using System.Net;
using System.Security.Claims;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Options;
using MxGateway.Server.Configuration;
using MxGateway.Server.Dashboard;
using MxGateway.Server.Security.Authorization;

namespace MxGateway.Tests.Gateway.Dashboard;

public sealed class DashboardAuthorizationHandlerTests
{
    /// <summary>Verifies that unauthenticated remote requests fail authorization.</summary>
    [Fact]
    public async Task HandleAsync_UnauthenticatedRemoteRequest_DoesNotSucceed()
    {
        AuthorizationHandlerContext context = await AuthorizeAsync(
            new ClaimsPrincipal(new ClaimsIdentity()),
            IPAddress.Parse("10.0.0.5"),
            allowAnonymousLocalhost: false);

        Assert.False(context.HasSucceeded);
    }

    /// <summary>Verifies that anonymous localhost access succeeds when allowed.</summary>
    [Fact]
    public async Task HandleAsync_AnonymousLocalhostAllowed_Succeeds()
    {
        AuthorizationHandlerContext context = await AuthorizeAsync(
            new ClaimsPrincipal(new ClaimsIdentity()),
            IPAddress.Loopback,
            allowAnonymousLocalhost: true);

        Assert.True(context.HasSucceeded);
    }

    /// <summary>Verifies that authenticated users without admin scope fail authorization.</summary>
    [Fact]
    public async Task HandleAsync_AuthenticatedWithoutAdminScope_DoesNotSucceed()
    {
        AuthorizationHandlerContext context = await AuthorizeAsync(
            CreatePrincipal(GatewayScopes.EventsRead),
            IPAddress.Loopback,
            allowAnonymousLocalhost: false);

        Assert.False(context.HasSucceeded);
    }

    /// <summary>Verifies that authenticated users with admin scope succeed.</summary>
    [Fact]
    public async Task HandleAsync_AuthenticatedWithAdminScope_Succeeds()
    {
        AuthorizationHandlerContext context = await AuthorizeAsync(
            CreatePrincipal(GatewayScopes.Admin),
            IPAddress.Parse("10.0.0.5"),
            allowAnonymousLocalhost: false);

        Assert.True(context.HasSucceeded);
    }

    private static async Task<AuthorizationHandlerContext> AuthorizeAsync(
        ClaimsPrincipal principal,
        IPAddress remoteAddress,
        bool allowAnonymousLocalhost)
    {
        DashboardAuthorizationRequirement requirement = new();
        DefaultHttpContext httpContext = new();
        httpContext.Connection.RemoteIpAddress = remoteAddress;
        DashboardAuthorizationHandler handler = new(
            new HttpContextAccessor { HttpContext = httpContext },
            Options.Create(new GatewayOptions
            {
                Dashboard = new DashboardOptions
                {
                    AllowAnonymousLocalhost = allowAnonymousLocalhost,
                    RequireAdminScope = true
                }
            }));
        AuthorizationHandlerContext context = new([requirement], principal, httpContext);

        await handler.HandleAsync(context);

        return context;
    }

    private static ClaimsPrincipal CreatePrincipal(string scope)
    {
        ClaimsIdentity identity = new(
            [new Claim(DashboardAuthenticationDefaults.ScopeClaimType, scope)],
            DashboardAuthenticationDefaults.AuthenticationScheme);

        return new ClaimsPrincipal(identity);
    }
}