import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
import 'package:halkyon_learn_flutter/src/feature/publish/data/publish_gateway.dart';
import 'package:halkyon_learn_flutter/src/feature/publish/model/publication.dart';

/// A [PublishGateway] in memory, on an instance whose account domain is
/// `halkyon.eu`, for the person `raisondetredev`: each publish a release
/// (unless [refusals] has one waiting), the name fixed from the first.
class FakePublishGateway({
  /// The studysets published, by id.
  final Map<String, Publication> publications = const {},
}) implements PublishGateway {
  late final _publications = {...publications};

  /// Refusals to answer the next publishes with, the first first.
  final refusals = <PublishRefused>[];

  /// What each publish was asked: the studyset, name and notes.
  final publishes = <({String studysetId, String slug, String notes})>[];

  /// The description for Explore each publish sent, in order.
  final descriptions = <RichContent?>[];

  /// When set, every request fails with it.
  Exception? fail;

  @override
  Future<Publication?> publication(String studysetId) async {
    if (fail case final error?) {
      throw error;
    }
    return _publications[studysetId];
  }

  @override
  Future<Set<String>> published() async {
    if (fail case final error?) {
      throw error;
    }
    return {
      for (final MapEntry(:key, :value) in _publications.entries)
        if (!value.withdrawn) key,
    };
  }

  @override
  Future<Publication> withdraw(String studysetId) async {
    if (fail case final error?) {
      throw error;
    }
    final before = _publications[studysetId]!;
    return _publications[studysetId] = Publication(
      publicId: before.publicId,
      slug: before.slug,
      location: before.location,
      releases: before.releases,
      withdrawn: true,
    );
  }

  @override
  Future<Publication> publish(
    String studysetId, {
    required String slug,
    required String notes,
    RichContent? description,
  }) async {
    if (fail case final error?) {
      throw error;
    }
    publishes.add((studysetId: studysetId, slug: slug, notes: notes));
    descriptions.add(description);
    if (refusals.isNotEmpty) {
      throw refusals.removeAt(0);
    }
    final before = _publications[studysetId];
    if (before != null && before.slug != slug) {
      throw PublishRefused(PublishProblem.slugFixed);
    }
    return _publications[studysetId] = Publication(
      publicId: before?.publicId ?? 'public-$studysetId',
      // A release brings a withdrawn studyset back.
      slug: slug,
      location: 'halkyon.eu/@raisondetredev/$slug',
      releases: [
        Release(
          version: (before?.latest?.version ?? 0) + 1,
          releasedAt: DateTime.utc(2026, 10, 9),
          license: 'CC-BY-SA-4.0',
          notes: notes,
          description: description,
        ),
        ...?before?.releases,
      ],
    );
  }
}