import Database from 'better-sqlite3'
import { mkdirSync } from 'fs'
import { dirname } from 'path'

let _db: InstanceType<typeof Database> | null = null

export function useDb() {
  if (_db) return _db

  const dbPath = process.env.DB_PATH || './data/brainstorm.db'

  mkdirSync(dirname(dbPath), { recursive: true })

  _db = new Database(dbPath)
  _db.pragma('journal_mode = WAL')
  _db.pragma('foreign_keys = ON')

  _db.exec(`
    CREATE TABLE IF NOT EXISTS ideas (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      text TEXT NOT NULL,
      category TEXT NOT NULL DEFAULT 'General',
      votes INTEGER NOT NULL DEFAULT 0,
      hidden INTEGER NOT NULL DEFAULT 0,
      created_at TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS vote_log (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      idea_id INTEGER NOT NULL REFERENCES ideas(id) ON DELETE CASCADE,
      voter_hash TEXT NOT NULL,
      created_at TEXT NOT NULL DEFAULT (datetime('now')),
      UNIQUE(idea_id, voter_hash)
    );

    CREATE TABLE IF NOT EXISTS sessions (
      token TEXT PRIMARY KEY,
      created_at TEXT NOT NULL DEFAULT (datetime('now')),
      expires_at TEXT NOT NULL
    );
  `)

  return _db
}