{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/SendMessageRequest",
  "title": "SendMessageRequest",
  "type": "object",
  "description": "Request to send a message.",
  "properties": {
    "recipient": {
      "type": "object",
      "description": "Message recipient.",
      "properties": {
        "id": {
          "type": "string",
          "description": "Recipient user ID.",
          "example": "100001234567890"
        }
      },
      "required": [
        "id"
      ]
    },
    "messaging_type": {
      "type": "string",
      "description": "Messaging type.",
      "enum": [
        "RESPONSE",
        "UPDATE",
        "MESSAGE_TAG"
      ],
      "example": "RESPONSE"
    },
    "message": {
      "type": "object",
      "description": "Message content.",
      "properties": {
        "text": {
          "type": "string",
          "description": "Message text.",
          "example": "Hello! How can I help you today?"
        },
        "attachment": {
          "type": "object",
          "description": "Message attachment.",
          "properties": {
            "type": {
              "type": "string",
              "enum": [
                "image",
                "audio",
                "video",
                "file",
                "template"
              ]
            },
            "payload": {
              "type": "object"
            }
          }
        }
      }
    }
  },
  "required": [
    "recipient",
    "messaging_type",
    "message"
  ]
}