Process Graph Visit Timestamp TODO

[makr-code]

Context

This issue implements the roadmap item 'Process Graph Visit Timestamp TODO' for the network domain. It is sourced from the consolidated roadmap under 🟢 Low Priority — Future (v1.9.0+) and targets milestone v1.8.0.

Primary detail section: WireProtocolServer: ProcessGraph Visit Timestamp TODO

Goal

Deliver the scoped changes for Process Graph Visit Timestamp TODO in src/network/ and complete the linked detail section in a release-ready state for v1.8.0.

Detailed Scope

WireProtocolServer: ProcessGraph Visit Timestamp TODO

Priority: Low
Target Version: v1.8.0

wire_protocol_server.cpp line 2306 has: "TODO: ProcessGraphManager doesn't store individual visit timestamps per node" — the temporal-graph traversal path in the wire server cannot reconstruct visit ordering for graph result pages.

Implementation Notes:

• [ ] Add ProcessGraphVisitLog (map from node ID to std::chrono::system_clock::time_point) to ProcessGraphManager state; update on each traversal step.
• [ ] Expose via ProcessGraphManager::getVisitTimestamp(node_id) for use in the wire protocol server response encoding.
• [ ] Add unit test verifying visit timestamps are populated and ordered correctly across multi-hop traversals.

---

Priority: High
Target Version: v1.7.0

Add WebSocket support for real-time bidirectional communication.

Features:

• WebSocket server for browser-based clients
• Unified protocol (HTTP upgrade to WebSocket)
• Server-push notifications (document changes, query results)
• Streaming query results
• Real-time collaborative editing support

Benefits:

• Enables browser-based real-time applications
• Lower latency than HTTP polling
• Bidirectional communication (server can push to client)
• Compatible with existing web infrastructure

API:

WebSocketServer::Config config;
config.port = 8767;
config.enable_tls = true;
config.max_connections = 10000;
config.enable_compression = true;  // Per-message deflate

WebSocketServer ws_server(config, storage, index_mgr);
ws_server.start();

// Client-side
WebSocketClient client("wss://server.example.com:8767");
client.connect();

// Subscribe to document changes
client.subscribe("documents/articles", [](const auto& change) {
    std::cout << "Document changed: " << change.uuid << std::endl;
});

// Send query, receive streaming results
client.query("FOR doc IN articles FILTER doc.category == 'tech' RETURN doc",
    [](const auto& result) {
        // Called for each result document as it arrives
        std::cout << "Result: " << result << std::endl;
    }
);

Protocol:

WebSocket Frame Format:
┌──────────┬─────────┬──────────┬─────────┐
│ FIN/RSV  │ OpCode  │ Mask     │ Payload │
│ (1 byte) │ (4 bits)│ (1-9 b)  │ (N byte)│
└──────────┴─────────┴──────────┴─────────┘

OpCodes:
- 0x1: Text frame (JSON)
- 0x2: Binary frame (Protobuf)
- 0x8: Close
- 0x9: Ping
- 0xA: Pong

ThemisDB Message Format (JSON):
{
    "id": "req_12345",
    "type": "query" | "subscribe" | "unsubscribe" | "update",
    "payload": { ... }
}

Implementation:

• Use Boost.Beast for WebSocket protocol
• Reuse existing authentication and authorization
• Share storage/index managers with wire protocol server
• Implement backpressure for slow clients

---

Acceptance Criteria

• Add ProcessGraphVisitLog (map from node ID to std::chrono::system_clock::time_point) to ProcessGraphManager state; update on each traversal step.
• Expose via ProcessGraphManager::getVisitTimestamp(node_id) for use in the wire protocol server response encoding.
• Add unit test verifying visit timestamps are populated and ordered correctly across multi-hop traversals.
• WebSocket server for browser-based clients
• Unified protocol (HTTP upgrade to WebSocket)
• Server-push notifications (document changes, query results)
• Streaming query results
• Real-time collaborative editing support
• Enables browser-based real-time applications
• Lower latency than HTTP polling
• Bidirectional communication (server can push to client)
• Compatible with existing web infrastructure
• Use Boost.Beast for WebSocket protocol
• Reuse existing authentication and authorization
• Share storage/index managers with wire protocol server
• Implement backpressure for slow clients

Relationships

• Roadmap row: Implement V1.4.0 alpha: Complete documentation with detailed Mermaid diagrams for LLM features, performance optimizations, and infrastructure enhancements #255 (🟢 Low Priority — Future (v1.9.0+))
• Depends on: none identified during generation.
• Part of: consolidated roadmap delivery tracking.

References

• src/ROADMAP.md
• src/network/FUTURE_ENHANCEMENTS.md#wireprotocolserver-processgraph-visit-timestamp-todo
• Source key: roadmap:255:network:v1.8.0:wireprotocolserver-processgraph-visit-timestamp-todo

Generated from the consolidated source roadmap. Keep the roadmap and issue in sync when scope changes.