/**
 * PCQ-24 Reverse Scoring Configuration
 *
 * Reverse scoring formula: 7 - rawValue
 * After reversal, a value of 1 becomes 6, 2 becomes 5, 3 becomes 4, etc.
 *
 * Reverse-scored questions (as specified):
 *   - pcq_13  (Question 13 — Resilience dimension)
 *   - pcq_20  (Question 20 — Optimism dimension)
 *   - pcq_23  (Question 23 — Optimism dimension)
 *
 * Scale: 1–6
 * Reversed: 1→6, 2→5, 3→4, 4→3, 5→2, 6→1
 */

import type { PcqLikertValue } from '@/config/pcq24';

/** Set of question IDs that must be reverse-scored */
export const REVERSE_SCORED_QUESTIONS = new Set<string>(['pcq_13', 'pcq_20', 'pcq_23']);

/** Returns true if the given question ID is reverse-scored */
export function isReverseScored(questionId: string): boolean {
  return REVERSE_SCORED_QUESTIONS.has(questionId);
}

/**
 * Apply the PCQ-24 reverse scoring formula: 7 − rawValue
 *
 * @param rawValue - Likert value as string or number (expected 1–6)
 * @returns reversed score (6→1, 5→2, 4→3, 3→4, 2→5, 1→6)
 */
export function applyReverseScoring(rawValue: PcqLikertValue | string): number {
  return 7 - Number(rawValue);
}