{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Send Invitation Command Schema",
  "description": "Schema for the SendInvitation command that represents the intent to send a screening invitation to a participant",
  "type": "object",
  "required": [
    "participantId",
    "programId",
    "invitationType",
    "communicationPreferences",
    "sentBy",
    "sentAt"
  ],
  "properties": {
    "participantId": {
      "type": "string",
      "description": "Unique identifier for the participant"
    },
    "programId": {
      "type": "string",
      "description": "Unique identifier for the screening program"
    },
    "invitationType": {
      "type": "string",
      "enum": ["INITIAL", "RECALL", "FOLLOW_UP", "REINVITATION", "REMINDER"],
      "description": "Type of screening invitation"
    },
    "communicationPreferences": {
      "type": "object",
      "required": ["preferredChannel", "language"],
      "properties": {
        "preferredChannel": {
          "type": "string",
          "enum": ["EMAIL", "SMS", "POST", "PORTAL"],
          "description": "Preferred communication channel"
        },
        "language": {
          "type": "string",
          "description": "Preferred language for communication"
        },
        "format": {
          "type": "string",
          "enum": ["PLAIN_TEXT", "HTML", "PDF"],
          "description": "Preferred format for the invitation"
        }
      },
      "description": "Participant's communication preferences"
    },
    "sentBy": {
      "type": "string",
      "description": "Identifier of the person sending the invitation"
    },
    "sentAt": {
      "type": "string",
      "format": "date-time",
      "description": "ISO 8601 timestamp when the invitation is being sent"
    },
    "eligibilityDetails": {
      "type": "object",
      "required": ["isEligible", "eligibilityDate"],
      "properties": {
        "isEligible": {
          "type": "boolean",
          "description": "Whether the participant is eligible for screening"
        },
        "eligibilityDate": {
          "type": "string",
          "format": "date-time",
          "description": "Date when eligibility was determined"
        },
        "eligibilityCriteria": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "List of eligibility criteria met"
        }
      },
      "description": "Details about participant eligibility"
    },
    "appointmentPreferences": {
      "type": "object",
      "properties": {
        "preferredDays": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": [
              "MONDAY",
              "TUESDAY",
              "WEDNESDAY",
              "THURSDAY",
              "FRIDAY",
              "SATURDAY",
              "SUNDAY"
            ]
          },
          "description": "Preferred days of the week"
        },
        "preferredTimes": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": ["MORNING", "AFTERNOON", "EVENING"]
          },
          "description": "Preferred times of day"
        },
        "maxTravelDistance": {
          "type": "integer",
          "minimum": 0,
          "description": "Maximum travel distance in kilometers"
        }
      },
      "description": "Participant's appointment preferences"
    },
    "accessibilityNeeds": {
      "type": "array",
      "items": {
        "type": "string",
        "enum": ["WHEELCHAIR_ACCESS", "SIGN_LANGUAGE", "HEARING_LOOP", "NONE"]
      },
      "description": "List of accessibility requirements"
    },
    "invitationContent": {
      "type": "object",
      "required": ["templateId", "variables"],
      "properties": {
        "templateId": {
          "type": "string",
          "description": "Identifier of the invitation template to use"
        },
        "variables": {
          "type": "object",
          "description": "Variables to be used in the template"
        }
      },
      "description": "Content configuration for the invitation"
    },
    "responseDeadline": {
      "type": "string",
      "format": "date-time",
      "description": "Deadline for responding to the invitation"
    },
    "priorityLevel": {
      "type": "string",
      "enum": ["STANDARD", "HIGH", "URGENT"],
      "description": "Priority level for this invitation"
    },
    "attachments": {
      "type": "array",
      "items": {
        "type": "object",
        "required": ["type", "content"],
        "properties": {
          "type": {
            "type": "string",
            "enum": [
              "INFORMATION_SHEET",
              "CONSENT_FORM",
              "PREPARATION_GUIDE",
              "OTHER"
            ],
            "description": "Type of attachment"
          },
          "content": {
            "type": "string",
            "description": "Content or reference to the attachment"
          }
        }
      },
      "description": "Additional documents to be sent with the invitation"
    },
    "notes": {
      "type": "string",
      "description": "Additional notes about sending the invitation"
    }
  }
}