# Directory Client Libraries - Implementation Summary

## Overview

Successfully created both TypeScript and Go client libraries for the Distributed Directory Consensus Protocol (NIP-XX), mirroring functionality while following language-specific idioms.

## TypeScript Client (`pkg/protocol/directory-client/`)

### Files Created
- `package.json` - Dependencies and build configuration
- `tsconfig.json` - TypeScript compiler configuration
- `README.md` - Comprehensive documentation with examples
- `DEVELOPMENT.md` - Development guide
- `src/types.ts` - Type definitions (304 lines)
- `src/validation.ts` - Validation functions (265 lines)
- `src/parsers.ts` - Event parsers for all kinds (408 lines)
- `src/identity-resolver.ts` - Identity & delegation management (288 lines)
- `src/helpers.ts` - Utility functions (199 lines)
- `src/index.ts` - Main entry point

### Key Features
- Built on AppleSauce library for Nostr event handling
- Full TypeScript type safety
- RxJS-based observables for event streams
- Real-time identity resolution with live delegate updates
- Trust score calculation
- Replication filtering

### Dependencies
- `applesauce-core`: ^3.0.0
- `rxjs`: ^7.8.1

## Go Client (`pkg/protocol/directory-client/`)

### Files Created
- `doc.go` - Comprehensive package documentation
- `README.md` - Full API reference and usage examples
- `client.go` - Core client functions
- `identity_resolver.go` - Identity resolution (258 lines)
- `trust.go` - Trust calculation & replication filtering (243 lines)
- `helpers.go` - Event collection & trust graph (224 lines)

### Key Features
- Thread-safe with `sync.RWMutex` protection
- Idiomatic Go API design
- No external dependencies (uses standard library + internal packages)
- Memory-efficient caching
- Trust graph construction

### API Surface

**IdentityResolver:**
- `NewIdentityResolver() *IdentityResolver`
- `ProcessEvent(ev *event.E)`
- `ResolveIdentity(pubkey string) string`
- `IsDelegateKey(pubkey string) bool`
- `GetDelegatesForIdentity(identity string) []string`
- `GetIdentityTag(delegate string) (*IdentityTag, error)`
- `FilterEventsByIdentity(events, identity) []*event.E`

**TrustCalculator:**
- `NewTrustCalculator() *TrustCalculator`
- `AddAct(act *TrustAct)`
- `CalculateTrust(pubkey string) float64`
- `GetActiveTrustActs(pubkey string) []*TrustAct`

**ReplicationFilter:**
- `NewReplicationFilter(minTrustScore float64) *ReplicationFilter`
- `AddTrustAct(act *TrustAct)`
- `ShouldReplicate(pubkey string) bool`
- `GetTrustedRelays() []string`
- `FilterEvents(events []*event.E) []*event.E`

**EventCollector:**
- `NewEventCollector(events []*event.E) *EventCollector`
- `RelayIdentities() []*RelayIdentityAnnouncement`
- `TrustActs() []*TrustAct`
- `GroupTagActs() []*GroupTagAct`
- `PublicKeyAdvertisements() []*PublicKeyAdvertisement`

**TrustGraph:**
- `NewTrustGraph() *TrustGraph`
- `BuildTrustGraph(events []*event.E) *TrustGraph`
- `GetTrustedBy(target string) []string`
- `GetTrustTargets(source string) []string`

## Implementation Notes

### TypeScript-Specific Features
- Observable-based event streams with RxJS
- Promise-based async operations
- Optional chaining and nullish coalescing
- Class-based architecture

### Go-Specific Features
- Goroutine-safe with mutexes
- Struct-based API (not classes)
- Multiple return values for error handling
- Zero-dependency beyond internal packages
- Memory-efficient with manual caching control

### Differences from Protocol Package

The client libraries provide **high-level conveniences** over the base protocol package:

**Protocol Package (`pkg/protocol/directory/`):**
- Low-level event parsing
- Event construction
- Message validation
- Tag handling

**Client Libraries:**
- Identity relationship tracking
- Trust score aggregation
- Event filtering & collection
- Replication decision-making
- Trust graph analysis

### Trust Score Calculation

Both implementations use identical weighted averaging:
- High trust: 100 points
- Medium trust: 50 points
- Low trust: 25 points

Expired acts are excluded from calculation.

### Known Limitations

1. **IdentityTag Structure**: The Go implementation currently uses `NPubIdentity` field and maps it as both identity and delegate, as the actual I tag structure in the protocol needs clarification.

2. **GroupTagAct Fields**: The Go struct has `GroupID`, `TagName`, `TagValue`, `Actor` fields which differ from the TypeScript expectation of `targetPubkey` and `groupTag`. Helper functions adapted accordingly.

3. **TypeScript Signature Verification**: Not yet implemented - requires schnorr library integration.

4. **Event Store Integration**: TypeScript uses AppleSauce's EventStore; Go version designed for custom integration.

## Testing Status

- **TypeScript**: Package structure complete, ready for `npm install && npm build`
- **Go**: Successfully compiles with `go build .`, zero errors, one minor efficiency warning

## Next Steps

1. Implement unit tests for both libraries
2. Add integration tests with actual event data
3. Implement schnorr signature verification in TypeScript
4. Clarify and align IdentityTag structure across implementations
5. Add benchmark tests for performance-critical operations
6. Create example applications demonstrating usage

## File Counts

- TypeScript: 10 files (6 source, 4 config/docs)
- Go: 5 files (4 source, 1 doc)
- Total: 15 new files

## Lines of Code

- TypeScript: ~1,800 lines
- Go: ~725 lines
- Total: ~2,525 lines

## Documentation

Both libraries include:
- Comprehensive README with usage examples
- Inline code documentation
- Package-level documentation
- API reference

The implementations successfully mirror each other while respecting language idioms and ecosystem conventions.