FirstNFT

  (define-trait nft-trait
  (
    ;; Last token ID, limited to uint range
    (get-last-token-id () (response uint uint))

    ;; URI for metadata associated with the token
    (get-token-uri (uint) (response (optional (string-ascii 256)) uint))

     ;; Owner of a given token identifier
    (get-owner (uint) (response (optional principal) uint))

    ;; Transfer from the sender to a new principal
    (transfer (uint principal principal) (response bool uint))
  )
)

(define-non-fungible-token amazing-aardvarks uint)

(define-data-var last-token-id uint u0)

(define-constant contract-owner tx-sender)
(define-constant err-owner-only (err u100))
(define-constant err-not-token-owner (err u101))

(define-read-only (get-last-token-id)
    (ok (var-get last-token-id))
)

(define-read-only (get-token-uri (token-id uint))
    (ok none)
)

(define-read-only (get-owner (token-id uint))
    (ok (nft-get-owner? amazing-aardvarks token-id))
)

(define-public (transfer (token-id uint) (sender principal) (recipient principal))
    (begin
        (asserts! (is-eq tx-sender sender) err-not-token-owner)
        (nft-transfer? amazing-aardvarks token-id sender recipient)
    )
)

(define-public (mint (recipient principal))
    (let
        (
            (token-id (+ (var-get last-token-id) u1))
        )
        (asserts! (is-eq tx-sender contract-owner) err-owner-only)
        (try! (nft-mint? amazing-aardvarks token-id recipient))
        (var-set last-token-id token-id)
        (ok token-id)
    )
)