using Microsoft.JSInterop;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Blog3000.Client.Utils
{
    /// <summary>
    /// See this for more infos on await promises:
    /// https://toddlittlejohn.com/2019/09/15/blazor-javascript-interoperability/
    /// </summary>
    public static class PromiseInvoker
    {
        public class PromiseInvokerCallback<T>
        {
            public readonly TaskCompletionSource<T> tcs = new TaskCompletionSource<T>();
            
            [JSInvokable("SetResult")]
            public void SetResult(T o)
            {                
                tcs.SetResult(o);
            }


            [JSInvokable("SetException")]
            public void SetException(string s)
            {
                tcs.SetException(new InvalidOperationException(s));
            }
        }


        public static async Task<T> InvokePromiseAsync<T>(this IJSRuntime jsRuntime, string funcName, params object[] prms)
        {
            var cb = new PromiseInvokerCallback<T>();
            object[] fp = new object[(prms?.Length ?? 0) + 1];
            fp[0] = DotNetObjectReference.Create(cb);
            if (prms != null && prms.Length > 0)
            {
                Array.Copy(prms, 0, fp, 1, prms.Length);
            }
            _ = jsRuntime.InvokeAsync<T>(funcName, fp);
            return await cb.tcs.Task;

            //return await InvokePromise<T>(jsRuntime, funcName, prms);
        }


        public static Task<T> InvokePromise<T>(this IJSRuntime jsRuntime, string funcName, params object[] prms)
        {
            var cb = new PromiseInvokerCallback<T>();
            object[] fp = new object[(prms?.Length ?? 0) + 1];
            fp[0] = DotNetObjectReference.Create(cb);
            if (prms != null && prms.Length > 0)
            {
                Array.Copy(prms, 0, fp, 1, prms.Length);
            }
            jsRuntime.InvokeAsync<T>(funcName, fp);
            return cb.tcs.Task;
        }


    }
}