{
    "$id": "https://github.com/open-voice-interoperability/docs/tree/main/schemas/conversation-envelope/1.0.2/dialog-event-schema.json",
    "$schema": "https://openvoicenetwork.org/schema",
    "description": "A representation of a 'language event’ that is to say any information associated with a phrase, utterance or part of an utterance.",
    "type": "object",
    "required":  ["id" , "speakerUri", "span", "features" ],
    "properties": {
      "id": {
        "type": "string"
      },
      "previousId": {
        "type": "string"
      },
      "speakerUri": {
        "type": "string"
      },
      "span": { "$ref": "#/$defs/span" },
      "features": {
        "type": "object",
        "patternProperties": {
          ".*": { "$ref": "#/$defs/features" }
        }
      }
    },
    "$defs": {
      "features": {
        "type": "object",
        "required":  ["mimeType" , "tokens" ],
        "properties": {
          "encoding": {
            "type": "string",
            "description": "The text encoding of the token values"
          },
          "mimeType": {
            "type": "string",
            "description": "The mimeType of the token values"
          },
          "lang": {
            "type": "string",
            "description": "The language of the token values"
          },
          "tokenSchema": {
            "type": "string",
            "description": "A schema restricting the token values"
          },
          "tokens" : {
            "type": "array",
            "items":  { 
                "$ref": "#/$defs/token" 
            },
          "alternates": {
            "type": "array", 
            "items": {
              "type": "array",
                "items": {
                  "type": "object",
                  "$ref": "#/$defs/token" 
                }
              }
            }
          }
        }
      },
      "token": {
        "type": "object",
        "anyOf": [
          { "required": ["value"] },
          { "required": ["valueUrl"] }
        ],
        "properties": {
            "value": {
              "type": ["number","string","object","array","boolean"]
            },
            "valueUrl": {
              "$ref": "#/$defs/url"
            },          
            "confidence": {
              "type": "number"
            },
            "span": { "$ref": "#/$defs/span" },
            "links" : {
                "type": "array",
                "items":  { 
                  "$ref": "#/$defs/jsonpath" 
                }
            }
        }
      },
      "url": {
        "type": "string",
        "description": "Any valid URL"
      },
      "jsonpath": {
        "type": "string",
        "description": "an expression in JSON Path syntax"
      },
      "span": {
        "anyOf": [
          { "required": ["startTime"] },
          { "required": ["startOffset"] }
        ],
        "properties": {
          "startTime": { 
              "$ref": "#/$defs/isoTime" 
          },
          "endTime": { 
              "$ref": "#/$defs/isoTime" 
          },
          "startOffset": {
              "$ref": "#/$defs/isoDuration" 
          },
          "endOffset": {
              "$ref": "#/$defs/isoDuration" 
          }
        }
      },
      "isoTime": {        
        "description": "A string in ISO 8601 absolute format."
      },
      "isoDuration": {        
        "description": "A string in ISO 8601 duration format."
      }
    }
}