import Database from 'better-sqlite3';
import fs from 'node:fs';
import path from 'node:path';
import { env } from '$env/dynamic/private';

let _db: Database.Database | null = null;

export function getDb(): Database.Database {
	if (_db) return _db;

	const DB_PATH = env.DB_PATH ?? path.join(process.cwd(), 'data', 'game-grid.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');
	initSchema(_db);
	return _db;
}

function initSchema(db: Database.Database): void {
	db.exec(`
    CREATE TABLE IF NOT EXISTS series (
      id              INTEGER PRIMARY KEY AUTOINCREMENT,
      slug            TEXT NOT NULL UNIQUE,
      title           TEXT NOT NULL,
      library         TEXT NOT NULL CHECK(library IN ('public','private')),
      folder_path     TEXT NOT NULL,
      has_cover       INTEGER NOT NULL DEFAULT 0,
      last_scanned_at TEXT NOT NULL DEFAULT (datetime('now')),
      created_at      TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS games (
      id              INTEGER PRIMARY KEY AUTOINCREMENT,
      slug            TEXT NOT NULL UNIQUE,
      title           TEXT NOT NULL,
      library         TEXT NOT NULL CHECK(library IN ('public','private')),
      folder_path     TEXT NOT NULL,
      description     TEXT NOT NULL DEFAULT '',
      genre           TEXT NOT NULL DEFAULT '',
      has_cover       INTEGER NOT NULL DEFAULT 0,
      has_wide        INTEGER NOT NULL DEFAULT 0,
      last_scanned_at TEXT NOT NULL DEFAULT (datetime('now')),
      created_at      TEXT NOT NULL DEFAULT (datetime('now'))
    );

    CREATE TABLE IF NOT EXISTS game_files (
      id        INTEGER PRIMARY KEY AUTOINCREMENT,
      game_id   INTEGER NOT NULL REFERENCES games(id) ON DELETE CASCADE,
      filename  TEXT NOT NULL,
      rel_path  TEXT NOT NULL,
      platform  TEXT NOT NULL,
      is_dir    INTEGER NOT NULL DEFAULT 0,
      file_size INTEGER NOT NULL DEFAULT 0
    );

    CREATE TABLE IF NOT EXISTS screenshots (
      id         INTEGER PRIMARY KEY AUTOINCREMENT,
      game_id    INTEGER NOT NULL REFERENCES games(id) ON DELETE CASCADE,
      filename   TEXT NOT NULL,
      rel_path   TEXT NOT NULL,
      sort_order INTEGER NOT NULL DEFAULT 0
    );

    CREATE TABLE IF NOT EXISTS tags (
      id   INTEGER PRIMARY KEY AUTOINCREMENT,
      name TEXT NOT NULL UNIQUE COLLATE NOCASE
    );

    CREATE TABLE IF NOT EXISTS game_tags (
      game_id INTEGER NOT NULL REFERENCES games(id) ON DELETE CASCADE,
      tag_id  INTEGER NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
      PRIMARY KEY (game_id, tag_id)
    );
  `);

	const cols = db.prepare('PRAGMA table_info(games)').all() as Array<{ name: string }>;
	if (!cols.some((c) => c.name === 'series_id')) {
		db.exec(
			'ALTER TABLE games ADD COLUMN series_id INTEGER REFERENCES series(id) ON DELETE SET NULL'
		);
	}
}