using System.Text;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using SFB;
using UnityEngine.Events;
using UniRx;
using System;
using UnityEngine.Networking;

[RequireComponent(typeof(Button))]
public class OpenImage : MonoBehaviour, IPointerDownHandler
{
    public Image Output;
    public UnityAction<Texture2D> OnLoadTextureFinished;
    public bool PreserveAspect = true;

    //public ViewOriginalImage OriginalImage;

#if UNITY_WEBGL && !UNITY_EDITOR
    //
    // WebGL
    //
    [DllImport("__Internal")]
    private static extern void UploadFile(string gameObjectName, string methodName, string filter, bool multiple);

    public void OnPointerDown(PointerEventData eventData) {
        if(eventData.button== PointerEventData.InputButton.Left)
        {
            UploadFile(gameObject.name, "OnFileUpload", ".png, .jpg,.bmp", false);
        }
        
    }

    // Called from browser
    public void OnFileUpload(string url) {
        StartCoroutine(OutputRoutine(url));
    }
#else
    public void OnPointerDown(PointerEventData eventData) 
    { 
    }
    // Start is called before the first frame update
    void Start()
    {
        GetComponent<Button>().OnClickAsObservable()
            .Subscribe(_ => OnClick());
    }

    private void OnClick()
    {
        var extensions = new[] {
                new ExtensionFilter("Image Files", "png", "jpg", "jpeg" ),
            };
        var paths = StandaloneFileBrowser.OpenFilePanel("Title", "", extensions, false);
        if (paths.Length > 0)
        {
            StartCoroutine(OutputRoutine(new Uri(paths[0]).AbsoluteUri));
        }
    }
#endif
    private IEnumerator OutputRoutine(string url)
    {
        UnityWebRequest uwr = new UnityWebRequest(url);
        DownloadHandlerTexture downloadTexture = new DownloadHandlerTexture(true);
        uwr.downloadHandler = downloadTexture;
        yield return uwr.SendWebRequest();
        if (!(uwr.isNetworkError || uwr.isHttpError))
        {
            var loader = downloadTexture.texture;
            Output.sprite = Sprite.Create(loader, new Rect(0, 0, loader.width, loader.height), Vector2.zero);
            Output.preserveAspect = PreserveAspect;

            OnLoadTextureFinished?.Invoke(loader);

        }
    }

   
}