;; multiway-swap
;; Contract to facilitate a multiway NFT swap.
;; Each of the parties involved has to call confirm-and-escrow to escrow their dues.
;; Once all parties confirmed, finalize has to be called to redistribute escrowed items.
;; At any point before the swap is finalized it can be canceled by a party involved, 
;; regardles of whether they already called confirm-and-escrow or not.
${room_id}
${swap_id}

;; traders
${traders}
;; receivers
${receivers}

;; constants
(define-constant ERR_ESCROW_NOT_FILLED u401)
(define-constant ERR_SWAP_FINALIZED u402)
(define-constant ERR_RELEASING_ESCROW_FAILED u491)
(define-constant ERR_SWAP_CANCELED u499)

(define-constant ERR_IS_NOT_ADMIN u409)
(define-constant ERR_IS_NOT_TRADER u410)
(define-constant ERR_CALLER_ALREADY_ESCROWED u411)
(define-constant ERR_FAILED_TO_ESCROW_STX u412)
(define-constant ERR_FAILED_TO_ESCROW_NFT u413)

(define-constant SWAP_STATE_ACTIVE u100)
(define-constant SWAP_STATE_READY_TO_FINALIZE u101)
(define-constant SWAP_STATE_FINALIZED u102)
(define-constant SWAP_STATE_CANCELED u109)

(define-constant TRADER_STATE_ACTIVE u110)
(define-constant TRADER_STATE_CONFIRMED u111)
(define-constant TRADER_STATE_CANCELED u119)

(define-constant NUM_TRADERS u${num_traders})

(define-constant DEPLOYER tx-sender)

;; data maps and vars
(define-data-var swapState uint SWAP_STATE_ACTIVE)
(define-data-var confirmCount uint u0)

(define-map TraderState principal uint)

;; Set TraderState of each trader to TRADER_STATE_ACTIVE.
${traders_state}
;; private functions
(define-private (deposit-escrow) 
    (begin
${deposit_escrow}
        (map-set TraderState tx-sender TRADER_STATE_CONFIRMED)
        (unwrap-panic (update-swap-state))
        (ok true)
    )
)

(define-private (release-escrow) 
    (begin
${nfts_release_escrow}
${stx_release_escrow}
        (var-set swapState SWAP_STATE_FINALIZED)
        (ok true)
    )
)

(define-private (return-escrow) 
    (begin 
${traders_return_escrow}
        (map-set TraderState tx-sender TRADER_STATE_CANCELED)
        (var-set swapState SWAP_STATE_CANCELED)
        (ok true)
    )
)

(define-private (update-swap-state) 
    (let 
        ((cfCount (+ (var-get confirmCount) u1)))

        (var-set confirmCount cfCount)
        (if 
            (is-eq cfCount NUM_TRADERS)
            (var-set swapState SWAP_STATE_READY_TO_FINALIZE)
            true
        )
        (ok true)
    )
)

;; public functions
(define-read-only (get-swap-state) 
  (ok (var-get swapState))
)

(define-read-only (get-trader-state (trader principal)) 
  (unwrap! (map-get? TraderState trader) ERR_IS_NOT_TRADER)
)

(define-public (confirm-and-escrow) 
    (let 
        ((trState (unwrap! (map-get? TraderState tx-sender) (err ERR_IS_NOT_TRADER))))

        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_FINALIZED)) (err ERR_SWAP_FINALIZED))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_CANCELED)) (err ERR_SWAP_CANCELED))
        (asserts! (not (is-eq trState TRADER_STATE_CONFIRMED)) (err ERR_CALLER_ALREADY_ESCROWED))
        (try! (deposit-escrow))
        (ok true)
    )
)

(define-public (cancel) 
    (begin
        (unwrap! (map-get? TraderState tx-sender) (err ERR_IS_NOT_TRADER))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_FINALIZED)) (err ERR_SWAP_FINALIZED))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_CANCELED)) (err ERR_SWAP_CANCELED))
        (unwrap! (return-escrow) (err ERR_RELEASING_ESCROW_FAILED))
        (ok true)
    )
)

(define-public (admin-cancel) 
    (begin
        (asserts! (is-eq tx-sender DEPLOYER) (err ERR_IS_NOT_ADMIN))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_FINALIZED)) (err ERR_SWAP_FINALIZED))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_CANCELED)) (err ERR_SWAP_CANCELED))
        (unwrap! (return-escrow) (err ERR_RELEASING_ESCROW_FAILED))
        (ok true)
    )
)

(define-public (finalize) 
    (begin
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_ACTIVE)) (err ERR_ESCROW_NOT_FILLED))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_FINALIZED)) (err ERR_SWAP_FINALIZED))
        (asserts! (not (is-eq (var-get swapState) SWAP_STATE_CANCELED)) (err ERR_SWAP_CANCELED))
        (unwrap! (release-escrow) (err ERR_RELEASING_ESCROW_FAILED))
        (ok true)
    )
)