import { STORAGE_KEY } from '../config.js';

function readAll() {
  try {
    const raw = localStorage.getItem(STORAGE_KEY);
    return raw ? JSON.parse(raw) : {};
  } catch (e) {
    return {};
  }
}

function writeAll(all) {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(all));
  } catch (e) {
    // localStorage unavailable (e.g. private browsing) - progress just won't persist
  }
}

export function isLevelComplete(levelId) {
  return Boolean(readAll()[levelId]);
}

// Records a completed run. kidsSaved/kidsTotal are kept (they're how
// "isLevelComplete" and any legacy saves work), and bestScore is the
// player's highest final score - the level select map shows it under each
// cleared node. A run only "counts" if it improves the best on either
// axis, but whichever axis improved wins; both are kept at their max.
export function markLevelComplete(levelId, kidsSaved, kidsTotal, score = null) {
  const all = readAll();
  const existing = all[levelId] || {};
  all[levelId] = {
    kidsSaved: Math.max(existing.kidsSaved || 0, kidsSaved),
    kidsTotal,
    bestScore: Math.max(existing.bestScore || 0, score || 0),
  };
  writeAll(all);
}

export function getLevelResult(levelId) {
  return readAll()[levelId] || null;
}

// The player's best score for a level, or null if none has been recorded
// yet (e.g. a legacy save from before best scores existed).
export function getBestScore(levelId) {
  const result = readAll()[levelId];
  return result && typeof result.bestScore === 'number' && result.bestScore > 0 ? result.bestScore : null;
}