@using System.Timers
@using BTCPayServer.Abstractions.Extensions
@using BTCPayServer.Blazor
@using BTCPayServer.Client
@using BTCPayServer.Data
@using BTCPayServer.Security
@using Microsoft.AspNetCore.Authorization
@using Microsoft.AspNetCore.Components.Authorization
@using Microsoft.AspNetCore.Http
@using Microsoft.AspNetCore.Identity
@using Microsoft.AspNetCore.Mvc
@using Microsoft.AspNetCore.Routing
@using Microsoft.Extensions.Localization
@inject AuthenticationStateProvider AuthenticationStateProvider
@inject IAuthorizationService AuthorizationService
@inject UserManager<ApplicationUser> UserManager
@inject UserLoginCodeService UserLoginCodeService
@inject LinkGenerator LinkGenerator
@inject IHttpContextAccessor HttpContextAccessor
@inject IStringLocalizer StringLocalizer
@implements IDisposable

@if (!string.IsNullOrEmpty(_data))
{
    <div @attributes="Attrs" class="@CssClass">
        <div class="qr-container mb-2">
            <QrCode Data="@_data" Size="Size"/>
        </div>
        <p class="text-center text-muted mb-1" id="progress">@StringLocalizer["Valid for {0} seconds", _seconds]</p>
        <div class="progress only-for-js" data-bs-toggle="tooltip" data-bs-placement="top">
            <div class="progress-bar progress-bar-striped progress-bar-animated @(Percent < 15 ? "bg-warning" : null)" role="progressbar" style="width:@Percent%" id="progressbar"></div>
        </div>
    </div>
}

@code {
    [Parameter]
    public string RedirectUrl { get; set; }

    [Parameter]
    public int Size { get; set; } = 256;
    [Parameter]
    public string ImpersonatedUserId { get; set; }

    [Parameter(CaptureUnmatchedValues = true)]
    public Dictionary<string, object> Attrs { get; set; }

    private static readonly double Seconds = UserLoginCodeService.ExpirationTime.TotalSeconds;
    private double _seconds = Seconds;
    private string _data;
    private ApplicationUser _user;
    private Timer _timer;

    protected override async Task OnParametersSetAsync()
    {
        var auth = await AuthenticationStateProvider.GetAuthenticationStateAsync();
        var userId = auth.User.Identity?.IsAuthenticated is true
            ? auth.User.GetIdOrNull()
            : null;
        if (userId is null) return;
        var loggedInUser = await UserManager.FindByIdAsync(ImpersonatedUserId ?? userId);
        if (loggedInUser is null) return;
        if (await AuthorizationService.AuthorizeAsync(auth.User, loggedInUser.Id, [new PolicyRequirement(ImpersonationPlugin.CanImpersonateUser)]) is not { Succeeded: true })
            return;
        _user = loggedInUser;
        GenerateCodeAndStartTimer();
    }

    public void Dispose()
    {
        _timer?.Dispose();
    }

    private void GenerateCodeAndStartTimer()
    {
        var loginCode = UserLoginCodeService.Generate(_user.Id);
        _data = GetData(loginCode);
        _seconds = Seconds;
        _timer?.Dispose();
        _timer = new Timer(1000);
        _timer.Elapsed += CountDownTimer;
        _timer.Enabled = true;
    }

    private void CountDownTimer(object source, ElapsedEventArgs e)
    {
        if (_seconds > 0)
            _seconds -= 1;
        else
            GenerateCodeAndStartTimer();
        InvokeAsync(StateHasChanged);
    }

    private string GetData(string loginCode)
    {
        var req = HttpContextAccessor.HttpContext?.Request;
        if (req == null) return "";
        return LinkGenerator.LoginCodeLink(loginCode, RedirectUrl, req.GetRequestBaseUrl());
    }

    private double Percent => Math.Round(_seconds / Seconds * 100);
    private string CssClass => $"user-login-code d-inline-flex flex-column {(Attrs?.ContainsKey("class") is true ? Attrs["class"] : "")}".Trim();
}