// Copyright 2026 Kingsrook, LLC
// SPDX-License-Identifier: Apache-2.0
using System.Net;
using System.Security.Authentication;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.RegularExpressions;
using Qqq.PrintAgent.Core.Authentication;
namespace Printing.NativeAuth;



/// <summary>Qualify real provider sessions only in the selected experimental environment.</summary>
internal static class Program
{
   private const string CoreSource = "ecf0f550a0357cec6387c2b54efca128a405a629";



   private const string ClientSource = "346fc285198908c47a2ee9db7b9adb53d5e88c3c";



   private const string InputPath = "/work/input.json";



   private const string ResultPath = "/work/result.json";



   private const string TlsMarker = "/tmp/printing-native-untrusted-tls-passed";



   private static readonly JsonSerializerOptions s_reportOptions = new() { WriteIndented = true };



   private static readonly List<string> s_checks = [];



   private static string s_stage = "input";



   private static bool? s_authorizationRequestMatches;



   /// <summary>Validate synthetic input and record bounded evidence without credential output.</summary>
   public static async Task<int> Main(string[] arguments)
   {
      if(arguments is ["--check-discovery"])
      {
         await NativeAuthDiscoveryChecks.RunAsync();
         return 0;
      }
      JsonObject? input = null;
      try
      {
         if(arguments.Length != 1 || arguments[0] is not ("assert-untrusted" or "test"))
         {
            throw new InvalidOperationException("An explicit fixture action is required.");
         }
         if(new FileInfo(InputPath).Length is <= 0 or > 65536)
         {
            throw new InvalidOperationException("Fixture input size is invalid.");
         }
         input = JsonNode.Parse(await File.ReadAllTextAsync(InputPath))!.AsObject();
         ValidateInput(input);
         using var deadline = new CancellationTokenSource(TimeSpan.FromMinutes(5));
         if(string.Equals(arguments[0], "assert-untrusted", StringComparison.Ordinal))
         {
            s_stage = "untrusted-tls";
            await AssertUntrustedAsync(new Uri(ProviderSetup.Text(input, "providerOrigin")), deadline.Token);
            await File.WriteAllTextAsync(TlsMarker, "passed", deadline.Token);
            return 0;
         }
         if(!File.Exists(TlsMarker))
         {
            throw new InvalidOperationException("The ordinary TLS negative control did not run.");
         }
         s_checks.Add("untrusted-tls-refused");
         await QualifyAsync(input, deadline.Token);
         await WriteResultAsync(input, "PASS", null, null);
         Console.WriteLine("Experimental native Authentik qualification passed; development-only unpublished core.");
         return 0;
      }
      catch(Exception exception)
      {
         // Exception messages, response bodies, callback URLs and credentials are deliberately withheld.
         await WriteResultAsync(input, "FAILED", exception.GetType().Name,
            exception is QqqSessionException sessionException ? sessionException.Failure.ToString() : null);
         Console.Error.WriteLine("Experimental native Authentik qualification failed at " + s_stage + " (" + exception.GetType().Name + ").");
         return 1;
      }
   }



   /// <summary>Refuse fixture identities, origins, or source tuples outside the pinned contract.</summary>
   private static void ValidateInput(JsonObject input)
   {
      if(!Regex.IsMatch(ProviderSetup.Text(input, "project"), "^qbit-printing-dev-[a-f0-9]{32}$", RegexOptions.CultureInvariant | RegexOptions.NonBacktracking)
            || !string.Equals(ProviderSetup.Text(input, "coreSource"), CoreSource, StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "clientSource"), ClientSource, StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "providerOrigin"), "https://auth.printing.internal", StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "qqqOrigin"), "https://qqq.printing.internal", StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "callback"), "https://callback.printing.internal/oauth/callback", StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "issuer"), "https://auth.printing.internal/application/o/" + ProviderSetup.Text(input, "project") + "/", StringComparison.Ordinal)
            || !string.Equals(ProviderSetup.Text(input, "clientId"), ProviderSetup.Text(input, "project"), StringComparison.Ordinal))
      {
         throw new InvalidOperationException("Fixture identity or destination differs from the pinned local contract.");
      }
   }



   /// <summary>Create the production session client with redirects, cookies, and proxies controlled.</summary>
   private static QqqSessionClient Session(Uri origin) => new(origin,
      new HttpClientHandler { AllowAutoRedirect = false, UseCookies = false, UseProxy = false });



   /// <summary>Require TLS to reject the private CA before scoped trust is installed.</summary>
   private static async Task AssertUntrustedAsync(Uri origin, CancellationToken token)
   {
      using var transport = new FixtureHttp(origin);
      try
      {
         await transport.SendAsync("GET", "/-/health/live/", null, token);
      }
      catch(HttpRequestException exception)
      {
         for(Exception? cause = exception; cause is not null; cause = cause.InnerException)
         {
            if(cause is AuthenticationException)
            {
               return;
            }
         }
         throw new InvalidOperationException("The negative TLS control failed for a reason other than certificate authentication.", exception);
      }
      throw new InvalidOperationException("The test unexpectedly trusted its private CA before scoped installation.");
   }



   /// <summary>Exercise real discovery, authorization, origin enforcement, logout, renewal, and revocation.</summary>
   private static async Task QualifyAsync(JsonObject input, CancellationToken token)
   {
      var origin = new Uri(ProviderSetup.Text(input, "qqqOrigin"));
      var providerOrigin = new Uri(ProviderSetup.Text(input, "providerOrigin"));
      var callback = new Uri(ProviderSetup.Text(input, "callback"));
      s_stage = "readiness";
      await WaitForQqqAsync(origin, token);
      using var provider = new ProviderSetup(input);
      s_stage = "provider-readiness";
      await provider.WaitReadyAsync(token);
      s_stage = "provider-configuration";
      await provider.ConfigureAsync(token);
      using var receiver = new CallbackReceiver(callback);
      using QqqSessionClient first = Session(origin);
      s_stage = "typed-native-discovery";
      await NativeAuthDiscovery.DiscoverAsync(first, token);
      QqqAuthenticationMetadata metadata = await first.GetAuthenticationMetadataAsync(token);
      if(!string.Equals(metadata.Values?.ClientId, ProviderSetup.Text(input, "clientId"), StringComparison.Ordinal))
      {
         throw new InvalidOperationException("Native metadata did not retain the configured client identifier.");
      }
      s_checks.Add("typed-native-grant");
      s_stage = "real-provider-login";
      await LoginAsync(first, receiver, input, providerOrigin, callback, authorized: true, token);
      s_stage = "authorized-native-identity";
      QqqSessionBinding identity = await first.GetSessionIdentityAsync(token);
      if(string.IsNullOrWhiteSpace(identity.PrincipalId) || !string.Equals(identity.TenantId, "printing-native-dev", StringComparison.Ordinal) || identity.DeviceId is not null)
      {
         throw new InvalidOperationException("The native subject did not receive the intended server-derived identity.");
      }
      s_checks.Add("real-provider-login");
      s_stage = "wrong-origin-cookie";
      await AssertWrongOriginAsync(origin, first.ExportCredential(), token);
      await first.GetSessionIdentityAsync(token);
      s_checks.Add("wrong-origin-cookie-denied");
      s_stage = "permission-denied-user";
      using(QqqSessionClient denied = Session(origin))
      {
         await LoginAsync(denied, receiver, input, providerOrigin, callback, authorized: false, token);
         await ExpectFailureAsync(() => denied.GetSessionIdentityAsync(token), QqqSessionException.FailureKind.PermissionDenied);
         await denied.SignOutAsync(token);
      }
      s_checks.Add("permission-denied-user");
      await AssertLogoutReplayAsync(first, origin, token);
      await QualifyRenewalAsync(input, provider, receiver, origin, providerOrigin, callback, token);
   }



   /// <summary>Verify that signing out invalidates the exact previously exported native cookie.</summary>
   private static async Task AssertLogoutReplayAsync(QqqSessionClient first, Uri origin, CancellationToken token)
   {
      s_stage = "logout-replay";
      QqqSessionCredential retired = first.ExportCredential();
      await first.SignOutAsync(token);
      using(QqqSessionClient replay = Session(origin))
      {
         await ExpectFailureAsync(() => replay.RestoreSessionAsync(retired, token), QqqSessionException.FailureKind.AuthenticationRequired);
      }
      s_checks.Add("logout-replay-denied");
   }



   /// <summary>Cross real provider expiry and revocation while preserving the authenticated subject.</summary>
   private static async Task QualifyRenewalAsync(JsonObject input, ProviderSetup provider, CallbackReceiver receiver,
      Uri origin, Uri providerOrigin, Uri callback, CancellationToken token)
   {
      s_stage = "fresh-login-for-renewal";
      using QqqSessionClient renewable = Session(origin);
      await LoginAsync(renewable, receiver, input, providerOrigin, callback, authorized: true, token);
      QqqSessionBinding before = await renewable.GetSessionIdentityAsync(token);
      HashSet<string> previousGrants = await provider.AccessGrantIdsAsync(token);
      s_stage = "server-refresh-after-expiry";
      await Task.Delay(TimeSpan.FromSeconds(22), token);
      await renewable.ResumeSessionAsync(token);
      QqqSessionBinding after = await renewable.GetSessionIdentityAsync(token);
      HashSet<string> refreshedGrants = await provider.AccessGrantIdsAsync(token);
      if(before != after || !refreshedGrants.Except(previousGrants, StringComparer.Ordinal).Any())
      {
         throw new InvalidOperationException("Renewal did not preserve the identity and obtain a new actual provider grant.");
      }
      s_checks.Add("server-refresh-after-expiry");
      s_stage = "provider-revocation-after-expiry";
      await provider.RevokeRefreshGrantsAsync(token);
      await Task.Delay(TimeSpan.FromSeconds(22), token);
      await ExpectFailureAsync(() => renewable.ResumeSessionAsync(token), QqqSessionException.FailureKind.AuthenticationRequired);
      s_checks.Add("provider-revocation-denied");
      s_stage = "complete";
   }



   /// <summary>Use the real PKCE attempt and provider callback without synthesizing identity.</summary>
   private static async Task LoginAsync(QqqSessionClient client, CallbackReceiver receiver, JsonObject input,
      Uri providerOrigin, Uri callback, bool authorized, CancellationToken token)
   {
      string role = authorized ? "authorized" : "denied";
      s_stage = role + "-begin-pkce";
      QqqBrowserLogin attempt = await client.BeginBrowserLoginAsync(callback, token);
      s_stage = role + "-generated-authorization-request";
      var parameters = attempt.AuthorizationUri.Query.TrimStart('?').Split('&')
         .Select(entry => entry.Split('=', 2)).ToDictionary(pair => Uri.UnescapeDataString(pair[0]), pair => Uri.UnescapeDataString(pair[1]), StringComparer.Ordinal);
      s_authorizationRequestMatches = string.Equals(attempt.AuthorizationUri.AbsolutePath, "/application/o/authorize/", StringComparison.Ordinal)
         && string.Equals(parameters.GetValueOrDefault("client_id"), ProviderSetup.Text(input, "clientId"), StringComparison.Ordinal)
         && string.Equals(parameters.GetValueOrDefault("redirect_uri"), callback.AbsoluteUri, StringComparison.Ordinal)
         && string.Equals(parameters.GetValueOrDefault("response_type"), "code", StringComparison.Ordinal)
         && string.Equals(parameters.GetValueOrDefault("code_challenge_method"), "S256", StringComparison.Ordinal)
         && parameters.GetValueOrDefault("state")?.Length == 43;
      if(s_authorizationRequestMatches != true)
      {
         throw new InvalidOperationException("The generated authorization request differs from the exact provider registration.");
      }
      s_stage = role + "-provider-flow";
      await ProviderFlow.AuthenticateAsync(attempt.AuthorizationUri, providerOrigin, callback,
         ProviderSetup.Text(input, role + "Username"), ProviderSetup.Text(input, role + "Password"), token);
      s_stage = role + "-callback";
      Uri actualCallback = await receiver.ReadAsync(token);
      s_stage = role + "-exchange";
      await client.CompleteBrowserLoginAsync(attempt, actualCallback, token);
   }



   /// <summary>Require the precise native authentication or permission failure.</summary>
   private static async Task ExpectFailureAsync(Func<Task> operation, QqqSessionException.FailureKind expected)
   {
      try
      {
         await operation();
      }
      catch(QqqSessionException exception) when(exception.Failure == expected) { return; }
      throw new InvalidOperationException("The expected native authentication or permission denial did not occur.");
   }



   /// <summary>Verify the authenticated native boundary rejects a foreign Origin.</summary>
   private static async Task AssertWrongOriginAsync(Uri origin, QqqSessionCredential credential, CancellationToken token)
   {
      using var http = new HttpClient(new HttpClientHandler { AllowAutoRedirect = false, UseCookies = false, UseProxy = false })
      {
         Timeout = TimeSpan.FromSeconds(15),
         MaxResponseContentBufferSize = 65536
      };
      using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(origin, "/qqq/v1/qbit/printing/session"));
      request.Headers.Add("X-QQQ-Client", QqqSessionClient.ClientChannel);
      request.Headers.Add("Cookie", "sessionUUID=" + credential.SessionToken);
      request.Headers.Add("Origin", "https://wrong-origin.invalid");
      using HttpResponseMessage response = await http.SendAsync(request, token);
      if(response.StatusCode != HttpStatusCode.Forbidden)
      {
         throw new InvalidOperationException("The fixture did not reject a wrong-Origin cookie request.");
      }
   }



   /// <summary>Bound startup readiness reads to the owned QQQ host.</summary>
   private static async Task WaitForQqqAsync(Uri origin, CancellationToken token)
   {
      using var http = new FixtureHttp(origin);
      for(int attempt = 0; attempt < 45; attempt++)
      {
         try
         {
            FixtureHttp.Reply response = await http.SendAsync("GET", "/qqq/v1/version", null, token);
            if(response.Status == HttpStatusCode.OK && response.Json is not null)
            {
               return;
            }
         }
         catch(HttpRequestException)
         {
            // The owned host is still starting; the bounded attempt loop retries and then fails explicitly.
         }
         await Task.Delay(TimeSpan.FromSeconds(2), token);
      }
      throw new InvalidOperationException("The owned native host did not become ready.");
   }



   /// <summary>Write only allowlisted classifications and results to the private report.</summary>
   private static Task WriteResultAsync(JsonObject? input, string status, string? failureType, string? sessionFailure)
      => File.WriteAllTextAsync(ResultPath, JsonSerializer.Serialize(new
      {
         status,
         scope = "DEVELOPMENT_ONLY_UNRELEASED",
         coreSource = CoreSource,
         clientSource = ClientSource,
         project = input?["project"]?.ToString(),
         observedUtc = DateTimeOffset.UtcNow,
         stage = s_stage,
         failureType,
         sessionFailure,
         lastRequestKind = FixtureHttp.LastRequestKind,
         lastHttpStatus = FixtureHttp.LastStatus,
         lastProviderComponent = ProviderFlow.LastComponent,
         authorizationRequestMatches = s_authorizationRequestMatches,
         requestClassifications = FixtureHttp.Trace,
         providerLookupKind = ProviderSetup.LastLookupKind,
         providerLookupCount = ProviderSetup.LastLookupCount,
         providerReadinessCounts = ProviderSetup.ReadinessCounts,
         checks = s_checks,
         installedUiAcceptance = false,
         providerRefreshTokensInClient = false,
      }, s_reportOptions));
}