using System.Text;
using Bff.Api;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.IdentityModel.Protocols.OpenIdConnect;
using Microsoft.IdentityModel.Tokens;

namespace Bff.Tests;

/// <summary>
/// Test host for the BFF. It swaps the downstream clients for in-memory fakes and reconfigures the
/// JWT bearer to validate against a local test key (no live Keycloak) — so token validation is
/// exercised in-process with tokens the tests mint (ADR-0010).
/// </summary>
internal sealed class BffFactory : WebApplicationFactory<Program>
{
    public static readonly SymmetricSecurityKey TestSigningKey =
        new(Encoding.UTF8.GetBytes("bff-test-signing-key-that-is-at-least-256-bits-long!"));

    public FakeDomainClient Domain { get; } = new();
    public FakeProjectionClient Projection { get; } = new();

    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.UseSetting("Keycloak:Authority", "https://keycloak.invalid/realms/digid");
        builder.UseSetting("Downstream:Domain:BaseUrl", "http://domain.invalid/");
        builder.UseSetting("Downstream:Projection:BaseUrl", "http://projection.invalid/");

        builder.ConfigureTestServices(services =>
        {
            services.AddSingleton<IDomainClient>(Domain);
            services.AddSingleton<IProjectionClient>(Projection);

            services.Configure<JwtBearerOptions>(JwtBearerDefaults.AuthenticationScheme, options =>
            {
                // Validate locally against the test key; never reach out for OIDC metadata.
                options.Authority = null;
                options.MetadataAddress = null!;
                options.RequireHttpsMetadata = false;
                options.Configuration = new OpenIdConnectConfiguration();
                options.TokenValidationParameters = new TokenValidationParameters
                {
                    ValidateIssuer = false,
                    ValidateAudience = false,
                    ValidateLifetime = true,
                    ValidateIssuerSigningKey = true,
                    IssuerSigningKey = TestSigningKey,
                    ClockSkew = TimeSpan.Zero,
                };
            });
        });
    }
}

/// <summary>Captures the bsn the BFF forwarded and returns a canned acceptance.</summary>
internal sealed class FakeDomainClient : IDomainClient
{
    public string? SubmittedBsn { get; private set; }
    public SubmitAccepted Result { get; set; } = new("reg-123", "Ingediend");

    public Task<SubmitAccepted> SubmitRegistrationAsync(string bsn, CancellationToken ct = default)
    {
        SubmittedBsn = bsn;
        return Task.FromResult(Result);
    }
}

/// <summary>Serves a configurable set of projection rows.</summary>
internal sealed class FakeProjectionClient : IProjectionClient
{
    public List<ProjectionEntry> Entries { get; } = [];

    public Task<IReadOnlyList<ProjectionEntry>> GetRegisterAsync(CancellationToken ct = default)
        => Task.FromResult<IReadOnlyList<ProjectionEntry>>(Entries);
}