coms3011a-lab1/lib/db.ts

import fs from "node:fs";
import path from "node:path";
import { DatabaseSync } from "node:sqlite";

type DatabaseGlobal = typeof globalThis & {
  plannerDatabase?: DatabaseSync;
  plannerDatabasePath?: string;
};

const schemaPath = path.join(process.cwd(), "db", "schema.sql");
const defaultDatabasePath = path.join(process.cwd(), "data", "planner.sqlite");

export function getDatabase() {
  const databasePath = process.env.TASKS_DB_PATH ?? defaultDatabasePath;
  const globalDatabase = globalThis as DatabaseGlobal;

  if (
    globalDatabase.plannerDatabase &&
    globalDatabase.plannerDatabasePath === databasePath
  ) {
    return globalDatabase.plannerDatabase;
  }

  fs.mkdirSync(path.dirname(databasePath), { recursive: true });

  const database = new DatabaseSync(databasePath);
  const schema = fs.readFileSync(schemaPath, "utf8");

  database.exec("PRAGMA foreign_keys = ON;");
  database.exec(schema);

  globalDatabase.plannerDatabase = database;
  globalDatabase.plannerDatabasePath = databasePath;

  return database;
}