video-create/web/server/db/index.ts

import Database from 'better-sqlite3';
import path from 'path';
import fs from 'fs';
import { fileURLToPath } from 'url';
import { SCHEMA_SQL } from './schema';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const DB_PATH = path.resolve(__dirname, '..', '..', 'data', 'meitu-agent.db');

let db: Database.Database;

export function getDb(): Database.Database {
  if (!db) {
    const dir = path.dirname(DB_PATH);
    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
    db = new Database(DB_PATH);
    db.pragma('journal_mode = WAL');
    db.pragma('foreign_keys = ON');
  }
  return db;
}

// Ensure a column exists on a table, add it with DEFAULT if missing
function ensureColumn(d: Database.Database, table: string, column: string, definition: string) {
  const cols = d.prepare(`PRAGMA table_info('${table}')`).all() as { name: string }[];
  if (!cols.some((c) => c.name === column)) {
    d.exec(`ALTER TABLE ${table} ADD COLUMN ${column} ${definition}`);
  }
}

export function initDb(): void {
  const d = getDb();
  d.exec(SCHEMA_SQL);

  // Migrations for existing databases
  ensureColumn(d, 'conversations', 'pinned', 'INTEGER NOT NULL DEFAULT 0');
}