Registry API Refactoring (#144)

* Refactor core to use a flexible registry pattern

- Introduce a new registry mechanism for mailer providers
- Extract mailer provider enum to a separate file
- Implement dynamic mailer loading using a registry
- Update package dependencies and exports
- Improve modularity and extensibility of mailer implementation

* Refactor monitoring and billing services to use a flexible registry pattern

- Introduce a shared registry mechanism for dynamic service loading
- Replace static switch-based implementations with a registry-based approach
- Update instrumentation, CMS, and monitoring services to use the new registry
- Improve modularity and extensibility of service implementations
- Add Zod-based type-safe provider validation

* Simplify async registration in monitoring and billing services

- Remove unnecessary async wrappers for no-op registrations
- Update type definitions to support both async and sync registration functions
- Standardize registration approach for Paddle and Sentry providers

* Remove Tailwind package from packages where it is not being needed

* Remove Tailwind config references from pnpm-lock.yaml

* Update instrumentation registry to support dynamic monitoring providers

- Modify type definition to use NonNullable MonitoringProvider
- Import MonitoringProvider type from get-monitoring-provider
- Enhance type safety for instrumentation registration

packages/shared/src/registry/index.ts

@@ -0,0 +1,108 @@
+/**
+ * Implementation factory type
+ */
+export type ImplementationFactory<T> = () =>
+  | T
+  | Promise<T>;
+
+/**
+ * Public API types with improved get method
+ */
+export interface Registry<T, Names extends string> {
+  register: (
+    name: Names,
+    factory: ImplementationFactory<T>,
+  ) => Registry<T, Names>;
+
+  // Overloaded get method that infers return types based on input.
+  get: {
+    <K extends Names>(name: K): Promise<T>;
+    <K extends [Names, ...Names[]]>(
+      ...names: K
+    ): Promise<{ [P in keyof K]: T }>;
+  };
+
+  setup: (group?: string) => Promise<void>;
+  addSetup: (
+    group: string,
+    callback: () => Promise<void>,
+  ) => Registry<T, Names>;
+}
+
+/**
+ * @name createRegistry
+ * @description Creates a new registry instance with the provided implementations.
+ * @returns A new registry instance.
+ */
+export function createRegistry<
+  T,
+  Names extends string = string,
+>(): Registry<T, Names> {
+  const implementations = new Map<Names, ImplementationFactory<T>>();
+  const setupCallbacks = new Map<string, Array<() => Promise<void>>>();
+  const setupPromises = new Map<string, Promise<void>>();
+
+  const registry: Registry<T, Names> = {
+    register(name, factory) {
+      implementations.set(name, factory);
+      return registry;
+    },
+
+    // Updated get method overload that supports tuple inference
+    get: (async (...names: Names[]) => {
+      await registry.setup();
+
+      if (names.length === 1) {
+        return await getImplementation(names[0]!);
+      }
+
+      return await Promise.all(names.map((name) => getImplementation(name)));
+    }) as Registry<T, Names>['get'],
+
+    async setup(group?: string) {
+      if (group) {
+        if (!setupPromises.has(group)) {
+          const callbacks = setupCallbacks.get(group) ?? [];
+
+          setupPromises.set(
+            group,
+            Promise.all(callbacks.map((cb) => cb())).then(() => void 0),
+          );
+        }
+
+        return setupPromises.get(group);
+      }
+
+      const groups = Array.from(setupCallbacks.keys());
+
+      await Promise.all(groups.map((group) => registry.setup(group)));
+    },
+
+    addSetup(group, callback) {
+      if (!setupCallbacks.has(group)) {
+        setupCallbacks.set(group, []);
+      }
+
+      setupCallbacks.get(group)!.push(callback);
+      return registry;
+    },
+  };
+
+  async function getImplementation(name: Names) {
+    const factory = implementations.get(name);
+
+    if (!factory) {
+      throw new Error(`Implementation "${name}" not found`);
+    }
+
+    const implementation = await factory();
+
+    if (!implementation) {
+      throw new Error(`Implementation "${name}" is not available`);
+    }
+
+    return implementation;
+  }
+
+  return registry;
+}