syntax = "proto3";
option csharp_namespace = "ScadaLink.Communication.Grpc";
package sitestream;

import "google/protobuf/timestamp.proto";
import "google/protobuf/wrappers.proto";   // Int32Value

service SiteStreamService {
  rpc SubscribeInstance(InstanceStreamRequest) returns (stream SiteStreamEvent);
  rpc IngestAuditEvents(AuditEventBatch) returns (IngestAck);
  rpc IngestCachedTelemetry(CachedTelemetryBatch) returns (IngestAck);
  rpc PullAuditEvents(PullAuditEventsRequest) returns (PullAuditEventsResponse);
}

message InstanceStreamRequest {
  string correlation_id = 1;
  string instance_unique_name = 2;
}

message SiteStreamEvent {
  string correlation_id = 1;
  oneof event {
    AttributeValueUpdate attribute_changed = 2;
    AlarmStateUpdate alarm_changed = 3;
  }
}

enum Quality {
  QUALITY_UNSPECIFIED = 0;
  QUALITY_GOOD = 1;
  QUALITY_UNCERTAIN = 2;
  QUALITY_BAD = 3;
}

enum AlarmStateEnum {
  ALARM_STATE_UNSPECIFIED = 0;
  ALARM_STATE_NORMAL = 1;
  ALARM_STATE_ACTIVE = 2;
}

// Severity level for an active alarm. Binary trigger types (ValueMatch,
// RangeViolation, RateOfChange) always emit ALARM_LEVEL_NONE. The HiLo
// trigger type emits one of the directional values.
enum AlarmLevelEnum {
  ALARM_LEVEL_NONE = 0;
  ALARM_LEVEL_LOW = 1;
  ALARM_LEVEL_LOW_LOW = 2;
  ALARM_LEVEL_HIGH = 3;
  ALARM_LEVEL_HIGH_HIGH = 4;
}

message AttributeValueUpdate {
  string instance_unique_name = 1;
  string attribute_path = 2;
  string attribute_name = 3;
  string value = 4;
  Quality quality = 5;
  google.protobuf.Timestamp timestamp = 6;
}

message AlarmStateUpdate {
  string instance_unique_name = 1;
  string alarm_name = 2;
  AlarmStateEnum state = 3;
  int32 priority = 4;
  google.protobuf.Timestamp timestamp = 5;
  AlarmLevelEnum level = 6;  // ALARM_LEVEL_NONE for binary trigger types; set by HiLo.
  string message = 7;        // Optional per-band operator message; empty when unset.
}

// Audit Log (#23) telemetry: single lifecycle event ferried from a site SQLite
// hot-path row to central via IngestAuditEvents. Mirrors AuditEvent (Commons)
// minus the site-local ForwardState and the central IngestedAtUtc (set on ingest).
message AuditEventDto {
  string event_id = 1;
  google.protobuf.Timestamp occurred_at_utc = 2;
  string channel = 3;
  string kind = 4;
  string correlation_id = 5;      // empty string represents null
  string source_site_id = 6;
  string source_instance_id = 7;
  string source_script = 8;
  string actor = 9;
  string target = 10;
  string status = 11;
  google.protobuf.Int32Value http_status = 12;     // null when absent
  google.protobuf.Int32Value duration_ms = 13;
  string error_message = 14;
  string error_detail = 15;
  string request_summary = 16;
  string response_summary = 17;
  bool payload_truncated = 18;
  string extra = 19;
}

message AuditEventBatch { repeated AuditEventDto events = 1; }
message IngestAck { repeated string accepted_event_ids = 1; }

// Audit Log (#23) M3 cached-call combined telemetry: a single packet carries
// both the AuditEvent row to insert and the SiteCalls operational-state upsert
// for one lifecycle event of a cached outbound call. Central writes both rows
// in one MS SQL transaction so the audit and operational mirrors never drift.
message SiteCallOperationalDto {
  string tracked_operation_id = 1;       // GUID string ("D" format)
  string channel = 2;                    // "ApiOutbound" | "DbOutbound"
  string target = 3;
  string source_site = 4;
  string status = 5;                     // AuditStatus name
  int32 retry_count = 6;
  string last_error = 7;                 // empty when null
  google.protobuf.Int32Value http_status = 8;
  google.protobuf.Timestamp created_at_utc = 9;
  google.protobuf.Timestamp updated_at_utc = 10;
  google.protobuf.Timestamp terminal_at_utc = 11;  // absent when not terminal
}

message CachedTelemetryPacket {
  AuditEventDto audit_event = 1;
  SiteCallOperationalDto operational = 2;
}

message CachedTelemetryBatch { repeated CachedTelemetryPacket packets = 1; }

// Audit Log (#23) M6 reconciliation pull: central→site request for any
// site-local AuditLog rows with OccurredAtUtc >= since_utc that have not yet
// been ingested centrally (ForwardState in {Pending, Forwarded}). The site
// flips returned rows to Reconciled after the response is on the wire.
// more_available signals batch_size was saturated so the caller knows to
// issue a follow-up pull with an advanced since_utc cursor.
message PullAuditEventsRequest {
  google.protobuf.Timestamp since_utc = 1;
  int32 batch_size = 2;
}

message PullAuditEventsResponse {
  repeated AuditEventDto events = 1;
  bool more_available = 2;
}