import 'package:flutter_test/flutter_test.dart';
import 'package:friendly_map/modules/keys/keys.dart';

Future<List<int>> deriverFor(int seed) async => List<int>.generate(32, (i) => (i + seed) % 256);

Future<IdentityKeys> keysOf(int seed) async => IdentityKeys((label) async {
      final base = await deriverFor(seed);
      return [...base.take(31), label.length % 256];
    });

void main() {
  test('같은 기본 비밀이면 같은 공개 키, 다르면 다른 공개 키', () async {
    final a1 = LocalIdentityProvider(await keysOf(1));
    final a2 = LocalIdentityProvider(await keysOf(1));
    final b = LocalIdentityProvider(await keysOf(2));
    expect(await a1.myPublicKey(), await a2.myPublicKey());
    expect(await a1.myPublicKey() == await b.myPublicKey(), false);
  });

  test('둘만 아는 키: 서로 잠근 것을 서로 풀 수 있다', () async {
    final ka = await keysOf(1), kb = await keysOf(2);
    final pubA = await LocalIdentityProvider(ka).myPublicKey();
    final pubB = await LocalIdentityProvider(kb).myPublicKey();
    final a = SharedPayloadCipher(ka), b = SharedPayloadCipher(kb);
    final sealed = await a.seal(plain: '안녕 😀', peerPublicKey: pubB, context: 'room1');
    expect(sealed.contains('안녕'), false);
    expect(await b.open(sealed: sealed, peerPublicKey: pubA, context: 'room1'), '안녕 😀');
    final back = await b.seal(plain: '답', peerPublicKey: pubA, context: 'room1');
    expect(await a.open(sealed: back, peerPublicKey: pubB, context: 'room1'), '답');
  });

  test('단위(대화방)가 다르면 풀리지 않는다', () async {
    final ka = await keysOf(1), kb = await keysOf(2);
    final pubA = await LocalIdentityProvider(ka).myPublicKey();
    final pubB = await LocalIdentityProvider(kb).myPublicKey();
    final sealed = await SharedPayloadCipher(ka).seal(plain: 'x', peerPublicKey: pubB, context: 'room1');
    expect(await SharedPayloadCipher(kb).open(sealed: sealed, peerPublicKey: pubA, context: 'room2'), null);
  });

  test('제3자는 풀지 못하고, 중간에 바뀐 내용은 거절', () async {
    final ka = await keysOf(1), kb = await keysOf(2), kc = await keysOf(3);
    final pubA = await LocalIdentityProvider(ka).myPublicKey();
    final pubB = await LocalIdentityProvider(kb).myPublicKey();
    final sealed = await SharedPayloadCipher(ka).seal(plain: 'x', peerPublicKey: pubB, context: 'r');
    expect(await SharedPayloadCipher(kc).open(sealed: sealed, peerPublicKey: pubA, context: 'r'), null);
    final tampered = '${sealed.substring(0, sealed.length - 4)}AAAA';
    expect(await SharedPayloadCipher(kb).open(sealed: tampered, peerPublicKey: pubA, context: 'r'), null);
    expect(await SharedPayloadCipher(kb).open(sealed: 'not base64!!', peerPublicKey: pubA, context: 'r'), null);
  });
}