# Summary of Self-Awareness Layer Implementation

## Goal

The primary goal of this task was to implement a runtime Self-Awareness layer within the Next.js + Vitest project. This layer is designed to provide insights into the application's runtime behavior by publishing structured events, maintaining a system snapshot, and exposing APIs for observability, all while being safely guarded by feature flags.

## Implementation Details

A new "Self-Awareness" module was created under `lib/awareness`. This module consists of the following components:

1.  **Event System (`lib/awareness/events.ts`):**
    *   Defined structured event types: `DESKTOP_LOADED`, `WINDOW_OPENED`, `WINDOW_FOCUSED`, `WINDOW_CLOSED`, and `TELEMETRY_METRIC`.
    *   Established runtime guards (`AWARENESS_ENABLED`, `TELEMETRY_ENABLED`) based on `NODE_ENV` and environment variables to ensure the feature is disabled in production unless explicitly enabled.

2.  **In-Memory Snapshot (`lib/awareness/snapshot.ts`):**
    *   Maintains a minimal in-memory snapshot of the system state, including open window IDs, the active window ID, and window counts.
    *   The snapshot is updated automatically whenever a relevant event is published.
    *   Exposes a `getSnapshot()` function to retrieve the current state.

3.  **Event Bus (`lib/awareness/bus.ts`):**
    *   A simple publish/subscribe event bus.
    *   The `publish` function is the central point for dispatching events. It updates the snapshot and notifies any subscribers.
    *   The `subscribe` function allows other parts of the application to listen for and react to awareness events.

4.  **Integration into Application:**
    *   **`app/page.tsx`**: Integrated event publishing for `WINDOW_OPENED`, `WINDOW_CLOSED`, `DESKTOP_LOADED` (after login), and a `TELEMETRY_METRIC` for desktop render time.
    *   **`components/Desktop.tsx`**: Integrated event publishing for `DESKTOP_LOADED` (on initial mount) and `WINDOW_FOCUSED`.

## New Files Created

*   `lib/awareness/events.ts`: Defines event types, payloads, and runtime guards.
*   `lib/awareness/bus.ts`: Implements the event bus (publish/subscribe).
*   `lib/awareness/snapshot.ts`: Manages the in-memory system snapshot.
*   `lib/awareness/index.ts`: A barrel file for easy importing of awareness modules.
*   `tests/awareness/awareness.spec.ts`: Contains unit tests for the new awareness layer.

## Modified Files

*   `vitest.config.ts`: Updated to include the new `lib/` directory in test coverage analysis.
*   `app/page.tsx`: Modified to publish window and telemetry events.
*   `components/Desktop.tsx`: Modified to publish desktop and window focus events.

## Verification

*   A dedicated test suite (`tests/awareness/awareness.spec.ts`) was created to validate the functionality of the awareness layer. These tests ensure that:
    *   Events are published and subscribed to correctly.
    *   The system snapshot is accurately updated in response to events.
    *   The state is properly reset between tests.
*   The existing test suites were also run to ensure that the new functionality did not introduce any regressions. All tests passed successfully.
