# Message Segmentation 

Split large payloads into Waku-sized segments with optional Reed–Solomon parity for robust reconstruction. Inbound segmented messages are reassembled and persisted until complete.

## Features

- **Segmentation**: Outbound payloads over the configured size are split into segments; smaller payloads pass through unchanged.
- **Reconstruction**: Inbound segments can be processed out of order and reassembled into the original message.
- **Erasure coding**: Adds parity segments at 12.5% of data segments (≤ SegmentsReedsolomonMaxCount), enabling recovery with ~87.5% of segments.
- **Persistence**: Segments and completion state are stored (SQLite) and survive restarts.
- **API simplicity**: Main parameter is the maximum segment size; inject your persistence object.

## Essential API

- **Types**: `SegmentationHander`, `Chunk`, `Message`
- **Outbound**: `segmentMessage(handler, chunk: Chunk): Result[seq[Chunk], string]`
- **Inbound**: `handleSegmentationLayer(handler, message: var Message): Result[void, string]`
- **Helpers**: `isParityMessage(segment: SegmentMessage): bool`

Notes
- Parity rate is 12.5% (`SegmentsParityRate = 0.125`).

## Wire format

Segments are protobuf-encoded (`segment_message.proto`):

## Tests

See `tests/test_segmentation.nim` for examples covering in-order/out-of-order and parity recovery paths.