// Ordre des trames à l'attache : régression de « le terminal reste tout noir alors que la session
// tourne ». Le replay d'attache est une frame BINAIRE ; le client n'apprend le numéro de canal
// qu'avec le message `attached`, et jette toute frame binaire portant un canal inconnu. Émettre le
// replay avant `attached` revenait donc à ne rien afficher jusqu'au prochain octet spontané du PTY,
// c'est-à-dire jamais pour un TUI au repos (Claude à son prompt).
//
// On instrumente la gateway avec un faux socket et de faux bus d'événements : c'est le seul moyen
// d'observer l'ORDRE réel des `socket.send` sans monter un vrai serveur WebSocket (couvert par
// scripts/acceptance-p17.mjs).
import { tmpdir } from 'node:os';
import { beforeEach, describe, expect, it, vi } from 'vitest';
import { BINARY_FRAME, decodeBinaryFrame, PROTOCOL_VERSION } from '@arboretum/shared';
import { registerWsGateway } from '../src/ws/gateway.js';
import { PtyManager } from '../src/core/pty-manager.js';
import { openDb, type Db } from '../src/db/index.js';

vi.mock('node:child_process', () => ({ execFileSync: () => '/usr/bin/claude\n' }));

const ptyMock = vi.hoisted(() => ({ instances: [] as unknown[] }));

vi.mock('@homebridge/node-pty-prebuilt-multiarch', () => {
  let nextPid = 200_000;
  class FakePtyImpl {
    pid = nextPid++;
    write = vi.fn();
    resize = vi.fn();
    pause = vi.fn();
    resume = vi.fn();
    kill = vi.fn();
    private dataCbs: Array<(d: string) => void> = [];
    constructor(
      readonly file: string,
      readonly args: string[],
      readonly opts: unknown,
    ) {}
    onData(cb: (d: string) => void): { dispose: () => void } {
      this.dataCbs.push(cb);
      return { dispose: () => {} };
    }
    onExit(): { dispose: () => void } {
      return { dispose: () => {} };
    }
    emitData(d: string): void {
      for (const cb of this.dataCbs) cb(d);
    }
  }
  return {
    default: {
      spawn: (file: string, args: string[], opts: unknown): FakePtyImpl => {
        const p = new FakePtyImpl(file, args, opts);
        ptyMock.instances.push(p);
        return p;
      },
    },
  };
});

/** Bus d'événements inerte : la gateway s'abonne à 7 services dont un seul nous intéresse. */
const inertBus = (): { on: () => void; off: () => void } => ({ on: () => {}, off: () => {} });

interface FakeSocket {
  readyState: number;
  OPEN: number;
  sent: Array<string | Uint8Array>;
  send(data: string | Uint8Array): void;
  on(event: string, cb: (...args: unknown[]) => void): void;
  ping(): void;
  terminate(): void;
  close(): void;
  emit(event: string, ...args: unknown[]): void;
}

function makeSocket(): FakeSocket {
  const handlers = new Map<string, Array<(...args: unknown[]) => void>>();
  return {
    readyState: 1,
    OPEN: 1,
    sent: [],
    send(data) {
      this.sent.push(data);
    },
    on(event, cb) {
      const list = handlers.get(event) ?? [];
      list.push(cb);
      handlers.set(event, list);
    },
    ping() {},
    terminate() {},
    close() {},
    emit(event, ...args) {
      for (const cb of handlers.get(event) ?? []) cb(...args);
    },
  };
}

describe('gateway · ordre des trames à l’attache', () => {
  let db: Db;
  let manager: PtyManager;
  let socket: FakeSocket;

  beforeEach(() => {
    ptyMock.instances.length = 0;
    db = openDb(':memory:');
    manager = new PtyManager(db);
    socket = makeSocket();

    let handler: ((s: unknown, req: unknown) => void) | null = null;
    const app = {
      get: (_path: string, _opts: unknown, h: (s: unknown, req: unknown) => void) => {
        handler = h;
      },
    };
    registerWsGateway(
      app as never,
      manager,
      inertBus() as never,
      inertBus() as never,
      inertBus() as never,
      inertBus() as never,
      inertBus() as never,
      inertBus() as never,
      '0.0.0-test',
    );
    handler!(socket, {});
    socket.emit('message', Buffer.from(JSON.stringify({ type: 'hello', protocol: PROTOCOL_VERSION })), false);
    socket.sent.length = 0; // on ignore le hello_ok
  });

  const send = (msg: unknown): void => socket.emit('message', Buffer.from(JSON.stringify(msg)), false);
  const texts = (): Array<Record<string, unknown>> =>
    socket.sent.filter((f): f is string => typeof f === 'string').map((f) => JSON.parse(f) as Record<string, unknown>);

  it('`attached` d’abord, replay binaire ENSUITE, sur le même canal', () => {
    const summary = manager.spawn({ cwd: tmpdir(), command: 'bash' });
    (ptyMock.instances.at(-1) as { emitData(d: string): void }).emitData('prompt$ ');

    send({ type: 'attach', sessionId: summary.id, mode: 'interactive', cols: 80, rows: 24 });

    expect(socket.sent).toHaveLength(2);
    const attached = JSON.parse(socket.sent[0] as string) as { type: string; channel: number };
    expect(attached.type).toBe('attached');

    const frame = decodeBinaryFrame(socket.sent[1] as Uint8Array);
    expect(frame.type).toBe(BINARY_FRAME.RESYNC);
    expect(frame.channel).toBe(attached.channel);
    expect(Buffer.from(frame.payload).toString()).toBe('prompt$ ');
  });

  it('ring vide : le resync part quand même (il porte l’ordre de reset)', () => {
    const summary = manager.spawn({ cwd: tmpdir(), command: 'bash' });
    send({ type: 'attach', sessionId: summary.id, mode: 'interactive', cols: 80, rows: 24 });

    expect(socket.sent).toHaveLength(2);
    const frame = decodeBinaryFrame(socket.sent[1] as Uint8Array);
    expect(frame.type).toBe(BINARY_FRAME.RESYNC);
    expect(frame.payload.byteLength).toBe(0);
  });

  it('attache sans écran : `attached` seul, aucune frame binaire', () => {
    const summary = manager.spawn({ cwd: tmpdir(), command: 'bash' });
    (ptyMock.instances.at(-1) as { emitData(d: string): void }).emitData('bruit');

    send({ type: 'attach', sessionId: summary.id, mode: 'interactive', cols: 120, rows: 32, screen: false });

    expect(texts().map((m) => m.type)).toEqual(['attached']);
    expect(socket.sent.every((f) => typeof f === 'string')).toBe(true);
    expect(texts()[0]).toMatchObject({ controlling: false });
  });

  it('un observer reçoit aussi son replay (il peint, lui)', () => {
    const summary = manager.spawn({ cwd: tmpdir(), command: 'bash' });
    (ptyMock.instances.at(-1) as { emitData(d: string): void }).emitData('ecran');

    send({ type: 'attach', sessionId: summary.id, mode: 'observer', cols: 80, rows: 24 });

    const frame = decodeBinaryFrame(socket.sent[1] as Uint8Array);
    expect(frame.type).toBe(BINARY_FRAME.RESYNC);
    expect(Buffer.from(frame.payload).toString()).toBe('ecran');
  });

  it('session introuvable : erreur seule, pas de canal ni de frame binaire', () => {
    send({ type: 'attach', sessionId: 'inconnue', mode: 'interactive', cols: 80, rows: 24 });
    expect(texts()).toEqual([{ type: 'error', code: 'NOT_FOUND', message: 'Cannot attach: NOT_FOUND' }]);
  });
});