// Gemeinsame Ranglisten-Logik fuer Server (index.js) und CLI (admin.js).
// Zwei Ansichten aus derselben Datei: Allzeit-Top-5 + Heute-Top-10.

import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const DATA_DIR = join(__dirname, '..', 'data');
export const LEADERBOARD_FILE = join(DATA_DIR, 'leaderboard.json');

const ALLTIME_COUNT = 5;
const TODAY_COUNT = 10;
const KEEP_ALLTIME = 100; // Datei klein halten

export function readLeaderboard() {
  try {
    if (!existsSync(LEADERBOARD_FILE)) return [];
    const data = JSON.parse(readFileSync(LEADERBOARD_FILE, 'utf8'));
    return Array.isArray(data) ? data : [];
  } catch (err) {
    console.warn('[leaderboard] Datei unlesbar:', err.message);
    return [];
  }
}

export function writeLeaderboard(list) {
  if (!existsSync(DATA_DIR)) mkdirSync(DATA_DIR, { recursive: true });
  writeFileSync(LEADERBOARD_FILE, JSON.stringify(list, null, 2));
}

export function topN(list, n) {
  return [...list].sort((a, b) => b.score - a.score).slice(0, n);
}

// Server-lokaler Tages-Schluessel (YYYY-M-D)
function dayKey(d) {
  return `${d.getFullYear()}-${d.getMonth() + 1}-${d.getDate()}`;
}
export function isToday(entry) {
  return entry && entry.at && dayKey(new Date(entry.at)) === dayKey(new Date());
}

// Zwei Ranglisten aus derselben Liste
export function buildBoards(list) {
  return {
    allTime: topN(list, ALLTIME_COUNT),
    today: topN(list.filter(isToday), TODAY_COUNT),
  };
}

// Score eintragen -> aktualisierte Boards. Behaelt Allzeit-Top-100 + alle heutigen Eintraege.
export function addScore(name, score) {
  const list = readLeaderboard();
  list.push({ name, score, at: new Date().toISOString() });

  const keep = topN(list, KEEP_ALLTIME);
  const keepSet = new Set(keep);
  for (const e of list) if (isToday(e) && !keepSet.has(e)) keep.push(e);

  writeLeaderboard(keep);
  return buildBoards(keep);
}

// --- Verwaltung (CLI) ---

// Loescht alle Eintraege eines Spielers (Name case-insensitiv exakt). Gibt Anzahl zurueck.
export function deletePlayer(name) {
  const target = String(name || '').trim().toLowerCase();
  if (!target) return 0;
  const list = readLeaderboard();
  const kept = list.filter((e) => String(e.name || '').trim().toLowerCase() !== target);
  writeLeaderboard(kept);
  return list.length - kept.length;
}

// Leert die gesamte Rangliste. Gibt Anzahl geloeschter Eintraege zurueck.
export function clearAll() {
  const n = readLeaderboard().length;
  writeLeaderboard([]);
  return n;
}

// Entfernt nur die heutigen Eintraege. Gibt Anzahl zurueck.
export function clearToday() {
  const list = readLeaderboard();
  const kept = list.filter((e) => !isToday(e));
  writeLeaderboard(kept);
  return list.length - kept.length;
}