(use-trait fungible-token 'SP3FBR2AGK5H9QBDH3EEN6DF8EK8JY7RX8QJ5SVTE.sip-010-trait-ft-standard.sip-010-trait)
;; The road to prosperity is often a roundabout journey, where detours and indirect routes reveal the most valuable insights and innovations.
(define-constant THIS-CONTRACT (as-contract tx-sender))
;; Define the two allowed fee contracts
(define-constant YIN-FEES .yin)
(define-constant YANG-FEES .yang)
;; the fee structure is defined by the calling client
(define-trait fees-trait
((get-fees (uint) (response uint uint))
(hold-fees (uint) (response bool uint))
(release-fees (uint) (response bool uint))
(pay-fees (uint) (response bool uint))))
(define-map swaps uint {ustx: uint, stx-sender: principal, amount: uint, ft-sender: (optional principal), open: bool, ft: principal, fees: principal})
(define-data-var next-id uint u0)
;; read-only function to get swap details by id
(define-read-only (get-swap (id uint))
(match (map-get? swaps id)
swap (ok swap)
(err ERR_INVALID_ID)))
;; helper function to transfer stx to a principal with memo
(define-private (stx-transfer-to (ustx uint) (to principal) (memo (buff 34)))
(contract-call? 'SP3FBR2AGK5H9QBDH3EEN6DF8EK8JY7RX8QJ5SVTE.send-many-memo send-many
(list {to: to,
ustx: ustx,
memo: memo})))
(define-private (is-valid-fees (fees <fees-trait>))
(or (is-eq (contract-of fees) YIN-FEES)
(is-eq (contract-of fees) YANG-FEES)))
;; create a swap between btc and fungible token
(define-public (offer (ustx uint) (amount uint) (ft-sender (optional principal)) (ft <fungible-token>) (fees <fees-trait>))
(let ((id (var-get next-id)))
(asserts! (is-valid-fees fees) ERR_INVALID_FEES)
(asserts! (map-insert swaps id
{ustx: ustx, stx-sender: tx-sender, amount: amount, ft-sender: ft-sender,
open: true, ft: (contract-of ft), fees: (contract-of fees)}) ERR_INVALID_ID)
(print
{
type: "offer",
swap_type: "STX-FT",
contract_address: THIS-CONTRACT,
swap-id: id,
creator: tx-sender,
counterparty: ft-sender,
open: true,
fees: (contract-of fees),
in_contract: "STX",
in_amount: ustx,
in_decimals: u6,
out_contract: (contract-of ft),
out-amount: amount,
out-decimals: (unwrap! (contract-call? ft get-decimals) ERR_FT_FAILURE),
}
)
(var-set next-id (+ id u1))
(try! (contract-call? fees hold-fees ustx))
(match (stx-transfer-to ustx (as-contract tx-sender) 0x636174616d6172616e2073776170)
success (ok id)
error (err (* error u100)))))
;; only stx-sender can cancel the swap after and get the fees back
(define-public (cancel (id uint) (ft <fungible-token>) (fees <fees-trait>))
(let ((swap (unwrap! (map-get? swaps id) ERR_INVALID_ID))
(ustx (get ustx swap)))
(asserts! (is-eq (contract-of ft) (get ft swap)) ERR_INVALID_FUNGIBLE_TOKEN)
(asserts! (is-eq (contract-of fees) (get fees swap)) ERR_INVALID_FEES_TRAIT)
(asserts! (is-eq tx-sender (get stx-sender swap)) ERR_NOT_STX_SENDER)
(asserts! (get open swap) ERR_ALREADY_DONE)
(asserts! (map-set swaps id (merge swap {open: false})) ERR_NATIVE_FAILURE)
(try! (contract-call? fees release-fees ustx))
(print
{
type: "cancel",
swap_type: "STX-FT",
contract_address: THIS-CONTRACT,
swap-id: id,
creator: tx-sender,
counterparty: (get ft-sender swap),
open: false,
fees: (contract-of fees),
in_contract: "STX",
in_amount: ustx,
in_decimals: u6,
out_contract: (contract-of ft),
out-amount: (get amount swap),
out-decimals: (unwrap! (contract-call? ft get-decimals) ERR_FT_FAILURE),
}
)
(match (as-contract (stx-transfer-to
ustx (get stx-sender swap)
0x72657665727420636174616d6172616e2073776170))
success (ok success)
error (err (* error u100)))))
;; any user can submit a tx that contains the swap
(define-public (submit-swap
(id uint)
(ft <fungible-token>)
(fees <fees-trait>))
(let ((swap (unwrap! (map-get? swaps id) ERR_INVALID_ID))
(ustx (get ustx swap))
(stx-receiver (default-to tx-sender (get ft-sender swap)))
(ft-amount (get amount swap)))
(asserts! (get open swap) ERR_ALREADY_DONE)
(asserts! (is-eq (contract-of ft) (get ft swap)) ERR_INVALID_FUNGIBLE_TOKEN)
(asserts! (is-eq (contract-of fees) (get fees swap)) ERR_INVALID_FEES_TRAIT)
(asserts! (map-set swaps id (merge swap {open: false})) ERR_NATIVE_FAILURE)
(asserts! (is-eq tx-sender stx-receiver) ERR_INVALID_STX_RECEIVER) ;; assert out if the receiver is predetermined
(try! (contract-call? fees pay-fees ustx))
(print
{
type: "swap",
swap_type: "STX-FT",
contract_address: THIS-CONTRACT,
swap-id: id,
creator: (get stx-sender swap),
counterparty: tx-sender,
open: false,
fees: (contract-of fees),
in_contract: "STX",
in_amount: ustx,
in_decimals: u6,
out_contract: (contract-of ft),
out-amount: ft-amount,
out-decimals: (unwrap! (contract-call? ft get-decimals) ERR_FT_FAILURE),
}
)
(match (contract-call? ft transfer
ft-amount stx-receiver (get stx-sender swap)
(some 0x636174616d6172616e2073776170))
success-ft (begin
(asserts! success-ft ERR_NATIVE_FAILURE)
(match (as-contract (stx-transfer-to
(get ustx swap) stx-receiver
0x636174616d6172616e2073776170))
success-stx (ok success-stx)
error-stx (err (* error-stx u100))))
error-ft (err (* error-ft u1000)))))
(define-constant ERR_INVALID_ID (err u6))
(define-constant ERR_ALREADY_DONE (err u7))
(define-constant ERR_INVALID_FUNGIBLE_TOKEN (err u8))
(define-constant ERR_INVALID_STX_RECEIVER (err u9))
(define-constant ERR_INVALID_FEES (err u10))
(define-constant ERR_INVALID_FEES_TRAIT (err u11))
(define-constant ERR_NOT_STX_SENDER (err u12))
(define-constant ERR_FT_FAILURE (err u13))
(define-constant ERR_NATIVE_FAILURE (err u99))