) = Overlay.CreateDashboardOverlay("f3.beamy.dash", "Beamy Panel");

        var filePath = Application.streamingAssetsPath + "/potionGroundy.png";
        Overlay.SetOverlayFromFile(thumbnailHandle, filePath);

        renderTexture = new RenderTexture(1024, 768, 16, RenderTextureFormat.ARGBFloat);
        camera.targetTexture = renderTexture;

        Overlay.SetOverlaySize(dashboardHandle, 2.5f);
        Overlay.FlipOverlayVertical(dashboardHandle);

        Overlay.SetOverlayMouseScale(dashboardHandle, renderTexture.width, renderTexture.height);
    }

    private void Update() {
        Overlay.SetOverlayRenderTexture(dashboardHandle, renderTexture);

        var vrEvent = new VREvent_t();
        var uncbVREvent = (uint)System.Runtime.InteropServices.Marshal.SizeOf(typeof(VREvent_t));

        while (OpenVR.Overlay.PollNextOverlayEvent(dashboardHandle, ref vrEvent, uncbVREvent)) {
            switch ((EVREventType)vrEvent.eventType) {
                case EVREventType.VREvent_MouseButtonDown:
                    vrEvent.data.mouse.y = renderTexture.height - vrEvent.data.mouse.y;
                    var button = GetButtonByPosition(new Vector2(vrEvent.data.mouse.x, vrEvent.data.mouse.y));
                    if (button != null) {
                        button.onClick.Invoke();
                    }
                    break;
            }
        }
    }

    private void OnApplicationQuit() {
        Overlay.DestroyOverlay(dashboardHandle);
    }

    private void OnDestroy() {
        OpenVRUtil.System.ShutdownOpenVR();
    }

    private Button GetButtonByPosition(Vector2 position) {
        var pointerEventData = new PointerEventData(eventSystem);
        pointerEventData.position = position;

        // List to save found elements.
        var raycastResultList = new List<RaycastResult>();
    
        // Find elements at pointerEventData position then save to raycastList.
        graphicRaycaster.Raycast(pointerEventData, raycastResultList);
    
        // Get buttons from saved list.
        var raycastResult = raycastResultList.Find(element => element.gameObject.GetComponent<Button>());
    
        // Return null if no button found.
        if (raycastResult.gameObject == null) {
            return null;
        }
    
        // Otherwise return found button.
        return raycastResult.gameObject.GetComponent<Button>();
    }
}