{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://spec.rostack.example/rostack_v1/discovery.schema.json",
  "title": "rostack_v1 discovery document",
  "type": "object",
  "additionalProperties": false,
  "required": ["protocol", "implementation", "endpoints", "authentication", "capabilities", "resources"],
  "properties": {
    "protocol": {
      "type": "object",
      "additionalProperties": false,
      "required": ["name", "version"],
      "properties": {
        "name": {"const": "rostack"},
        "version": {"const": "rostack_v1"}
      }
    },
    "implementation": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "name", "api_version"],
      "properties": {
        "id": {"type": "string", "minLength": 1},
        "name": {"type": "string", "minLength": 1},
        "api_version": {"type": "string", "minLength": 1},
        "documentation_url": {"type": "string", "format": "uri"}
      }
    },
    "endpoints": {
      "type": "object",
      "additionalProperties": false,
      "required": ["discovery", "json_api", "websocket"],
      "properties": {
        "discovery": {"type": "string", "format": "uri", "pattern": "^https://"},
        "json_api": {"type": "string", "format": "uri", "pattern": "^https://"},
        "websocket": {"type": "string", "format": "uri", "pattern": "^wss://"}
      }
    },
    "authentication": {
      "type": "object",
      "additionalProperties": false,
      "required": ["methods", "permissions"],
      "properties": {
        "discovery_public": {"type": "boolean", "default": true},
        "methods": {
          "type": "array",
          "minItems": 1,
          "uniqueItems": true,
          "items": {
            "oneOf": [
              {"$ref": "#/$defs/oauth2Authentication"},
              {"$ref": "#/$defs/sharedTokenAuthentication"}
            ]
          }
        },
        "permissions": {
          "type": "object",
          "minProperties": 1,
          "additionalProperties": {"type": "string"}
        }
      }
    },
    "capabilities": {
      "type": "object",
      "additionalProperties": false,
      "required": ["filter_operators", "max_page_size", "websocket"],
      "properties": {
        "filter_operators": {
          "type": "array",
          "uniqueItems": true,
          "items": {"enum": ["eq", "ne", "gt", "gte", "lt", "lte", "in", "nin", "contains", "starts_with", "ends_with", "exists"]}
        },
        "max_page_size": {"type": "integer", "minimum": 1},
        "websocket": {
          "type": "object",
          "additionalProperties": false,
          "required": ["event_encodings", "extensions", "authentication_timeout_ms", "heartbeat_interval_ms", "heartbeat_timeout_ms", "reconnect_min_delay_ms", "reconnect_max_delay_ms", "discovery_refresh_after_ms"],
          "properties": {
            "event_encodings": {
              "type": "array",
              "minItems": 1,
              "uniqueItems": true,
              "contains": {"const": "json"},
              "items": {"enum": ["json", "compact-json"]}
            },
            "extensions": {
              "type": "array",
              "uniqueItems": true,
              "items": {"enum": ["permessage-deflate"]}
            },
            "authentication_timeout_ms": {"type": "integer", "minimum": 1000},
            "heartbeat_interval_ms": {"type": "integer", "minimum": 1000},
            "heartbeat_timeout_ms": {"type": "integer", "minimum": 1000},
            "reconnect_min_delay_ms": {"type": "integer", "minimum": 100},
            "reconnect_max_delay_ms": {"type": "integer", "minimum": 1000},
            "discovery_refresh_after_ms": {"type": "integer", "minimum": 1000}
          }
        }
      }
    },
    "resources": {
      "type": "array",
      "minItems": 1,
      "items": {"$ref": "#/$defs/resource"}
    },
    "alternate_versions": {
      "type": "array",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": ["api_version", "discovery_url"],
        "properties": {
          "api_version": {"type": "string", "minLength": 1},
          "discovery_url": {"type": "string", "format": "uri", "pattern": "^https://"}
        }
      }
    }
  },
  "$defs": {
    "oauth2Authentication": {
      "type": "object",
      "additionalProperties": false,
      "required": ["type", "authorization_server_metadata"],
      "properties": {
        "type": {"const": "oauth2"},
        "authorization_server_metadata": {"type": "string", "format": "uri", "pattern": "^https://"}
      }
    },
    "sharedTokenAuthentication": {
      "type": "object",
      "additionalProperties": false,
      "required": ["type", "http_authorization_scheme", "provisioning"],
      "properties": {
        "type": {"const": "shared_token"},
        "http_authorization_scheme": {"const": "Rostack-Token"},
        "provisioning": {"const": "out_of_band"},
        "description": {"type": "string"}
      }
    },
    "resource": {
      "type": "object",
      "additionalProperties": false,
      "required": ["name", "collection_url", "item_url_template", "representations", "events", "filtering", "read_permissions", "subscribe_permissions"],
      "properties": {
        "name": {"type": "string", "pattern": "^[a-z][a-z0-9-]*$"},
        "description": {"type": "string"},
        "collection_url": {"type": "string", "format": "uri", "pattern": "^https://"},
        "item_url_template": {"type": "string", "pattern": "^https://.*\\{id\\}"},
        "representations": {
          "type": "array",
          "minItems": 1,
          "items": {"$ref": "#/$defs/representation"}
        },
        "events": {
          "type": "array",
          "uniqueItems": true,
          "items": {"$ref": "#/$defs/eventDescriptor"}
        },
        "event_filtering": {"type": "boolean", "default": false},
        "filtering": {"$ref": "#/$defs/filtering"},
        "read_permissions": {
          "type": "array",
          "minItems": 1,
          "uniqueItems": true,
          "items": {"type": "string", "minLength": 1}
        },
        "subscribe_permissions": {
          "type": "array",
          "uniqueItems": true,
          "items": {"type": "string", "minLength": 1}
        }
      }
    },
    "eventDescriptor": {
      "type": "object",
      "additionalProperties": false,
      "required": ["name", "schema_url", "schema_dialect", "state_transition"],
      "properties": {
        "name": {"type": "string", "pattern": "^[a-z][a-z0-9.-]*$"},
        "schema_url": {"type": "string", "format": "uri", "pattern": "^https://"},
        "schema_dialect": {"type": "string", "format": "uri"},
        "description": {"type": "string"},
        "state_transition": {"enum": ["create", "update", "delete"]},
        "tombstone": {"type": "boolean", "default": false}
      }
    },
    "representation": {
      "type": "object",
      "additionalProperties": false,
      "required": ["media_type", "schema_url", "schema_dialect"],
      "properties": {
        "media_type": {"type": "string", "pattern": "^[^/ ]+/[^/ ]+$"},
        "schema_url": {"type": "string", "format": "uri", "pattern": "^https://"},
        "schema_dialect": {"type": "string", "format": "uri"},
        "description": {"type": "string"}
      }
    },
    "filtering": {
      "type": "object",
      "additionalProperties": false,
      "required": ["filterable_fields", "sortable_fields"],
      "properties": {
        "filterable_fields": {
          "type": "object",
          "additionalProperties": {
            "type": "array",
            "minItems": 1,
            "uniqueItems": true,
            "items": {"enum": ["eq", "ne", "gt", "gte", "lt", "lte", "in", "nin", "contains", "starts_with", "ends_with", "exists"]}
          },
          "propertyNames": {"pattern": "^/"}
        },
        "sortable_fields": {
          "type": "array",
          "uniqueItems": true,
          "items": {"type": "string", "pattern": "^/"}
        }
      }
    }
  }
}