import Database from "better-sqlite3";
import { existsSync, statSync } from "node:fs";
import path from "node:path";

// Base canonique Toveli, ouverte en lecture seule. Le fichier est remplacé atomiquement chaque nuit
// par scripts/sync.ts : on rouvre le handle si l'inode a changé (sinon on lirait l'ancien fichier).
const DB_PATH = process.env.TOVELI_DB ?? path.join(process.cwd(), "data", "toveli.db");
let handle: Database.Database | null = null;
let inode = -1;

export function dbAvailable(): boolean { return existsSync(/*turbopackIgnore: true*/ DB_PATH); }

export function getDb(): Database.Database {
  if (!existsSync(/*turbopackIgnore: true*/ DB_PATH)) throw new Error(`Base Toveli absente : ${DB_PATH} — exécuter « pnpm sync »`);
  const ino = statSync(/*turbopackIgnore: true*/ DB_PATH).ino;
  if (!handle || ino !== inode) {
    handle?.close();
    handle = new Database(DB_PATH, { readonly: true, fileMustExist: true });
    handle.pragma("cache_size = -262144"); // 256 Mo
    handle.pragma("mmap_size = 2147483648");
    inode = ino;
  }
  return handle;
}

export function meta(key: string): string | null {
  try { const r = getDb().prepare("SELECT value FROM meta WHERE key = ?").get(key) as { value: string } | undefined; return r?.value ?? null; } catch { return null; }
}