import 'dart:convert';
import 'dart:typed_data';

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

/// Q2 — the `OfferTransport` seam must not leak inventory or an exact location.
/// The offer carries only a chosen summary; the wire event is checked byte-wise.
void main() {
  final key = NostrKey.deriveFromSeed(
    Uint8List.fromList(List.generate(32, (i) => i)),
  );
  final codec = Nip99Codec();

  // A realistic private-ish context: the caller ACCIDENTALLY passes a very
  // precise geohash and there is secret inventory the offer must never expose.
  const secretInventoryMarker = 'SECRET-LOT-12-KG-IN-SHED';
  const preciseGeohash = 'u09tunqmabc'; // ~sub-metre precision

  Offer sampleOffer() => Offer(
    id: 'offer-1',
    authorPubkeyHex: key.publicKeyHex,
    summary: 'Tomate rosa de Barbastro',
    type: OfferType.gift,
    category: 'Solanaceae',
    approxGeohash: preciseGeohash,
  );

  test('exact location is coarsened on the wire (never full precision)', () {
    final event = codec.encode(sampleOffer(), createdAt: 1000);
    final gTags = event.tags.where((t) => t[0] == 'g').map((t) => t[1]);
    // No geohash tag exceeds the coarse cap...
    expect(gTags.every((g) => g.length <= Nip99Codec.maxGeohashChars), isTrue);
    // ...and the precise fix never appears anywhere in the serialised event.
    final wire = jsonEncode(event.toJson());
    expect(wire, isNot(contains(preciseGeohash)));
    expect(wire, contains('u09t')); // coarse prefix is present
  });

  test('no inventory / address field can ride along (seam has none)', () {
    final event = codec.encode(sampleOffer(), createdAt: 1000);
    final wire = jsonEncode(event.toJson());
    expect(wire, isNot(contains(secretInventoryMarker)));
    // The event has no "location", "address" or "geo-exact" tag by construction.
    final tagNames = event.tags.map((t) => t[0]).toSet();
    expect(tagNames, isNot(contains('location')));
    expect(tagNames, isNot(contains('address')));
  });

  test('geohash ladder lets an area query match by exact tag', () {
    final event = codec.encode(sampleOffer(), createdAt: 1000);
    final gTags = event.tags.where((t) => t[0] == 'g').map((t) => t[1]).toList();
    expect(gTags, containsAll(['u', 'u0', 'u09', 'u09t']));
  });

  test('round-trips Offer ↔ NIP-99 event, only chosen fields survive', () {
    final original = Offer(
      id: 'offer-2',
      authorPubkeyHex: key.publicKeyHex,
      summary: 'Judía del ganxet',
      type: OfferType.sale,
      priceAmount: 3,
      priceCurrency: 'G1',
      category: 'Fabaceae',
      approxGeohash: 'sp3e9',
    );
    final event = codec.encode(original, createdAt: 1000)
      ..signWith(key.privateKeyHex);
    expect(event.verify(), isTrue);

    final decoded = codec.decode(event);
    expect(decoded.id, original.id);
    expect(decoded.summary, original.summary);
    expect(decoded.type, OfferType.sale);
    expect(decoded.priceAmount, 3);
    expect(decoded.priceCurrency, 'G1');
    expect(decoded.category, 'Fabaceae');
    expect(decoded.approxGeohash, 'sp3e9');
  });
}