{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://gitea.dohertylan.com/dohertj2/3yearplan/raw/branch/main/schemas/format/equipment-class.schema.json",
  "title": "Equipment-Class Template",
  "description": "Declares the canonical raw signal vocabulary for an equipment class. Consumed by OtOpcUa (validates per-equipment tag config), Redpanda (derives Protobuf event schemas), and dbt (derives column definitions for the curated layer).",
  "type": "object",
  "required": ["classId", "version", "displayName", "signals"],
  "additionalProperties": false,
  "properties": {
    "classId": {
      "type": "string",
      "pattern": "^[a-z0-9-_]{1,64}$",
      "description": "Stable logical ID for the class. Lowercase, hyphens, underscores allowed. Once published, never changes — clients pin to it. Convention: `_` prefix indicates an abstract base class (e.g. `_base`) intended only to be extended, not used directly on equipment."
    },
    "extends": {
      "type": ["string", "null"],
      "pattern": "^[a-z0-9-_]{1,64}$",
      "description": "Optional parent class to inherit from. Inherited signals, alarms, and stateModel are merged into this class — the child can add new ones and override individual entries by `name`. The `_base` class (which every equipment template should extend) provides the universal cross-machine metadata (identity, state, alarms, optional production context)."
    },
    "version": {
      "type": "string",
      "pattern": "^[0-9]+\\.[0-9]+\\.[0-9]+$",
      "description": "Semver. Major bump = breaking change; minor = additive non-breaking; patch = doc/clarification only."
    },
    "displayName": {
      "type": "string",
      "minLength": 1,
      "maxLength": 128,
      "description": "Human-readable name (e.g. 'FANUC CNC')."
    },
    "description": {
      "type": "string",
      "maxLength": 1024,
      "description": "Optional longer description."
    },
    "vendor": {
      "type": "string",
      "maxLength": 64,
      "description": "Vendor or family (e.g. 'FANUC', 'Allen-Bradley', 'Siemens')."
    },
    "applicability": {
      "type": "object",
      "description": "When this class applies. Optional; omit for vendor-agnostic classes.",
      "properties": {
        "drivers": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": ["Galaxy", "ModbusTcp", "AbCip", "AbLegacy", "S7", "TwinCat", "Focas", "OpcUaClient"]
          },
          "description": "Which OtOpcUa drivers can populate equipment of this class."
        },
        "models": {
          "type": "array",
          "items": { "type": "string" },
          "description": "Free-text model identifiers (e.g. '0i-F', '30i-B' for FANUC; '1756-L84E' for Logix)."
        }
      },
      "additionalProperties": false
    },
    "signals": {
      "type": "array",
      "minItems": 1,
      "items": { "$ref": "tag-definition.schema.json" },
      "description": "Required signals every equipment of this class must expose. Operator-configured tags in OtOpcUa are validated against this list — missing required signals = config error; extra signals are allowed (operator-extensible)."
    },
    "alarms": {
      "type": "array",
      "items": {
        "type": "object",
        "required": ["alarmId", "displayName", "severity"],
        "additionalProperties": false,
        "properties": {
          "alarmId": { "type": "string", "pattern": "^[a-z0-9-]{1,64}$" },
          "displayName": { "type": "string", "minLength": 1, "maxLength": 128 },
          "severity": { "type": "string", "enum": ["Low", "Medium", "High", "Critical"] },
          "description": { "type": "string", "maxLength": 1024 }
        }
      },
      "description": "Optional canonical alarm definitions for this class."
    },
    "stateModel": {
      "type": "object",
      "description": "Optional declaration of how this class's raw signals derive into the canonical machine-state vocabulary at Layer 3 (System Platform / Ignition). Informational — derivation lives at Layer 3, not in OtOpcUa.",
      "properties": {
        "states": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": ["Running", "Idle", "Faulted", "Starved", "Blocked", "Changeover", "Maintenance", "Setup"]
          }
        },
        "derivationNotes": { "type": "string", "maxLength": 2048 }
      },
      "additionalProperties": false
    }
  }
}