import { mkdirSync, existsSync } from 'node:fs'
import { join, resolve } from 'node:path'
import Database from 'better-sqlite3'
import { drizzle, type BetterSQLite3Database } from 'drizzle-orm/better-sqlite3'
import { migrate } from 'drizzle-orm/better-sqlite3/migrator'
import * as schema from '../db/schema'

export { schema }
export const tables = schema

let _db: BetterSQLite3Database<typeof schema> | null = null

export function dataDir() {
  // 运行时读取环境变量（runtimeConfig 的默认值在构建时就已固定）
  const dir = resolve(process.env.NOVEL_DATA_DIR || useRuntimeConfig().dataDir || './data')
  if (!existsSync(dir)) mkdirSync(dir, { recursive: true })
  return dir
}

function migrationsFolder() {
  const candidates = [
    resolve(process.cwd(), 'server/db/migrations'),
    resolve(process.cwd(), '../server/db/migrations')
  ]
  const found = candidates.find(p => existsSync(join(p, 'meta', '_journal.json')))
  if (!found) throw new Error('找不到数据库迁移目录 server/db/migrations，请在项目根目录启动应用')
  return found
}

export function useDb() {
  if (_db) return _db
  const sqlite = new Database(join(dataDir(), 'app.db'))
  sqlite.pragma('journal_mode = WAL')
  sqlite.pragma('foreign_keys = ON')
  _db = drizzle({ client: sqlite, schema })
  migrate(_db, { migrationsFolder: migrationsFolder() })
  return _db
}