/// Question pushed from the API over the SignalR questions hub.
class IncomingQuestion {
  const IncomingQuestion({
    required this.id,
    required this.text,
    required this.sentAt,
    this.unansweredCount = 1,
    this.sourceId = defaultSourceId,
    this.presentation = defaultPresentation,
    this.spokenWord,
    this.audioTitle,
    this.needsPrepare = false,
  });

  static const String defaultSourceId = 'market_history';
  static const String defaultPresentation = 'market_glyph_slider';

  final String id;
  final String text;
  final DateTime sentAt;

  /// Unanswered questions in the database for this user (from API).
  final int unansweredCount;

  /// Question source (`market_history`, `spelling`, …).
  final String sourceId;

  /// UI presentation key (`market_glyph_slider`, `spelling_word`, …).
  final String presentation;

  /// Word read aloud after server-side selection at tile load.
  final String? spokenWord;

  /// Question id referenced as the audio utterance title.
  final String? audioTitle;

  /// True when the server still needs tile-load word selection.
  final bool needsPrepare;

  /// Spelling pipeline source (word quiz and follow-up prompts).
  bool get isSpelling => sourceId == 'spelling';

  /// Typed spelling tile (hear word, type answer).
  bool get usesSpellingWordTile {
    if (presentation == 'spelling_word' || needsPrepare) {
      return true;
    }
    if (!isSpelling) {
      return false;
    }
    if (spokenWord != null && spokenWord!.isNotEmpty) {
      return true;
    }
    return !isSpellingFollowUp;
  }

  /// Spelling branch prompt to continue (+1) or pause (-1); uses swipe UI.
  bool get isSpellingFollowUp {
    if (!isSpelling || presentation == 'spelling_word') {
      return false;
    }
    final String lower = text.toLowerCase();
    return lower.contains('enter +1') ||
        lower.contains('another word') ||
        lower.contains('to pause');
  }

  bool get isMarketHistory => sourceId == 'market_history';

  factory IncomingQuestion.fromJson(Map<String, dynamic> json) {
    return IncomingQuestion(
      id: json['id'] as String,
      text: json['text'] as String,
      sentAt: DateTime.parse(json['sentAt'] as String).toUtc(),
      unansweredCount: (json['unansweredCount'] as num?)?.toInt() ?? 1,
      sourceId: json['sourceId'] as String? ?? defaultSourceId,
      presentation: json['presentation'] as String? ?? defaultPresentation,
      spokenWord: json['spokenWord'] as String?,
      audioTitle: json['audioTitle'] as String?,
      needsPrepare: json['needsPrepare'] as bool? ?? false,
    );
  }

  IncomingQuestion copyWith({
    String? text,
    String? spokenWord,
    String? audioTitle,
    int? unansweredCount,
    bool? needsPrepare,
  }) {
    return IncomingQuestion(
      id: id,
      text: text ?? this.text,
      sentAt: sentAt,
      unansweredCount: unansweredCount ?? this.unansweredCount,
      sourceId: sourceId,
      presentation: presentation,
      spokenWord: spokenWord ?? this.spokenWord,
      audioTitle: audioTitle ?? this.audioTitle,
      needsPrepare: needsPrepare ?? this.needsPrepare,
    );
  }
}