import 'package:block2_spike/block2_spike.dart';
import 'package:test/test.dart';

/// Pure web-of-trust rules (Duniter: N certs from members + within distance D).
/// This is the `commons_core`-worthy piece: deterministic, no I/O.
void main() {
  final now = DateTime(2026, 7, 10);
  Certification cert(String a, String b, {DateTime? expires, bool revoked = false}) =>
      Certification(
        issuer: a,
        subject: b,
        issuedAt: DateTime(2026),
        expiresAt: expires,
        revoked: revoked,
      );

  test('seeds are always members', () {
    final wot = WebOfTrust.fromCertifications([], now: now);
    expect(
      wot.members(seeds: {'s1'}, threshold: 5, maxDistance: 5),
      contains('s1'),
    );
  });

  test('reaches the threshold from member certifiers → becomes known', () {
    final seeds = {'s1', 's2', 's3', 's4', 's5'};
    final certs = [for (final s in seeds) cert(s, 'newcomer')];
    final wot = WebOfTrust.fromCertifications(certs, now: now);
    final members = wot.members(seeds: seeds, threshold: 5, maxDistance: 5);
    expect(members, contains('newcomer'));
  });

  test('below the threshold stays unknown', () {
    final seeds = {'s1', 's2', 's3', 's4', 's5'};
    final certs = [cert('s1', 'x'), cert('s2', 'x')]; // only 2 of 5
    final wot = WebOfTrust.fromCertifications(certs, now: now);
    expect(
      wot.members(seeds: seeds, threshold: 5, maxDistance: 5),
      isNot(contains('x')),
    );
  });

  test('membership is transitive via a fixpoint (needs a to count for b)', () {
    final seeds = {'s1', 's2'};
    final certs = [
      cert('s1', 'a'), cert('s2', 'a'), // a: 2 member certs → member
      cert('a', 'b'), cert('s2', 'b'), // b: certified by a (now member) + s2
    ];
    final wot = WebOfTrust.fromCertifications(certs, now: now);
    final members = wot.members(seeds: seeds, threshold: 2, maxDistance: 5);
    expect(members, containsAll(['a', 'b']));
  });

  test('distance rule cuts off far-away nodes even if well-certified', () {
    // s → a → b → c → d → e chain; only s is a seed; threshold 1.
    final seeds = {'s'};
    final certs = [
      cert('s', 'a'),
      cert('a', 'b'),
      cert('b', 'c'),
      cert('c', 'd'),
      cert('d', 'e'),
    ];
    final wot = WebOfTrust.fromCertifications(certs, now: now);
    final members = wot.members(seeds: seeds, threshold: 1, maxDistance: 2);
    expect(members, containsAll(['a', 'b'])); // dist 1 and 2
    expect(members, isNot(contains('c'))); // dist 3 > maxDistance
    expect(members, isNot(contains('e')));
  });

  test('expired and revoked certifications do not count', () {
    final seeds = {'s1', 's2', 's3', 's4', 's5'};
    final certs = [
      cert('s1', 'x'),
      cert('s2', 'x'),
      cert('s3', 'x'),
      cert('s4', 'x', expires: DateTime(2020)), // expired
      cert('s5', 'x', revoked: true), // revoked
    ];
    final wot = WebOfTrust.fromCertifications(certs, now: now);
    expect(wot.certifierCount('x'), 3, reason: 'expired+revoked dropped');
    expect(
      wot.members(seeds: seeds, threshold: 5, maxDistance: 5),
      isNot(contains('x')),
    );
  });

  test('self-certification is ignored', () {
    final wot = WebOfTrust.fromCertifications([cert('a', 'a')], now: now);
    expect(wot.certifierCount('a'), 0);
  });
}