;; ============================================================================
;; STACKS DEX - AMM Pool V2 (Compatible with ALEX token restrictions)
;; ============================================================================
;;
;; This version works with tokens that require tx-sender == sender or
;; contract-caller == sender for transfers (like ALEX token).
;;
;; The user must first transfer tokens TO the pool, then call swap.
;; The pool tracks pending deposits per user.
;; ============================================================================
(use-trait ft-trait .sip010-ft-trait.sip-010-trait)
;; Fee: 30 basis points = 0.30%
(define-constant FEE_BPS u30)
(define-constant BPS_DENOM u10000)
;; Error codes
(define-constant ERR_ZERO_INPUT (err u100))
(define-constant ERR_ZERO_RESERVES (err u101))
(define-constant ERR_DEADLINE_EXPIRED (err u102))
(define-constant ERR_SLIPPAGE_EXCEEDED (err u103))
(define-constant ERR_INSUFFICIENT_LIQUIDITY (err u104))
(define-constant ERR_TRANSFER_FAILED (err u105))
(define-constant ERR_ALREADY_INITIALIZED (err u200))
(define-constant ERR_NOT_INITIALIZED (err u201))
(define-constant ERR_NO_DEPOSIT (err u202))
;; State
(define-data-var fee-recipient (optional principal) none)
(define-data-var reserve-x uint u0)
(define-data-var reserve-y uint u0)
(define-data-var total-fees-collected uint u0)
;; Track deposits per user (for the 2-step swap process)
(define-map user-deposits
principal
uint
)
;; Read functions
(define-read-only (get-reserves)
{
x: (var-get reserve-x),
y: (var-get reserve-y),
}
)
(define-read-only (get-fee-info)
{
fee-bps: FEE_BPS,
denom: BPS_DENOM,
recipient: (var-get fee-recipient),
}
)
(define-read-only (get-total-fees)
(var-get total-fees-collected)
)
(define-read-only (get-user-deposit (user principal))
(default-to u0 (map-get? user-deposits user))
)
(define-read-only (quote-x-for-y (dx uint))
(let (
(rx (var-get reserve-x))
(ry (var-get reserve-y))
)
(asserts! (> dx u0) ERR_ZERO_INPUT)
(asserts! (and (> rx u0) (> ry u0)) ERR_ZERO_RESERVES)
(let (
(fee (/ (* dx FEE_BPS) BPS_DENOM))
(dx-to-pool (- dx fee))
(dy (/ (* ry dx-to-pool) (+ rx dx-to-pool)))
)
(asserts! (< dy ry) ERR_INSUFFICIENT_LIQUIDITY)
(ok dy)
)
)
)
(define-read-only (calculate-fee (dx uint))
(/ (* dx FEE_BPS) BPS_DENOM)
)
;; Step 1: User deposits tokens X directly to this contract
;; User calls: (contract-call? token-x transfer amount tx-sender pool-contract none)
;; Then calls this to register the deposit
(define-public (register-deposit (amount uint))
(begin
(asserts! (> amount u0) ERR_ZERO_INPUT)
(map-set user-deposits tx-sender (+ (get-user-deposit tx-sender) amount))
(ok amount)
)
)
;; Alternative: Single-step swap for tokens that DON'T have restrictions
;; The user calls this, and we transfer on their behalf
(define-public (swap-x-for-y
(token-x <ft-trait>)
(token-y <ft-trait>)
(dx uint)
(min-dy uint)
(recipient principal)
(deadline uint)
)
(let (
(rx (var-get reserve-x))
(ry (var-get reserve-y))
(sender tx-sender)
(fee-addr (unwrap! (var-get fee-recipient) ERR_NOT_INITIALIZED))
)
(asserts! (<= stacks-block-height deadline) ERR_DEADLINE_EXPIRED)
(asserts! (> dx u0) ERR_ZERO_INPUT)
(asserts! (and (> rx u0) (> ry u0)) ERR_ZERO_RESERVES)
(let (
(fee (/ (* dx FEE_BPS) BPS_DENOM))
(dx-to-pool (- dx fee))
(dy (/ (* ry dx-to-pool) (+ rx dx-to-pool)))
)
(asserts! (>= dy min-dy) ERR_SLIPPAGE_EXCEEDED)
(asserts! (< dy ry) ERR_INSUFFICIENT_LIQUIDITY)
;; Transfer fee to fee recipient (if fee > 0)
(if (> fee u0)
(unwrap! (contract-call? token-x transfer fee sender fee-addr none)
ERR_TRANSFER_FAILED
)
true
)
;; Transfer dx-to-pool from sender to this contract
(unwrap!
(contract-call? token-x transfer dx-to-pool sender
(as-contract tx-sender) none
)
ERR_TRANSFER_FAILED
)
;; Transfer dy from pool to recipient
(unwrap!
(as-contract (contract-call? token-y transfer dy tx-sender recipient none))
ERR_TRANSFER_FAILED
)
;; Update reserves
(var-set reserve-x (+ rx dx-to-pool))
(var-set reserve-y (- ry dy))
(var-set total-fees-collected (+ (var-get total-fees-collected) fee))
(ok {
dx: dx,
dy: dy,
fee: fee,
recipient: recipient,
})
)
)
)
;; Swap for Y using tokens X -> Y (Y for X direction)
(define-public (swap-y-for-x
(token-x <ft-trait>)
(token-y <ft-trait>)
(dy uint)
(min-dx uint)
(recipient principal)
(deadline uint)
)
(let (
(rx (var-get reserve-x))
(ry (var-get reserve-y))
(sender tx-sender)
(fee-addr (unwrap! (var-get fee-recipient) ERR_NOT_INITIALIZED))
)
(asserts! (<= stacks-block-height deadline) ERR_DEADLINE_EXPIRED)
(asserts! (> dy u0) ERR_ZERO_INPUT)
(asserts! (and (> rx u0) (> ry u0)) ERR_ZERO_RESERVES)
(let (
(fee (/ (* dy FEE_BPS) BPS_DENOM))
(dy-to-pool (- dy fee))
(dx (/ (* rx dy-to-pool) (+ ry dy-to-pool)))
)
(asserts! (>= dx min-dx) ERR_SLIPPAGE_EXCEEDED)
(asserts! (< dx rx) ERR_INSUFFICIENT_LIQUIDITY)
;; Transfer fee to fee recipient
(if (> fee u0)
(unwrap! (contract-call? token-y transfer fee sender fee-addr none)
ERR_TRANSFER_FAILED
)
true
)
;; Transfer dy-to-pool from sender to pool
(unwrap!
(contract-call? token-y transfer dy-to-pool sender
(as-contract tx-sender) none
)
ERR_TRANSFER_FAILED
)
;; Transfer dx from pool to recipient
(unwrap!
(as-contract (contract-call? token-x transfer dx tx-sender recipient none))
ERR_TRANSFER_FAILED
)
;; Update reserves
(var-set reserve-x (- rx dx))
(var-set reserve-y (+ ry dy-to-pool))
(var-set total-fees-collected (+ (var-get total-fees-collected) fee))
(ok {
dy: dy,
dx: dx,
fee: fee,
recipient: recipient,
})
)
)
)
;; Initialize pool with liquidity
(define-public (initialize-pool
(token-x <ft-trait>)
(token-y <ft-trait>)
(amount-x uint)
(amount-y uint)
)
(begin
(asserts! (and (is-eq (var-get reserve-x) u0) (is-eq (var-get reserve-y) u0))
ERR_ALREADY_INITIALIZED
)
(var-set fee-recipient (some tx-sender))
(unwrap!
(contract-call? token-x transfer amount-x tx-sender (as-contract tx-sender)
none
)
ERR_TRANSFER_FAILED
)
(unwrap!
(contract-call? token-y transfer amount-y tx-sender (as-contract tx-sender)
none
)
ERR_TRANSFER_FAILED
)
(var-set reserve-x amount-x)
(var-set reserve-y amount-y)
(ok {
x: amount-x,
y: amount-y,
fee-recipient: tx-sender,
})
)
)
(define-read-only (get-contract-info)
{
name: "dex-pool-v2",
version: "2.0.0",
fee-bps: FEE_BPS,
fee-recipient: (var-get fee-recipient),
reserve-x: (var-get reserve-x),
reserve-y: (var-get reserve-y),
total-fees: (var-get total-fees-collected),
}
)