flashloan-handler

;; title: strategy-flash-loans
;; version: 1.0.0
;; summary: Flash loan execution engine
;; description: Execute atomic flash loan strategies - Clarity 4

;; Constants
(define-constant CONTRACT-OWNER tx-sender)
(define-constant ERR-UNAUTHORIZED (err u2600))
(define-constant ERR-INVALID-AMOUNT (err u2601))
(define-constant ERR-LOAN-NOT-REPAID (err u2602))
(define-constant ERR-STRATEGY-PAUSED (err u2603))

;; Flash loan fee (basis points)
(define-constant FLASH-LOAN-FEE u9)  ;; 0.09%

;; Data Variables
(define-data-var strategy-paused bool false)
(define-data-var total-flash-loans uint u0)
(define-data-var total-fees-earned uint u0)
(define-data-var liquidity-pool uint u0)
(define-data-var next-loan-id uint u1)

;; Data Maps - Using stacks-block-time for Clarity 4
(define-map flash-loan-history uint {
  borrower: principal,
  amount: uint,
  fee: uint,
  executed-at: uint,  ;; Clarity 4: Unix timestamp
  repaid: bool,
  profit: uint
})

;; Public Functions

(define-public (execute-flash-loan (amount uint))
  (let (
    (loan-id (var-get next-loan-id))
    (fee (/ (* amount FLASH-LOAN-FEE) u10000))
    (total-repay (+ amount fee))
  )
    (asserts! (not (var-get strategy-paused)) ERR-STRATEGY-PAUSED)
    (asserts! (> amount u0) ERR-INVALID-AMOUNT)
    (asserts! (<= amount (var-get liquidity-pool)) ERR-INVALID-AMOUNT)

    ;; Execute flash loan logic here
    ;; Borrower must repay within same transaction

    (map-set flash-loan-history loan-id {
      borrower: tx-sender,
      amount: amount,
      fee: fee,
      executed-at: stacks-block-time,
      repaid: true,
      profit: u0
    })

    (var-set next-loan-id (+ loan-id u1))
    (var-set total-flash-loans (+ (var-get total-flash-loans) u1))
    (var-set total-fees-earned (+ (var-get total-fees-earned) fee))

    (print {
      event: "flash-loan-executed",
      loan-id: loan-id,
      amount: amount,
      fee: fee,
      timestamp: stacks-block-time
    })

    (ok loan-id)
  )
)

(define-public (add-liquidity (amount uint))
  (begin
    (asserts! (> amount u0) ERR-INVALID-AMOUNT)
    (try! (stx-transfer? amount tx-sender tx-sender))
    (var-set liquidity-pool (+ (var-get liquidity-pool) amount))
    (ok true)
  )
)

(define-public (pause-strategy)
  (begin
    (asserts! (is-eq tx-sender CONTRACT-OWNER) ERR-UNAUTHORIZED)
    (var-set strategy-paused true)
    (ok true)
  )
)

;; Read-Only Functions

(define-read-only (get-loan-history (loan-id uint))
  (map-get? flash-loan-history loan-id)
)

(define-read-only (get-liquidity-pool)
  (var-get liquidity-pool)
)

(define-read-only (get-total-fees)
  (var-get total-fees-earned)
)