stack/apps/gateway/src/chat/chat.gateway-redaction.spec.ts

import { describe, expect, it, vi } from 'vitest';
import { ChatGateway } from './chat.gateway.js';

const CONVERSATION_ID = 'conversation-1';
const CANARY = 'sk_canary12345678';

/**
 * Task 5 fence (F, GREEN control): the redaction boundary is pre-Task-5 egress/persistence
 * functionality, orthogonal to runtime routing — it must keep holding unchanged across Task 5.
 * After Step Three, `relayEvent` consumes normalized {@link LegacyRuntimeEvent}s and never reads
 * the runtime slot, a pi session, or records usage: the runtime owns all session/token
 * bookkeeping and hands finished usage back on the `settled` event. So this control fronts slot0
 * with a bare, getSession-less stub — proving the redaction path is independent of the runtime —
 * and drives the gateway with the normalized event vocabulary (`text_delta` / `settled`).
 */
function clientConversationKey(clientId: string, conversationId: string): string {
  return `${clientId}${conversationId}`;
}

type GatewayInternals = {
  clientSessions: Map<string, unknown>;
  relayEvent(client: unknown, conversationId: string, event: unknown): void;
};

function buildGateway() {
  const brain = {
    conversations: {
      addMessage: vi.fn().mockResolvedValue(undefined),
    },
  };
  // slot0 is the ChatRuntimeRouter in production; relayEvent never touches it, so a bare stub
  // with no getSession proves the redaction boundary is orthogonal to runtime routing.
  const runtime = {};
  const gateway = new ChatGateway(
    runtime as never,
    {} as never,
    brain as never,
    {} as never,
    {} as never,
    {} as never,
  );

  return { gateway: gateway as unknown as GatewayInternals, brain };
}

describe('ChatGateway redaction boundary', (): void => {
  it('redacts a secret split across assistant deltas before egress and persistence', (): void => {
    const { gateway } = buildGateway();
    const client = {
      connected: true,
      id: 'client-1',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };
    const session = {
      clientId: client.id,
      conversationId: CONVERSATION_ID,
      assistantText: '',
      toolCalls: [],
      pendingToolCalls: new Map(),
      scope: { userId: 'user-1', tenantId: 'tenant-1' },
    };
    gateway.clientSessions.set(clientConversationKey(client.id, CONVERSATION_ID), session);

    gateway.relayEvent(client, CONVERSATION_ID, { type: 'text_delta', text: 'sk_canary' });

    expect(JSON.stringify(client.emit.mock.calls)).not.toContain('sk_canary');

    gateway.relayEvent(client, CONVERSATION_ID, { type: 'text_delta', text: '12345678 ' });

    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: CONVERSATION_ID,
      text: '[REDACTED_SECRET] ',
    });
    expect(session.assistantText).toBe(`${CANARY} `);
    expect(JSON.stringify(client.emit.mock.calls)).not.toContain(CANARY);
  });

  it('retains a split secret label until its value can be redacted', (): void => {
    const { gateway } = buildGateway();
    const client = {
      connected: true,
      id: 'client-1',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };

    gateway.relayEvent(client, CONVERSATION_ID, { type: 'text_delta', text: 'token ' });
    gateway.relayEvent(client, CONVERSATION_ID, { type: 'text_delta', text: '=canaryvalue123 ' });

    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: CONVERSATION_ID,
      text: '[REDACTED_SECRET] ',
    });
    expect(JSON.stringify(client.emit.mock.calls)).not.toContain('canaryvalue123');
  });

  it('holds a streamed private key until it can be redacted', (): void => {
    const { gateway } = buildGateway();
    const client = {
      connected: true,
      id: 'client-1',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };

    gateway.relayEvent(client, CONVERSATION_ID, {
      type: 'text_delta',
      text: '-----BEGIN PRIVATE KEY-----\ncanary',
    });
    gateway.relayEvent(client, CONVERSATION_ID, {
      type: 'text_delta',
      text: '\n-----END PRIVATE KEY-----',
    });

    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: CONVERSATION_ID,
      text: '[REDACTED_SECRET]',
    });
    expect(JSON.stringify(client.emit.mock.calls)).not.toContain('canary');
  });

  it('drops an oversized unterminated stream fragment rather than retaining it', (): void => {
    const { gateway } = buildGateway();
    const client = {
      connected: true,
      id: 'client-1',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };

    gateway.relayEvent(client, CONVERSATION_ID, { type: 'text_delta', text: 'x'.repeat(8_193) });

    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: CONVERSATION_ID,
      text: '[REDACTED_STREAM_OVERFLOW]',
    });
  });

  it('isolates concurrent conversation streams sharing one Discord socket', (): void => {
    const { gateway } = buildGateway();
    const client = {
      connected: true,
      id: 'discord-client',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };
    const firstConversation = 'Nova:discord:thread-1';
    const secondConversation = 'Nova:discord:thread-2';
    const createSession = (conversationId: string) => ({
      clientId: client.id,
      conversationId,
      assistantText: '',
      toolCalls: [],
      pendingToolCalls: new Map(),
      scope: { userId: 'user-1', tenantId: 'tenant-1' },
    });
    const firstSession = createSession(firstConversation);
    const secondSession = createSession(secondConversation);
    gateway.clientSessions.set(clientConversationKey(client.id, firstConversation), firstSession);
    gateway.clientSessions.set(clientConversationKey(client.id, secondConversation), secondSession);

    gateway.relayEvent(client, firstConversation, {
      type: 'text_delta',
      text: 'first response ',
    });
    gateway.relayEvent(client, secondConversation, {
      type: 'text_delta',
      text: 'second response ',
    });

    expect(firstSession.assistantText).toBe('first response ');
    expect(secondSession.assistantText).toBe('second response ');
    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: firstConversation,
      text: 'first response ',
    });
    expect(client.emit).toHaveBeenCalledWith('agent:text', {
      conversationId: secondConversation,
      text: 'second response ',
    });
  });

  it('persists only redacted assistant content with classifications', (): void => {
    const { gateway, brain } = buildGateway();
    const client = {
      connected: true,
      id: 'client-1',
      data: { user: { id: 'user-1' } },
      emit: vi.fn(),
    };
    gateway.clientSessions.set(clientConversationKey(client.id, CONVERSATION_ID), {
      clientId: client.id,
      conversationId: CONVERSATION_ID,
      assistantText: CANARY,
      toolCalls: [],
      pendingToolCalls: new Map(),
      scope: { userId: 'user-1', tenantId: 'tenant-1' },
    });

    gateway.relayEvent(client, CONVERSATION_ID, { type: 'settled' });

    expect(brain.conversations.addMessage).toHaveBeenCalledWith(
      expect.objectContaining({
        content: '[REDACTED_SECRET]',
        metadata: expect.objectContaining({ classifications: ['secret'] }),
      }),
      'user-1',
    );
    expect(JSON.stringify(brain.conversations.addMessage.mock.calls)).not.toContain(CANARY);
  });
});