{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://bpa.local/schemas/workflow/v1alpha1",
  "title": "BPA Workflow",
  "type": "object",
  "additionalProperties": false,
  "required": ["apiVersion", "kind", "metadata", "spec"],
  "properties": {
    "apiVersion": { "const": "bpa/v1alpha1" },
    "kind": { "const": "Workflow" },
    "metadata": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "version", "title"],
      "properties": {
        "id": { "$ref": "#/$defs/assetId" },
        "version": { "$ref": "#/$defs/semver" },
        "title": { "type": "string", "minLength": 1, "maxLength": 200 },
        "description": { "type": "string", "maxLength": 4000 }
      }
    },
    "spec": {
      "type": "object",
      "additionalProperties": false,
      "required": ["riskLevel", "inputSchema", "outputSchema", "start", "nodes"],
      "properties": {
        "riskLevel": { "enum": ["R0", "R1", "R2", "R3", "R4"] },
        "inputSchema": { "$ref": "#/$defs/jsonSchema" },
        "outputSchema": { "$ref": "#/$defs/jsonSchema" },
        "start": { "$ref": "#/$defs/nodeKey" },
        "nodes": {
          "type": "object",
          "minProperties": 1,
          "maxProperties": 500,
          "propertyNames": { "$ref": "#/$defs/nodeKey" },
          "additionalProperties": { "$ref": "#/$defs/workflowNode" }
        }
      }
    }
  },
  "$defs": {
    "assetId": {
      "type": "string",
      "pattern": "^[a-z][a-z0-9]*(?:[._-][a-z0-9]+)*$",
      "maxLength": 160
    },
    "nodeKey": {
      "type": "string",
      "pattern": "^[a-z][a-z0-9_]*$",
      "maxLength": 100
    },
    "semver": {
      "type": "string",
      "pattern": "^(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(?:-[0-9A-Za-z.-]+)?$"
    },
    "nodeRef": {
      "type": "string",
      "pattern": "^[a-z][a-z0-9]*(?:[._-][a-z0-9]+)*@(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(?:-[0-9A-Za-z.-]+)?$",
      "maxLength": 200
    },
    "duration": {
      "type": "string",
      "pattern": "^[1-9][0-9]*(?:ms|s|m)$"
    },
    "jsonSchema": {
      "type": "object"
    },
    "transitionMap": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "success": { "$ref": "#/$defs/nodeKey" },
        "failure": { "$ref": "#/$defs/nodeKey" },
        "timeout": { "$ref": "#/$defs/nodeKey" },
        "cancelled": { "$ref": "#/$defs/nodeKey" },
        "uncertain": { "$ref": "#/$defs/nodeKey" }
      }
    },
    "retry": {
      "type": "object",
      "additionalProperties": false,
      "required": ["maxAttempts"],
      "properties": {
        "maxAttempts": { "type": "integer", "minimum": 1, "maximum": 10 },
        "backoff": { "$ref": "#/$defs/duration" },
        "retryableErrors": {
          "type": "array",
          "uniqueItems": true,
          "maxItems": 50,
          "items": { "type": "string", "pattern": "^[A-Z][A-Z0-9_]+$" }
        }
      }
    },
    "workflowNode": {
      "type": "object",
      "additionalProperties": false,
      "required": ["use"],
      "properties": {
        "use": { "$ref": "#/$defs/nodeRef" },
        "with": {},
        "next": { "$ref": "#/$defs/nodeKey" },
        "on": { "$ref": "#/$defs/transitionMap" },
        "timeout": { "$ref": "#/$defs/duration" },
        "retry": { "$ref": "#/$defs/retry" },
        "timing": {
          "$ref": "https://bpa.local/schemas/timing-policy/v1"
        },
        "condition": { "type": "string", "minLength": 1, "maxLength": 1000 },
        "description": { "type": "string", "maxLength": 1000 }
      }
    }
  }
}