import Database from 'better-sqlite3';
import path from 'path';
import fs from 'fs';

const DATA_DIR = process.env.DATA_DIR ?? path.join(process.cwd(), '.data');
const UPLOADS_DIR = path.join(DATA_DIR, 'uploads');
const DB_PATH = path.join(DATA_DIR, 'tally.db');

// Ensure directories exist
fs.mkdirSync(UPLOADS_DIR, { recursive: true });

const db = new Database(DB_PATH, { timeout: 5000 });

// Performance: WAL mode for concurrent reads + writes
db.pragma('journal_mode = WAL');
db.pragma('foreign_keys = ON');

// Schema migrations
db.exec(`
  CREATE TABLE IF NOT EXISTS groups (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT    NOT NULL,
    order_index INTEGER NOT NULL DEFAULT 0
  );

  CREATE TABLE IF NOT EXISTS counters (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT    NOT NULL,
    value       INTEGER NOT NULL DEFAULT 0,
    image_path  TEXT,
    group_id    INTEGER REFERENCES groups(id) ON DELETE SET NULL,
    order_index INTEGER NOT NULL DEFAULT 0
  );

  CREATE TABLE IF NOT EXISTS events (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    counter_id  INTEGER NOT NULL REFERENCES counters(id) ON DELETE CASCADE,
    delta       INTEGER NOT NULL,
    created_at  INTEGER NOT NULL
  );
  CREATE INDEX IF NOT EXISTS idx_events_counter ON events(counter_id);
  CREATE INDEX IF NOT EXISTS idx_events_date    ON events(created_at);
`);

export { UPLOADS_DIR };
export default db;