import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:halkyon_app/halkyon_app.dart';
import 'package:halkyon_app/testing.dart';
import 'package:halkyon_oidc_flutter/halkyon_oidc_flutter.dart';

/// A state at [step], [busy] or not, with [problem] or none.
Matcher at(SimpleLoginStep step, {bool busy = false, Exception? problem}) =>
    isA<SimpleLoginState>()
        .having((state) => state.step, 'step', step)
        .having((state) => state.busy, 'busy', busy)
        .having((state) => state.problem, 'problem', problem);

const password = 'correct horse battery';

void main() {
  late FakeAuthGateway auth;
  late FakeSimpleLoginGateway gateway;
  late FakeOidcBrowser browser;
  late FakeAccountCrypto crypto;
  late MemoryAccountKeyStore keys;
  late SimpleLoginRepository simpleLogin;

  setUp(() {
    auth = FakeAuthGateway();
    gateway = FakeSimpleLoginGateway(auth);
    browser = FakeOidcBrowser();
    crypto = FakeAccountCrypto();
    keys = MemoryAccountKeyStore();
    simpleLogin = SimpleLoginRepository(
      gateway,
      browser,
      crypto,
      keys,
      auth,
      callbackScheme: 'app.halkyon.test',
      loopbackPort: 43823,
      platform: TargetPlatform.android,
    );
  });

  SimpleLoginCubit cubitFor({bool link = false}) {
    final cubit = SimpleLoginCubit(simpleLogin, link: link);
    addTearDown(cubit.close);
    return cubit;
  }

  /// The words the check asks for, typed back right.
  List<String> wordsAsked(SimpleLoginState state) => [
    for (final position in state.checked) wordsOf(state.phrase)[position],
  ];

  /// Makes the keys with [password] and types the phrase back.
  Future<void> makeKeys(SimpleLoginCubit cubit) async {
    await cubit.passwordEntered(password, password);
    expect(cubit.state, at(SimpleLoginStep.phrase));
    expect(cubit.state.phrase, fakePhrase);
    cubit.phraseWrittenDown();
    expect(cubit.state, at(SimpleLoginStep.phraseCheck));
    await cubit.phraseChecked(wordsAsked(cubit.state));
  }

  group('someone new', () {
    test('creates an account: the suggested handle checked, the password '
        'twice, the phrase shown and three words typed back, signed in '
        'only at the end', () async {
      final cubit = cubitFor();
      expect(cubit.state, at(SimpleLoginStep.browser));

      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.newcomer));
      expect(cubit.state.handle, 'anna_mueller');

      cubit.createChosen();
      expect(cubit.state, at(SimpleLoginStep.handle));
      expect(cubit.state.handleFree, isTrue);

      await cubit.handleEntered(' @anna_mueller ');
      expect(cubit.state, at(SimpleLoginStep.password));
      expect(cubit.state.handle, 'anna_mueller');
      expect(
        gateway.calls,
        isNot(contains('checkHandle')),
        reason: 'the instance suggests no handle anybody has',
      );

      await cubit.passwordEntered(password, 'correct horse batery');
      expect(cubit.state.passwordsDiffer, isTrue);
      await cubit.passwordEntered('too short', 'too short');
      expect(
        cubit.state,
        at(
          SimpleLoginStep.password,
          problem: const PasswordFailed(PasswordProblem.passwordTooShort),
        ),
      );

      await cubit.passwordEntered(password, password);
      cubit.phraseWrittenDown();
      await cubit.phraseChecked(['wrong', 'words', 'typed']);
      expect(cubit.state.phraseWrong, isTrue);
      cubit.phraseShownAgain();
      expect(cubit.state, at(SimpleLoginStep.phrase));
      expect(gateway.calls, isNot(contains('signUp')));
      expect(auth.status, const SignedOut());

      cubit.phraseWrittenDown();
      await cubit.phraseChecked(wordsAsked(cubit.state));

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(
        auth.status,
        const SignedIn(authUserId: 'person-1', isIdentified: true),
      );
      expect(gateway.accounts['person-1']!.handle, 'anna_mueller');
      expect(keys.kept.keys.toList(), ['person-1']);
    });

    test('learns on the handle that one typed is taken, and goes on with '
        'one free', () async {
      gateway.addAccount('person-9', subject: 'other', handle: 'anna');
      final cubit = cubitFor();
      await cubit.started();
      cubit.createChosen();

      await cubit.handleEntered('anna');
      expect(
        cubit.state,
        at(
          SimpleLoginStep.handle,
          problem: const SimpleLoginFailed(SimpleLoginProblem.handleTaken),
        ),
      );
      expect(cubit.state.handleFree, isFalse);

      await cubit.handleEntered('admin');
      expect(
        cubit.state.problem,
        const SimpleLoginFailed(SimpleLoginProblem.handleReserved),
      );

      await cubit.handleEntered('anna_m');
      expect(cubit.state, at(SimpleLoginStep.password));
      expect(cubit.state.handleFree, isTrue);
    });

    test('goes back to the handle when it was taken meanwhile, then on with '
        'the keys made, once changed', () async {
      final cubit = cubitFor();
      await cubit.started();
      cubit.createChosen();
      await cubit.handleEntered('anna_mueller');
      gateway.addAccount('person-9', subject: 'other', handle: 'anna_mueller');

      await makeKeys(cubit);
      expect(
        cubit.state,
        at(
          SimpleLoginStep.handle,
          problem: const SimpleLoginFailed(SimpleLoginProblem.handleTaken),
        ),
      );

      await cubit.handleEntered('anna_m');

      expect(cubit.state, at(SimpleLoginStep.done));
      final person = auth.usedSessions.single.authUserId;
      expect(gateway.accounts[person]!.handle, 'anna_m');
    });

    test('links the account they have again, by its handle and recovery '
        'phrase, refusing a phrase that does not fit', () async {
      final material = await crypto.newKeys(password);
      gateway.addAccount(
        'person-9',
        subject: 'simplelogin-lost',
        handle: 'anna',
        keys: material.setup,
      );
      final cubit = cubitFor();
      await cubit.started();

      cubit.linkChosen();
      expect(cubit.state, at(SimpleLoginStep.mend));
      await cubit.mendEntered('anna', otherFakePhrase);
      expect(
        cubit.state,
        at(
          SimpleLoginStep.mend,
          problem: const PasswordFailed(PasswordProblem.phraseDoesNotFit),
        ),
      );
      cubit.choiceShownAgain();
      expect(cubit.state, at(SimpleLoginStep.newcomer));
      cubit.linkChosen();

      await cubit.mendEntered('@anna', fakePhrase);

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(gateway.linked, {'simplelogin-anna': 'person-9'});
      expect(keys.kept, {'person-9': material.keys});
    });

    test('begins again once their sign-in ran out', () async {
      final cubit = cubitFor();
      await cubit.started();
      cubit.linkChosen();
      gateway.failing = const SimpleLoginFailed(SimpleLoginProblem.startAgain);

      await cubit.mendEntered('anna', fakePhrase);
      expect(
        cubit.state,
        at(
          SimpleLoginStep.browser,
          problem: const SimpleLoginFailed(SimpleLoginProblem.startAgain),
        ),
      );

      gateway.failing = null;
      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.newcomer));
    });
  });

  group('an account', () {
    test('opens its keys with the password, refusing a wrong one', () async {
      final material = await crypto.newKeys(password);
      gateway.addAccount(
        'person-9',
        subject: 'simplelogin-anna',
        handle: 'anna',
        keys: material.setup,
      );
      final cubit = cubitFor();
      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.unlock));
      expect(cubit.state.signedInAs, 'anna');

      await cubit.unlockEntered('wrong horse battery');
      expect(
        cubit.state,
        at(
          SimpleLoginStep.unlock,
          problem: const PasswordFailed(PasswordProblem.wrongCredentials),
        ),
      );
      expect(auth.status, const SignedOut());

      await cubit.unlockEntered(password);

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(
        auth.status,
        const SignedIn(authUserId: 'person-9', isIdentified: true),
      );
      expect(keys.kept, {'person-9': material.keys});
    });

    test('of before, without keys, makes them with the handle it '
        'lacks', () async {
      gateway.addAccount('person-9', subject: 'simplelogin-anna');
      final cubit = cubitFor();
      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.handle));

      await cubit.handleEntered('anna');
      expect(cubit.state, at(SimpleLoginStep.password));
      expect(gateway.calls, isNot(contains('checkHandle')));
      await makeKeys(cubit);

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(gateway.accounts['person-9']!.handle, 'anna');
      expect(gateway.accounts['person-9']!.keys, isNotNull);
      expect(auth.usedSessions.single.authUserId, 'person-9');
    });
  });

  group("SimpleLogin added to the account of the device's person", () {
    test('an anonymous person keeps their device keys, and is identified '
        'once the keys are set', () async {
      await auth.signInAnonymously();
      final deviceKeys = crypto.keysNumbered(1);
      keys.kept['anonymous-1'] = deviceKeys;
      final cubit = cubitFor(link: true);

      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.handle));
      await cubit.handleEntered('anna');
      await makeKeys(cubit);

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(
        auth.status,
        const SignedIn(authUserId: 'anonymous-1', isIdentified: true),
      );
      expect(keys.kept, {'anonymous-1': deviceKeys});
      expect(auth.usedSessions, isEmpty);
    });

    test('an account with keys is done at once', () async {
      final material = await crypto.newKeys(password);
      auth = FakeAuthGateway(
        status: const SignedIn(authUserId: 'person-9', isIdentified: true),
      );
      gateway = FakeSimpleLoginGateway(auth);
      gateway.accounts['person-9'] = FakeSimpleLoginAccount(
        handle: 'anna',
        keys: material.setup,
      );
      simpleLogin = SimpleLoginRepository(
        gateway,
        browser,
        crypto,
        keys,
        auth,
        callbackScheme: 'app.halkyon.test',
        loopbackPort: 43823,
        platform: TargetPlatform.android,
      );
      final cubit = cubitFor(link: true);

      await cubit.started();

      expect(cubit.state, at(SimpleLoginStep.done));
      expect(gateway.linked, {'simplelogin-anna': 'person-9'});
    });
  });

  group('the browser', () {
    test('closed, the sign-in ends with nothing done', () async {
      browser.comesBack = () => null;
      final cubit = cubitFor();

      await cubit.started();

      expect(cubit.state, at(SimpleLoginStep.closed));
    });

    test("refused on SimpleLogin's page, says so and can begin "
        'again', () async {
      browser.comesBack = () => const OidcDenied('access_denied');
      final cubit = cubitFor();

      await cubit.started();
      expect(
        cubit.state,
        at(
          SimpleLoginStep.browser,
          problem: const SimpleLoginFailed(SimpleLoginProblem.denied),
        ),
      );

      browser.comesBack = null;
      await cubit.started();
      expect(cubit.state, at(SimpleLoginStep.newcomer));
    });

    test('is no longer waited for once the sheet closes', () async {
      final waiting = Completer<OidcCallback?>();
      browser.comesBack = () => waiting.future;
      final cubit = SimpleLoginCubit(simpleLogin);

      unawaited(cubit.started());
      await Future<void>.delayed(Duration.zero);
      expect(cubit.state, at(SimpleLoginStep.browser, busy: true));
      await cubit.close();

      expect(browser.cancelled, 1);
      waiting.complete(null);
    });

    test('is no longer waited for once cancelled', () async {
      final cubit = cubitFor();

      await cubit.cancelled();

      expect(browser.cancelled, 1);
    });
  });
}