export type VocabularyRiskTestType = 'chinese-to-english' | 'audio-to-english' | 'multiple-choice';

export const DEFAULT_VOCABULARY_FULL_CORRECT_WORD_THRESHOLD = 50;
export const VOCABULARY_FULL_CORRECT_RISK_FLAG = 'large_batch_all_correct';

export const INVALIDATING_VOCABULARY_RISK_FLAGS: string[] = [
  'invalid_origin',
  'invalid_answer_proof',
  'invalid_question_token',
  'invalid_option_token',
  'invalid_submitted_at',
  'submitted_at_out_of_sync',
  'attempt_expired',
  'too_fast',
  'too_slow',
  'missing_choice_interaction',
  'missing_input_value_trace',
  'input_value_mismatch',
  'uniform_answer_intervals',
  'repeated_whole_second_intervals',
  VOCABULARY_FULL_CORRECT_RISK_FLAG
];

const parsePositiveThreshold = (value: unknown): number | undefined => {
  const parsed = Number(value);
  return Number.isFinite(parsed) && parsed > 0 ? parsed : undefined;
};

export const getVocabularyFullCorrectWordThreshold = (): number => {
  return parsePositiveThreshold(process.env.VOCABULARY_FULL_CORRECT_WORD_THRESHOLD) ??
    DEFAULT_VOCABULARY_FULL_CORRECT_WORD_THRESHOLD;
};

export const analyzeVocabularyAttemptResultRisk = ({
  testType,
  totalWords,
  correctWords,
  threshold = getVocabularyFullCorrectWordThreshold()
}: {
  testType: VocabularyRiskTestType | string;
  totalWords: number;
  correctWords: number;
  threshold?: number;
}): string[] => {
  const effectiveThreshold = parsePositiveThreshold(threshold) ??
    DEFAULT_VOCABULARY_FULL_CORRECT_WORD_THRESHOLD;
  const safeTotalWords = Number.isFinite(totalWords) ? totalWords : 0;
  const safeCorrectWords = Number.isFinite(correctWords) ? correctWords : 0;

  if (
    testType !== 'multiple-choice' &&
    safeTotalWords > effectiveThreshold &&
    safeTotalWords === safeCorrectWords
  ) {
    return [VOCABULARY_FULL_CORRECT_RISK_FLAG];
  }

  return [];
};