type CID string

type Command string

type DID string

# Field requirements:
#
# | Name  |     Delegation      |     Invocation      |  Token   |
# |       | Required | Nullable | Required | Nullable |          |
# | ----- | -------- | -------- | -------- | -------- | -------- |
# | iss   | Yes      | No       | Yes      | No       |          |
# | aud   | Yes      | No       | No       | N/A      | Optional |
# | sub   | Yes      | Yes      | Yes      | No       | Nullable |
# | cmd   | Yes      | No       | Yes      | No       |          |
# | pol   | Yes      | No       | X        | X        | Optional |
# | nonce | Yes      | No       | No       | N/A      | Optional |
# | meta  | No       | N/A      | No       | N/A      | Optional |
# | nbf   | No       | N/A      | X        | X        | Optional |
# | exp   | Yes      | Yes      | Yes      | Yes      | Nullable |
# | args  | X        | X        | Yes      | No       | Optional |
# | prf   | X        | X        | Yes      | No       | Optional |
# | iat   | X        | X        | No       | N/A      | Optional |
# | cause | X        | X        | No       | N/A      | Optional |

type Token struct {
    # Issuer DID (sender)
    issuer DID (rename "iss")
    # Audience DID (receiver)
    audience optional DID (rename "aud")
    # Principal that the chain is about (the Subject)
    subject nullable DID (rename "sub")

    # The Command to eventually invoke
    command Command (rename "cmd")

    # The delegation policy
    # It doesn't seem possible to represent it with a schema.
    policy optional Any (rename "pol")

    # The invocation's arguments
    arguments optional {String: Any} (rename "args")

    # Delegations that prove the chain of authority
    Proofs optional [CID] (rename "prf")

    # A unique, random nonce
    nonce optional Bytes
    
    # Arbitrary Metadata
    meta optional {String : Any}

    # "Not before" UTC Unix Timestamp in seconds (valid from), 53-bits integer
    notBefore optional Int (rename "nbf")
    # The timestamp at which the delegation becomes invalid
    expiration nullable Int (rename "exp")
    # The timestamp at which the invocation was created
    issuedAt optional Int

    # An optional CID of the receipt that enqueued this invocation
    cause optional CID
}