;; Position NFT - SIP-009 NFT for Time-Locked Positions
;; Define NFT trait locally
(define-trait nft-trait
(
(get-last-token-id () (response uint uint))
(get-token-uri (uint) (response (optional (string-ascii 256)) uint))
(get-owner (uint) (response (optional principal) uint))
(transfer (uint principal principal) (response bool uint))
))
;; Token name
(define-non-fungible-token position uint)
;; Storage
(define-data-var last-token-id uint u0)
(define-data-var token-uri (string-ascii 256) "https://timelock-exchange.com/metadata/")
;; Constants
(define-constant CONTRACT_OWNER tx-sender)
(define-constant ERR_NOT_AUTHORIZED (err u401))
(define-constant ERR_NOT_FOUND (err u404))
(define-constant ERR_ALREADY_EXISTS (err u409))
;; SIP-009 Functions
(define-read-only (get-last-token-id)
(ok (var-get last-token-id)))
(define-read-only (get-token-uri (token-id uint))
(ok (some (var-get token-uri))))
(define-read-only (get-owner (token-id uint))
(ok (nft-get-owner? position token-id)))
(define-public (transfer (token-id uint) (sender principal) (recipient principal))
(begin
(asserts! (is-eq tx-sender sender) ERR_NOT_AUTHORIZED)
(nft-transfer? position token-id sender recipient)))
;; Mint function (called by exchange contract)
(define-public (mint (recipient principal))
(let ((token-id (+ (var-get last-token-id) u1)))
(try! (nft-mint? position token-id recipient))
(var-set last-token-id token-id)
(ok token-id)))
;; Burn function (called when position is closed)
(define-public (burn (token-id uint))
(let ((owner (unwrap! (nft-get-owner? position token-id) ERR_NOT_FOUND)))
(asserts! (is-eq tx-sender owner) ERR_NOT_AUTHORIZED)
(nft-burn? position token-id owner)))
;; Admin function to update URI
(define-public (set-token-uri (new-uri (string-ascii 256)))
(begin
(asserts! (is-eq tx-sender CONTRACT_OWNER) ERR_NOT_AUTHORIZED)
(var-set token-uri new-uri)
(ok true)))