using System.Security.Claims;
using Microsoft.AspNetCore.Http;
using ScadaLink.CentralUI.Auth;

namespace ScadaLink.CentralUI.Tests.Auth;

/// <summary>
/// Regression tests for CentralUI-004. The provider used to read
/// <see cref="IHttpContextAccessor.HttpContext"/> on every call; once the Blazor
/// circuit is established that context is gone, so later re-evaluations saw an
/// unauthenticated principal. The provider must snapshot the principal once at
/// construction (during the initial HTTP request) and serve it for the circuit.
/// </summary>
public class CookieAuthenticationStateProviderTests
{
    private static ClaimsPrincipal AuthenticatedUser(string name)
    {
        var identity = new ClaimsIdentity(
            new[] { new Claim(ClaimTypes.Name, name) },
            authenticationType: "TestCookie");
        return new ClaimsPrincipal(identity);
    }

    [Fact]
    public async Task GetAuthenticationStateAsync_ReturnsAuthenticatedUser_WhenHttpContextPresent()
    {
        var accessor = new HttpContextAccessor
        {
            HttpContext = new DefaultHttpContext { User = AuthenticatedUser("alice") }
        };

        var provider = new CookieAuthenticationStateProvider(accessor);
        var state = await provider.GetAuthenticationStateAsync();

        Assert.True(state.User.Identity?.IsAuthenticated);
        Assert.Equal("alice", state.User.Identity?.Name);
    }

    [Fact]
    public async Task GetAuthenticationStateAsync_StillReturnsUser_AfterHttpContextIsGone()
    {
        // The circuit is built during the HTTP request: HttpContext is valid then.
        var accessor = new HttpContextAccessor
        {
            HttpContext = new DefaultHttpContext { User = AuthenticatedUser("bob") }
        };
        var provider = new CookieAuthenticationStateProvider(accessor);

        // After the request completes, IHttpContextAccessor.HttpContext is null for
        // the life of the long-lived SignalR circuit.
        accessor.HttpContext = null;

        var state = await provider.GetAuthenticationStateAsync();

        // The pre-fix implementation returned an anonymous principal here.
        Assert.True(state.User.Identity?.IsAuthenticated);
        Assert.Equal("bob", state.User.Identity?.Name);
    }

    [Fact]
    public async Task GetAuthenticationStateAsync_IsStableAcrossCalls_IgnoringStaleForeignContext()
    {
        var accessor = new HttpContextAccessor
        {
            HttpContext = new DefaultHttpContext { User = AuthenticatedUser("carol") }
        };
        var provider = new CookieAuthenticationStateProvider(accessor);

        // A stale/foreign context leaking through the AsyncLocal accessor must NOT
        // change what this circuit's provider reports.
        accessor.HttpContext = new DefaultHttpContext { User = AuthenticatedUser("intruder") };

        var first = await provider.GetAuthenticationStateAsync();
        var second = await provider.GetAuthenticationStateAsync();

        Assert.Equal("carol", first.User.Identity?.Name);
        Assert.Equal("carol", second.User.Identity?.Name);
    }
}
