> ## Documentation Index
> Fetch the complete documentation index at: https://committ.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# February 19th, 2026

> SchedulerModule: Self-Chaining Native Alarm System

# February 19th, 2026

**The Native Scheduler is Alive: Self-Chaining Alarms**

Today we built the core native scheduling engine — a Kotlin module that reads task recurrence rules from the local SQLite database and creates self-perpetuating alarm chains entirely on the native side.

***

## SchedulerModule (New Expo Module)

**Commit:** `feat(native): add SchedulerModule with self-chaining alarm system`

Located at `modules/scheduler-module/`, this is the heart of our offline alarm system.

### How It Works

1. **Reads** task data from local SQLite (`commit.db`).
2. **Parses** recurrence rules (type, `days_of_week`, `time_windows`).
3. **Calculates** the next time slot using `findNextTimeSlot()`.
4. **Schedules** an action at the computed time via `Handler.postDelayed()`.
5. **Self-chains:** When the action fires, it automatically calculates and schedules the NEXT occurrence. The chain continues indefinitely.

### Architecture

* **Per-task chains** tracked via `ConcurrentHashMap<convexId, Runnable>`.
* **One-time tasks** end after first fire.
* **Recurring tasks** chain forever until cancelled.

### API

| Function                      | Purpose                                     |
| ----------------------------- | ------------------------------------------- |
| `scheduleForTask(convexId)`   | **CREATE**: Start a new chain for a task    |
| `rescheduleForTask(convexId)` | **UPDATE**: Cancel old chain, start new one |
| `cancelForTask(convexId)`     | **DELETE**: Stop the chain                  |
| `getActiveChains()`           | **DEBUG**: List all active chain IDs        |

### Frontend Integration

| Screen                       | When                  | Calls                 |
| ---------------------------- | --------------------- | --------------------- |
| `final.tsx` (Create)         | After local DB insert | `scheduleForTask()`   |
| `final.tsx` (Update)         | After local DB update | `rescheduleForTask()` |
| `useTaskActions.ts` (Delete) | Before DB deletion    | `cancelForTask()`     |

***

## Bug Fixes

Three subtle bugs were discovered and resolved during implementation:

### 1. DB Path Mismatch

* **Problem:** Module was using `getDatabasePath()` which returned the wrong directory.
* **Fix:** expo-sqlite stores databases at `filesDir/SQLite/`, not the default Android DB path.

### 2. Chain Not Continuing

* **Problem:** `findNextTimeSlot()` kept returning the same window because `endSecs > currentSecs` was true for the currently active window.
* **Fix:** Added an `afterMs` parameter to skip past windows that have already been processed.

### 3. Adjacent Windows Skipped

* **Problem:** A window starting at exactly the previous window's end time was being excluded.
* **Fix:** Changed `<=` to `<` in the comparison so the boundary case is correctly included.

***

## Legacy Cleanup

* **Removed:** Old plugin-based `withAlarmModule/` approach.
* **Removed:** Manual `AlarmPackage` registration from `MainApplication.kt`.
* **Refactored:** `AlarmModule` now uses the modern Expo Modules Kotlin DSL.