import {
  describe,
  it,
  expect
} from 'vitest';
import {
  ProvisionUsernameCollisionError,
  buildProvisionPlan,
  buildProvisionUsernameCandidates,
  shortHomeUserId,
  shouldAdoptCanonicalSecret
} from './signal-server-provision.rules';

const HOME_USER_ID = 'a3f2b1c4-5678-90ab-cdef-1234567890ab';

function plan(canonical: string | null, deviceLocal: string | null) {
  return buildProvisionPlan({
    preferredUsername: 'alice',
    homeUserId: HOME_USER_ID,
    secrets: { canonical, deviceLocal }
  }).map((attempt) => `${attempt.kind}:${attempt.username}:${attempt.secretSource}`);
}

describe('signal-server-provision.rules', () => {
  it('derives a stable short id from a home user uuid', () => {
    expect(shortHomeUserId('a3f2b1c4-5678-90ab-cdef-1234567890ab')).toBe('a3f2b1');
  });

  it('orders username candidates with preferred first then suffixed fallback', () => {
    expect(
      buildProvisionUsernameCandidates('alice', 'a3f2b1c4-5678-90ab-cdef-1234567890ab')
    ).toEqual(['alice', 'alice-a3f2b1']);
  });

  it('deduplicates candidates when suffix would repeat preferred username', () => {
    expect(
      buildProvisionUsernameCandidates('alice-a3f2b1', 'a3f2b1c4-5678-90ab-cdef-1234567890ab')
    ).toEqual(['alice-a3f2b1']);
  });

  it('signs in to the preferred username before ever trying the suffixed one', () => {
    expect(plan('canonical-secret', null)).toEqual([
      'register:alice:canonical',
      'login:alice:canonical',
      'register:alice-a3f2b1:canonical',
      'login:alice-a3f2b1:canonical'
    ]);
  });

  it('tries the legacy device secret before giving the username up as someone else\'s', () => {
    expect(plan('canonical-secret', 'legacy-secret')).toEqual([
      'register:alice:canonical',
      'login:alice:canonical',
      'login:alice:device-local',
      'register:alice-a3f2b1:canonical',
      'login:alice-a3f2b1:canonical',
      'login:alice-a3f2b1:device-local'
    ]);
  });

  it('never registers a suffixed duplicate without a canonical secret', () => {
    expect(plan(null, 'legacy-secret')).toEqual([
      'register:alice:device-local',
      'login:alice:device-local',
      'login:alice-a3f2b1:device-local'
    ]);
  });

  it('produces no attempts when no secret is available at all', () => {
    expect(plan(null, null)).toEqual([]);
  });

  it('does not repeat the canonical secret as a legacy attempt', () => {
    expect(plan('same-secret', 'same-secret')).toEqual([
      'register:alice:canonical',
      'login:alice:canonical',
      'register:alice-a3f2b1:canonical',
      'login:alice-a3f2b1:canonical'
    ]);
  });

  it('adopts the canonical secret only after a legacy login', () => {
    expect(shouldAdoptCanonicalSecret({ kind: 'login', secretSource: 'device-local' }, 'canonical')).toBe(true);
    expect(shouldAdoptCanonicalSecret({ kind: 'login', secretSource: 'canonical' }, 'canonical')).toBe(false);
    expect(shouldAdoptCanonicalSecret({ kind: 'register', secretSource: 'device-local' }, 'canonical')).toBe(false);
    expect(shouldAdoptCanonicalSecret({ kind: 'login', secretSource: 'device-local' }, null)).toBe(false);
  });

  it('exposes attempted usernames on collision errors', () => {
    const error = new ProvisionUsernameCollisionError('https://signal.example.com', ['alice', 'alice-a3f2b1']);

    expect(error.name).toBe('ProvisionUsernameCollisionError');
    expect(error.serverUrl).toBe('https://signal.example.com');
    expect(error.attemptedUsernames).toEqual(['alice', 'alice-a3f2b1']);
  });
});