WorkTracker/Components/Pages/Login.razor

@page "/login"
@attribute [AllowAnonymous]

@using Microsoft.AspNetCore.Authorization
@using Microsoft.AspNetCore.Components
@using Microsoft.Extensions.Options
@using WorkTracker.Configuration

@inject IOptions<AppAuthOptions> AppAuthOptions
@inject NavigationManager Navigation

<PageTitle>Login</PageTitle>

@if (!AppAuthOptions.Value.Enabled)
{
    <p>Redirecting...</p>
}
else
{
<h1>Login</h1>

@if (!string.IsNullOrWhiteSpace(Error))
{
    <div class="alert alert-danger" role="alert">@Error</div>
}

<form method="post" action="/api/login" class="d-flex flex-column gap-3" style="max-width: 420px;">
    <div>
        <label for="username" class="form-label">Username</label>
        <input id="username" name="username" value="@Username" autocomplete="username" class="form-control" required />
    </div>

    <div>
        <label for="password" class="form-label">Password</label>
        <input id="password" name="password" type="password" autocomplete="current-password" class="form-control" required />
    </div>

    <input type="hidden" name="returnUrl" value="@SafeReturnUrl" />

    <button type="submit" class="btn btn-primary">Sign in</button>
</form>
}

@code {
    [SupplyParameterFromQuery]
    public string? ReturnUrl { get; set; }

    [SupplyParameterFromQuery]
    public string? Error { get; set; }

    [SupplyParameterFromQuery]
    public string? Username { get; set; }

    protected override void OnInitialized()
    {
        if (!AppAuthOptions.Value.Enabled)
        {
            Navigation.NavigateTo(SafeReturnUrl, forceLoad: true);
        }
    }

    private string SafeReturnUrl =>
        string.IsNullOrWhiteSpace(ReturnUrl) || !Uri.IsWellFormedUriString(ReturnUrl, UriKind.Relative)
            ? "/"
            : ReturnUrl;
}