allOf:
  - $ref: "tracking_event_base.yml"

  - type: object

    required:
      - type
      - name

    properties:
      type:
        description: a Certified letter tracking event
        type: string
        enum:
          - certified

      name:
        type: string
        enum:
          - Mailed
          - In Transit
          - In Local Area
          - Processed for Delivery
          - Pickup Available
          - Delivered
          - Re-Routed
          - Returned to Sender
          - Issue
        description: >
          Name of tracking event for Certified letters. Letters sent with USPS
          Certified Mail are fully tracked by USPS, therefore their tracking
          events have an additional details object with more detailed
          information about the tracking event. Some certified tracking event names have
          multiple meanings, noted in the list here. See the description of the
          details object for the full set of combined certified tracking event name meanings.

            * `Mailed` - Package has been accepted into the carrier network for delivery.

            * `In Transit` - Maps to four distinct stages of transit.

            * `In Local Area` - Package is at a location near the end destination.

            * `Processed for Delivery` - Maps to two distinct stages of delivery.

            * `Pickup Available` - Package is available for pickup at carrier location.

            * `Delivered` - Package has been delivered.

            * `Re-Routed` - Package has been forwarded.

            * `Returned to Sender` - Package is to be returned to sender.

            * `Issue` - Maps to (at least) 15 possible issues, some of which are actionable.

      details:
        $ref: "tracking_event_details.yml"

      location:
        type: string
        description: >
          The zip code in which the event occurred if it exists, otherwise will
          be the name of a Regional Distribution Center if it exists, otherwise
          will be null.
        nullable: true