# Ledger Projections

## Module
Findings

## Status
IMPLEMENTED

## Description
Projection worker that materializes event streams into queryable read models.

## Implementation Details
- **Ledger Projection Worker**: `src/Findings/StellaOps.Findings.Ledger/Infrastructure/Projection/LedgerProjectionWorker.cs` -- background worker that consumes ledger event streams and materializes them into queryable projection read models.
- **Ledger Projection Reducer**: `src/Findings/StellaOps.Findings.Ledger/Services/LedgerProjectionReducer.cs` -- reduces event sequences into projection state, applying each event to build the current finding state from its event history.
- **Projection Models**: `src/Findings/StellaOps.Findings.Ledger/Domain/ProjectionModels.cs` -- read-side projection models materialized from events (finding state, VEX status, scoring state).
- **Projection Hashing**: `src/Findings/StellaOps.Findings.Ledger/Hashing/ProjectionHashing.cs` -- computes deterministic hashes of projection state for consistency verification between replays.
- **Finding Projection Repository Interface**: `src/Findings/StellaOps.Findings.Ledger/Infrastructure/IFindingProjectionRepository.cs` -- persistence contract for materialized projections.
- **Postgres Finding Projection Repository**: `src/Findings/StellaOps.Findings.Ledger/Infrastructure/Postgres/PostgresFindingProjectionRepository.cs` -- PostgreSQL persistence for projection read models.
- **Tests**: `src/Findings/__Tests/StellaOps.Findings.Ledger.Tests/LedgerProjectionReducerTests.cs`, `src/Findings/StellaOps.Findings.Ledger.Tests/ProjectionHashingTests.cs`

## E2E Test Plan
- [ ] Submit a sequence of finding events (create, update VEX, add attestation) and verify the projection worker materializes the final finding state with correct VEX status and attestation references
- [ ] Verify projection consistency: replay the same event sequence twice and confirm the projection hashes match (deterministic projection)
- [ ] Verify projection catch-up: stop the projection worker, submit events, restart the worker, and confirm it processes all missed events and reaches the correct state
- [ ] Verify the projection reducer correctly handles out-of-order event delivery by ordering events by sequence number before applying
- [ ] Query the materialized projection via the finding query endpoints and verify the response matches the expected state from the event history