{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://gentifi.com/standards/collections-0.1.schema.json",
  "title": "Collection (draft 0.1)",
  "description": "Draft extension to discovery catalogues such as ARD's ai-catalog.json: one document that describes a group of businesses (an event, a place, an association or a marketplace). Proposal for discussion, not a standard. Field names are illustrative and may change.",
  "type": "object",
  "required": ["collection"],
  "properties": {
    "collection": { "$ref": "#/$defs/collection" }
  },
  "$defs": {
    "collection": {
      "type": "object",
      "required": ["id", "name", "kind", "publisher", "members"],
      "properties": {
        "id": {
          "type": "string",
          "pattern": "^[a-z0-9][a-z0-9-]*$",
          "description": "Stable identifier, unique within the publisher's domain."
        },
        "name": { "type": "string", "minLength": 1 },
        "kind": {
          "enum": ["event", "place", "association", "marketplace"],
          "description": "Type of group."
        },
        "publisher": {
          "type": "object",
          "required": ["name", "domain"],
          "properties": {
            "name": { "type": "string", "minLength": 1 },
            "domain": {
              "type": "string",
              "format": "hostname",
              "description": "Domain the publisher controls. Clients verify the collection is served from it."
            }
          }
        },
        "validFrom": { "type": "string", "format": "date", "description": "Start of the time window, for events." },
        "validTo": { "type": "string", "format": "date", "description": "End of the time window. Members stay reachable afterwards through their own catalogues." },
        "area": {
          "type": "object",
          "description": "Geography, for places.",
          "properties": {
            "postcodeAreas": { "type": "array", "items": { "type": "string" } },
            "boundary": { "type": "string", "format": "uri", "description": "URL of a GeoJSON boundary." }
          }
        },
        "facets": {
          "type": "array",
          "items": { "type": "string" },
          "description": "Member fields agents can filter by, such as category, priceFrom or stand."
        },
        "members": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/member" }
        }
      }
    },
    "member": {
      "type": "object",
      "description": "A member business, pointing to its own catalogue, or a nested collection.",
      "properties": {
        "catalog": { "type": "string", "format": "uri", "pattern": "^https://" },
        "collection": { "type": "string", "format": "uri", "pattern": "^https://" },
        "role": {
          "type": "object",
          "description": "The member's place in the collection, such as stand number, category or sponsor tier.",
          "additionalProperties": true
        }
      },
      "oneOf": [
        { "required": ["catalog"] },
        { "required": ["collection"] }
      ]
    }
  }
}