CannedNet/CannedNet.Admin/Components/Pages/Login.razor

@page "/login"
@rendermode InteractiveServer
@inject NavigationManager Navigation

<PageTitle>Login</PageTitle>

<div class="row justify-content-center mt-5">
    <div class="col-md-4">
        <div class="card">
            <div class="card-header"><h4 class="mb-0">Admin Login</h4></div>
            <div class="card-body">
                <form method="post" action="/admin/login">
                    @if (errorMessage != null)
                    {
                        <div class="alert alert-danger">@errorMessage</div>
                    }
                    <div class="mb-3">
                        <label class="form-label">Username</label>
                        <input type="text" name="username" class="form-control" required />
                    </div>
                    <div class="mb-3">
                        <label class="form-label">Password</label>
                        <input type="password" name="password" class="form-control" required />
                    </div>
                    <button type="submit" class="btn btn-primary w-100">Login</button>
                </form>
            </div>
        </div>
    </div>
</div>

@code {
    private string? errorMessage;

    protected override void OnInitialized()
    {
        var uri = new Uri(Navigation.Uri);
        var query = Microsoft.AspNetCore.WebUtilities.QueryHelpers.ParseQuery(uri.Query);
        var error = query.TryGetValue("error", out var val) ? val.FirstOrDefault() : null;
        errorMessage = error switch
        {
            "invalid" => "Invalid username or password.",
            "missing" => "Please enter both username and password.",
            "expired" => "Your session has expired. Please log in again.",
            _ => null
        };
    }
}