add getter for courseLookup...

allows for initDataLayer to injest env values first

Author: NiloCK

packages/db/src/impl/pouch/courseLookupDB.ts

@@ -1,5 +1,5 @@
 import pouch from './pouchdb-setup';
-// import { ENV } from '@/factory';
+import { ENV } from '@/factory';
 
 const courseLookupDBTitle = 'coursedb-lookup';
 
@@ -13,23 +13,76 @@ interface CourseLookupDoc {
 console.log(`COURSELOOKUP FILE RUNNING`);
 
 /**
- * a k-v indexes created courses.
- *
- * k: courseID
- * v: course name
+ * A Lookup table of existant courses. Each docID in this DB correspondes to a
+ * course database whose name is `coursedb-{docID}`
  */
 export default class CourseLookup {
-  // [ ] this db should be read only for public, admin-write only
-  // static _db: PouchDB.Database = new pouch(
-  //   ENV.COUCHDB_SERVER_PROTOCOL + '://' + ENV.COUCHDB_SERVER_URL + courseLookupDBTitle,
-  //   {
-  //     // skip_setup: true,
-  //   }
-  // );
-
-  static _db: PouchDB.Database = new pouch('http://localhost:5984/' + courseLookupDBTitle, {
-    skip_setup: true,
-  });
+  // [ ] this db should be read only for public, admin-only for write
+  // Cache for the PouchDB instance
+  private static _dbInstance: PouchDB.Database | null = null;
+
+  /**
+   * Static getter for the PouchDB database instance.
+   * Connects using ENV variables and caches the instance.
+   * Throws an error if required ENV variables are not set.
+   */
+  private static get _db(): PouchDB.Database {
+    // Return cached instance if available
+    if (this._dbInstance) {
+      return this._dbInstance;
+    }
+
+    // --- Check required environment variables ---
+    if (ENV.COUCHDB_SERVER_URL === 'NOT_SET' || !ENV.COUCHDB_SERVER_URL) {
+      throw new Error(
+        'CourseLookup.db: COUCHDB_SERVER_URL is not set. Ensure initializeDataLayer has been called with valid configuration.'
+      );
+    }
+    if (ENV.COUCHDB_SERVER_PROTOCOL === 'NOT_SET' || !ENV.COUCHDB_SERVER_PROTOCOL) {
+      throw new Error(
+        'CourseLookup.db: COUCHDB_SERVER_PROTOCOL is not set. Ensure initializeDataLayer has been called with valid configuration.'
+      );
+    }
+
+    // --- Construct connection options ---
+    const dbUrl = `${ENV.COUCHDB_SERVER_PROTOCOL}://${ENV.COUCHDB_SERVER_URL}/${courseLookupDBTitle}`;
+    const options: PouchDB.Configuration.RemoteDatabaseConfiguration = {
+      skip_setup: true, // Keep the original option
+      // fetch: (url, opts) => { // Optional: Add for debugging network requests
+      //   console.log('PouchDB fetch:', url, opts);
+      //   return pouch.fetch(url, opts);
+      // }
+    };
+
+    // Add authentication if both username and password are provided
+    if (ENV.COUCHDB_USERNAME && ENV.COUCHDB_PASSWORD) {
+      options.auth = {
+        username: ENV.COUCHDB_USERNAME,
+        password: ENV.COUCHDB_PASSWORD,
+      };
+      console.log(`CourseLookup: Connecting to ${dbUrl} with authentication.`);
+    } else {
+      console.log(`CourseLookup: Connecting to ${dbUrl} without authentication.`);
+    }
+
+    // --- Create and cache the PouchDB instance ---
+    try {
+      this._dbInstance = new pouch(dbUrl, options);
+      console.log(`CourseLookup: Database instance created for ${courseLookupDBTitle}.`);
+      return this._dbInstance;
+    } catch (error) {
+      console.error(`CourseLookup: Failed to create PouchDB instance for ${dbUrl}`, error);
+      // Reset cache attempt on failure
+      this._dbInstance = null;
+      // Re-throw the error to indicate connection failure
+      throw new Error(
+        `CourseLookup: Failed to initialize database connection: ${
+          error instanceof Error ? error.message : String(error)
+        }`
+      );
+    }
+  }
+
   /**
    * Adds a new course to the lookup database, and returns the courseID
    * @param courseName