export type ExerciseType =
  | 'multiple-choice'
  | 'translation'
  | 'matching-pairs'
  | 'fill-in-the-blank'
  | 'speak';

export interface BaseExercise {
  type: ExerciseType;
  prompt: string;
  promptAudio?: boolean;
  audioText?: string;
}

export interface MultipleChoiceExercise extends BaseExercise {
  type: 'multiple-choice';
  choices: string[];
  correctIndex: number;
}

export interface TranslationExercise extends BaseExercise {
  type: 'translation';
  acceptedAnswers: string[];
  hint?: string;
}

export interface MatchingPairsExercise extends BaseExercise {
  type: 'matching-pairs';
  pairs: { left: string; right: string }[];
}

export interface FillInTheBlankExercise extends BaseExercise {
  type: 'fill-in-the-blank';
  sentence: string;
  blank: string;
  hint?: string;
  wordBank?: string[];
}

export interface SpeakExercise extends BaseExercise {
  type: 'speak';
  phrase: string;
  acceptedAnswers: string[];
}

export type Exercise =
  | MultipleChoiceExercise
  | TranslationExercise
  | MatchingPairsExercise
  | FillInTheBlankExercise
  | SpeakExercise;

export interface Lesson {
  id: string;
  topicId: string;
  title: string;
  xpReward: number;
  exercises: Exercise[];
}

export interface Topic {
  id: string;
  name: string;
  icon: string;
  description: string;
  section: number;
  prerequisites: string[];
  lessons: string[];
}

export interface Section {
  id: number;
  name: string;
  description: string;
}

export interface TopicsConfig {
  sections: Section[];
  topics: Topic[];
}