# Dispatch & Events

`src/dispatch/` — Task and phase dispatch queues. `src/events/` — Typed event bus.

## Event Bus

`src/events/` — Typed pub/sub system for inter-module communication.

### Architecture
- **Port**: `EventBus` interface with `emit(event)` and `on(type, handler)`
- **Adapter**: `TypedEventBus` using Node.js `EventEmitter`
- All events implement `BaseEvent { type, timestamp, payload }`

### Event Types (48)

| Category | Events | Count |
|----------|--------|-------|
| **Agent** | `agent:spawned`, `agent:stopped`, `agent:crashed`, `agent:resumed`, `agent:account_switched`, `agent:deleted`, `agent:waiting`, `agent:output` | 8 |
| **Task** | `task:queued`, `task:dispatched`, `task:completed`, `task:blocked`, `task:pending_approval` | 5 |
| **Phase** | `phase:queued`, `phase:started`, `phase:completed`, `phase:blocked` | 4 |
| **Merge** | `merge:queued`, `merge:started`, `merge:completed`, `merge:conflicted` | 4 |
| **Page** | `page:created`, `page:updated`, `page:deleted` | 3 |
| **Process** | `process:spawned`, `process:stopped`, `process:crashed` | 3 |
| **Server** | `server:started`, `server:stopped` | 2 |
| **Worktree** | `worktree:created`, `worktree:removed`, `worktree:merged`, `worktree:conflict` | 4 |
| **Account** | `account:credentials_refreshed`, `account:credentials_expired`, `account:credentials_validated` | 3 |
| **Log** | `log:entry` | 1 |

### Key Event Payloads

```typescript
AgentSpawnedEvent    { agentId, name, taskId, worktreeId, provider }
AgentStoppedEvent    { agentId, name, taskId, reason }
  // reason: 'user_requested'|'task_complete'|'error'|'waiting_for_input'|
  //         'context_complete'|'breakdown_complete'|'decompose_complete'|'refine_complete'
AgentWaitingEvent    { agentId, name, taskId, sessionId, questions[] }
AgentOutputEvent     { agentId, stream, data }
TaskCompletedEvent   { taskId, agentId, success, message }
TaskQueuedEvent      { taskId, priority, dependsOn[] }
PhaseStartedEvent    { phaseId, initiativeId }
MergeConflictedEvent { taskId, agentId, worktreeId, targetBranch, conflictingFiles[] }
AccountCredentialsRefreshedEvent { accountId, expiresAt, previousExpiresAt? }
```

## Task Dispatch

`src/dispatch/` — In-memory queue with dependency-ordered dispatch.

### Architecture
- **Port**: `DispatchManager` interface
- **Adapter**: `DefaultDispatchManager`

### How Task Dispatch Works

1. **Queue** — `queue(taskId)` fetches task dependencies, adds to internal Map
2. **Dispatch** — `dispatchNext()` finds highest-priority task with all deps complete
3. **Priority order**: high > medium > low, then oldest first (FIFO within priority)
4. **Checkpoint skip** — Tasks with type starting with `checkpoint:` skip auto-dispatch
5. **Approval check** — `completeTask()` checks `requiresApproval` (task-level, then initiative-level)
6. **Approval flow** — If approval required: status → `pending_approval`, emit `task:pending_approval`

### DispatchManager Methods

| Method | Purpose |
|--------|---------|
| `queue(taskId)` | Add task to dispatch queue |
| `dispatchNext()` | Find and dispatch next ready task |
| `getNextDispatchable()` | Get next task without dispatching |
| `completeTask(taskId, agentId?)` | Complete with approval check |
| `approveTask(taskId)` | Approve pending task |
| `blockTask(taskId, reason)` | Block task with reason |
| `getQueueState()` | Return queued, ready, blocked tasks |

## Phase Dispatch

`DefaultPhaseDispatchManager` — Same pattern for phases:

1. **Queue** — `queuePhase(phaseId)` validates phase is approved, gets dependencies
2. **Dispatch** — `dispatchNextPhase()` finds phase with all deps complete
3. **Auto-queue tasks** — When phase starts, all pending tasks are queued
4. **Events** — `phase:queued`, `phase:started`, `phase:completed`, `phase:blocked`

### PhaseDispatchManager Methods

| Method | Purpose |
|--------|---------|
| `queuePhase(phaseId)` | Queue approved phase |
| `dispatchNextPhase()` | Start next ready phase, auto-queue its tasks |
| `getNextDispatchablePhase()` | Get next phase without dispatching |
| `completePhase(phaseId)` | Mark phase complete |
| `blockPhase(phaseId, reason)` | Block phase |
| `getPhaseQueueState()` | Return queued, ready, blocked phases |