{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://github.com/fallblu/trading-engine/contracts/diagnostic/v1/diagnostic.schema.json",
  "title": "Trading Engine diagnostic contract v1",
  "description": "One stable machine-readable process or file boundary failure.",
  "type": "object",
  "additionalProperties": false,
  "required": ["diagnostic_version", "code", "phase", "message", "context", "cause"],
  "properties": {
    "diagnostic_version": { "const": "1" },
    "code": {
      "enum": [
        "cli.invalid_arguments",
        "input.io",
        "scenario.invalid_json",
        "scenario.invalid",
        "scenario.unsupported_contract",
        "scenario_stream.invalid",
        "scenario_stream.changed",
        "resource.limit",
        "replay.failed",
        "reducer.failed",
        "strategy.invalid_configuration",
        "strategy.protocol",
        "strategy.timeout",
        "strategy.process",
        "strategy.exit",
        "artifact.exists",
        "artifact.io",
        "artifact.state"
      ]
    },
    "phase": {
      "enum": ["cli", "input", "validation", "replay", "reducer", "strategy", "artifact"]
    },
    "message": { "type": "string", "minLength": 1 },
    "context": { "$ref": "#/$defs/context" },
    "cause": {
      "oneOf": [
        { "type": "null" },
        { "$ref": "#/$defs/cause" }
      ]
    }
  },
  "$defs": {
    "canonicalSequence": {
      "type": "string",
      "pattern": "^[1-9][0-9]*$"
    },
    "context": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "json_path": { "type": "string", "minLength": 1 },
        "line": { "type": "integer", "minimum": 1 },
        "sequence": { "$ref": "#/$defs/canonicalSequence" },
        "event_id": { "type": "string", "minLength": 1 },
        "order_id": { "type": "string", "minLength": 1 },
        "causation_ids": {
          "type": "array",
          "uniqueItems": true,
          "items": { "type": "string", "minLength": 1 }
        }
      }
    },
    "cause": {
      "type": "object",
      "additionalProperties": false,
      "required": ["kind", "message"],
      "properties": {
        "kind": { "type": "string", "minLength": 1 },
        "message": { "type": "string" },
        "operation": { "type": "string", "minLength": 1 },
        "target": { "type": "string" }
      }
    }
  }
}