## Reconciliation

**Path:** `src/reconciliation/reconciliation.ts`  
**Export:** `StateReconciliation`

### What it does

Client-side prediction and server reconciliation for multiplayer games. Buffers inputs and server states, detects mispredictions, and smoothly reconciles client state.

### Key API

| Method | Description |
|--------|-------------|
| `processInput(input, timestamp)` | Buffer a player input, return sequence |
| `predictClientState(state, applyPhysics, deltaTime)` | Apply unprocessed inputs locally |
| `processServerUpdate(state, sequence, timestamp)` | Receive server-authoritative state |
| `reconcileState(state, applyPhysics)` | Rewind + replay after server correction |
| `extrapolateState(state, deltaTime)` | Predict forward for missing server data |
| `sendPing()` / `receivePong()` | Latency measurement |

### Buffers

- **Input buffer** — stores client inputs with sequence numbers
- **State buffer** — stores predicted and server states
- **Jitter buffer** — optional delay for out-of-order server packets

### Reconciliation Flow

1. Client predicts state from inputs
2. Server sends authoritative state
3. If prediction error > threshold, reconcile:
   - Find server state in buffer
   - Rewind to server state
   - Replay all inputs after that point
   - Smoothly interpolate to reconciled state

### Depends on

- `../types.js` — `PlayerState`, `PlayerInput`, `ReconciliationOptions`
- `../prediction/` — `PositionPredictor`
- `../interpolation/` — `GameInterpolator`