syntax = "proto3";

package meshcore.v1;

option go_package = "github.com/corescope/proto/v1";

import "common.proto";

// ═══════════════════════════════════════════════════════════════════════════════
// GET /api/stats — Server-wide statistics
// ═══════════════════════════════════════════════════════════════════════════════

// GET /api/stats — response. Lightweight, cached 10s.
message StatsResponse {
  // Observation count (legacy name, same as totalObservations).
  int32 total_packets = 1 [json_name = "totalPackets"];
  // Unique transmission count (null during startup).
  optional int32 total_transmissions = 2 [json_name = "totalTransmissions"];
  // Total observation records.
  int32 total_observations = 3 [json_name = "totalObservations"];
  // Active nodes (seen in last 7 days).
  int32 total_nodes = 4 [json_name = "totalNodes"];
  // All nodes ever seen.
  int32 total_nodes_all_time = 5 [json_name = "totalNodesAllTime"];
  // Observer device count.
  int32 total_observers = 6 [json_name = "totalObservers"];
  // Observations in the last hour.
  int32 packets_last_hour = 7 [json_name = "packetsLastHour"];
  // Backend engine identifier (always "node" for Node.js, "go" for Go).
  string engine = 8;
  // Application version from package.json (e.g. "2.6.0").
  string version = 9;
  // Git short SHA or "unknown".
  string commit = 10;
  // Per-role active node counts.
  RoleCounts counts = 11;
}

// ═══════════════════════════════════════════════════════════════════════════════
// GET /api/health — Server health and telemetry
// ═══════════════════════════════════════════════════════════════════════════════

// Process memory usage in megabytes.
message MemoryStats {
  // Resident set size (MB).
  double rss = 1;
  // Used heap memory (MB).
  double heap_used = 2 [json_name = "heapUsed"];
  // Total heap size (MB).
  double heap_total = 3 [json_name = "heapTotal"];
  // External memory (MB).
  double external = 4;
}

// Event loop latency percentiles.
message EventLoopStats {
  // Current event loop lag in milliseconds.
  double current_lag_ms = 1 [json_name = "currentLagMs"];
  // Maximum recorded lag (ms).
  double max_lag_ms = 2 [json_name = "maxLagMs"];
  // 50th percentile lag (ms).
  double p50_ms = 3 [json_name = "p50Ms"];
  // 95th percentile lag (ms).
  double p95_ms = 4 [json_name = "p95Ms"];
  // 99th percentile lag (ms).
  double p99_ms = 5 [json_name = "p99Ms"];
}

// Cache performance counters.
message CacheStats {
  // Number of cached entries.
  int32 entries = 1;
  // Cache hit count.
  int32 hits = 2;
  // Cache miss count.
  int32 misses = 3;
  // Stale cache hit count.
  int32 stale_hits = 4 [json_name = "staleHits"];
  // Recomputation count.
  int32 recomputes = 5;
  // Hit rate percentage (0–100).
  double hit_rate = 6 [json_name = "hitRate"];
}

// Cache stats for perf endpoint (slightly different field names).
message PerfCacheStats {
  // Cache size (entry count).
  int32 size = 1;
  int32 hits = 2;
  int32 misses = 3;
  int32 stale_hits = 4 [json_name = "staleHits"];
  int32 recomputes = 5;
  double hit_rate = 6 [json_name = "hitRate"];
}

// WebSocket connection stats.
message WebSocketStats {
  // Connected WebSocket clients.
  int32 clients = 1;
}

// In-memory packet store stats (health endpoint version).
message HealthPacketStoreStats {
  // Loaded transmissions.
  int32 packets = 1;
  // Estimated memory usage (MB).
  double estimated_mb = 2 [json_name = "estimatedMB"];
}

// Health endpoint performance summary.
message HealthPerfStats {
  int32 total_requests = 1 [json_name = "totalRequests"];
  double avg_ms = 2 [json_name = "avgMs"];
  int32 slow_queries = 3 [json_name = "slowQueries"];
  // Last 5 slow queries.
  repeated SlowQuery recent_slow = 4 [json_name = "recentSlow"];
}

// A slow query record.
message SlowQuery {
  // Request path (e.g. "/api/packets").
  string path = 1;
  // Response time in milliseconds.
  double ms = 2;
  // When the query occurred (ISO 8601).
  string time = 3;
  // HTTP response status code.
  int32 status = 4;
}

// GET /api/health — response.
message HealthResponse {
  // Always "ok".
  string status = 1;
  // Backend engine identifier.
  string engine = 2;
  // Application version.
  string version = 3;
  // Git short SHA.
  string commit = 4;
  // Server uptime in seconds.
  double uptime = 5;
  // Human-readable uptime (e.g. "4h 32m").
  string uptime_human = 6 [json_name = "uptimeHuman"];
  // Process memory usage.
  MemoryStats memory = 7;
  // Event loop latency.
  EventLoopStats event_loop = 8 [json_name = "eventLoop"];
  // Cache performance.
  CacheStats cache = 9;
  // WebSocket connections.
  WebSocketStats websocket = 10;
  // Packet store info.
  HealthPacketStoreStats packet_store = 11 [json_name = "packetStore"];
  // Performance summary.
  HealthPerfStats perf = 12;
}

// ═══════════════════════════════════════════════════════════════════════════════
// GET /api/perf — Detailed performance metrics per endpoint
// ═══════════════════════════════════════════════════════════════════════════════

// Per-endpoint performance stats.
message EndpointStats {
  // Number of requests.
  int32 count = 1;
  // Average response time (ms).
  double avg_ms = 2 [json_name = "avgMs"];
  // 50th percentile (ms).
  double p50_ms = 3 [json_name = "p50Ms"];
  // 95th percentile (ms).
  double p95_ms = 4 [json_name = "p95Ms"];
  // Maximum response time (ms).
  double max_ms = 5 [json_name = "maxMs"];
}

// In-memory packet store stats (perf endpoint version — more detail).
message PerfPacketStoreStats {
  // Total loaded transmissions.
  int32 total_loaded = 1 [json_name = "totalLoaded"];
  // Total observation records.
  int32 total_observations = 2 [json_name = "totalObservations"];
  // Evicted packet count.
  int32 evicted = 3;
  // Insert operation count.
  int32 inserts = 4;
  // Query operation count.
  int32 queries = 5;
  // Currently in-memory packet count.
  int32 in_memory = 6 [json_name = "inMemory"];
  // Whether only SQLite is used (no in-memory store).
  bool sqlite_only = 7 [json_name = "sqliteOnly"];
  // Maximum packet capacity.
  int32 max_packets = 8 [json_name = "maxPackets"];
  // Estimated memory usage (MB).
  double estimated_mb = 9 [json_name = "estimatedMB"];
  // Maximum memory budget (MB).
  double max_mb = 10 [json_name = "maxMB"];
  // Index sizes.
  PacketStoreIndexes indexes = 11;
}

// Packet store index counts.
message PacketStoreIndexes {
  int32 by_hash = 1 [json_name = "byHash"];
  int32 by_observer = 2 [json_name = "byObserver"];
  int32 by_node = 3 [json_name = "byNode"];
  int32 advert_by_observer = 4 [json_name = "advertByObserver"];
}

// WAL page counts.
message WalPages {
  int32 total = 1;
  int32 checkpointed = 2;
  int32 busy = 3;
}

// SQLite database stats.
message SqliteStats {
  // Database file size (MB).
  double db_size_mb = 1 [json_name = "dbSizeMB"];
  // WAL file size (MB).
  double wal_size_mb = 2 [json_name = "walSizeMB"];
  // Freelist size (MB).
  double freelist_mb = 3 [json_name = "freelistMB"];
  // WAL page counts (null if unavailable).
  optional WalPages wal_pages = 4 [json_name = "walPages"];
  // Row counts per table.
  SqliteRowCounts rows = 5;
}

// Row counts by table.
message SqliteRowCounts {
  int32 transmissions = 1;
  int32 observations = 2;
  int32 nodes = 3;
  int32 observers = 4;
}

// GET /api/perf — response.
message PerfResponse {
  // Seconds since perf stats were last reset.
  double uptime = 1;
  // Total requests since reset.
  int32 total_requests = 2 [json_name = "totalRequests"];
  // Average response time (ms).
  double avg_ms = 3 [json_name = "avgMs"];
  // Per-endpoint stats, keyed by route path (e.g. "/api/packets").
  map<string, EndpointStats> endpoints = 4;
  // Last 20 queries exceeding 100ms.
  repeated SlowQuery slow_queries = 5 [json_name = "slowQueries"];
  // Cache performance.
  PerfCacheStats cache = 6;
  // Packet store detailed stats.
  PerfPacketStoreStats packet_store = 7 [json_name = "packetStore"];
  // SQLite database stats.
  SqliteStats sqlite = 8;
}