Update time-auction.clar

contracts/time-auction.clar

@@ -23,6 +23,8 @@
 (define-constant ERR_ALREADY_SETTLED (err u6007))
 (define-constant ERR_RESERVE_NOT_MET (err u6008))
 (define-constant ERR_INVALID_DURATION (err u6009))
+(define-constant ERR_NO_BID_TO_WITHDRAW (err u6010))
+(define-constant ERR_NOT_HIGHEST_BIDDER (err u6011))
 
 ;; Minimum auction duration: 1 hour
 (define-constant MIN_DURATION u3600)
@@ -316,6 +318,71 @@
   )
 )
 
+;; Withdraw bid (only if not the highest bidder)
+(define-public (withdraw-non-winning-bid (auction-id uint))
+  (let
+    (
+      (auction (unwrap! (map-get? auctions { auction-id: auction-id }) ERR_AUCTION_NOT_FOUND))
+      (user tx-sender)
+    )
+    ;; Auction must still be active
+    (asserts! (is-auction-active auction-id) ERR_AUCTION_ENDED)
+
+    ;; Cannot withdraw if you're the highest bidder
+    (match (get highest-bidder auction)
+      highest-bidder (asserts! (not (is-eq user highest-bidder)) ERR_NOT_HIGHEST_BIDDER)
+      true
+    )
+
+    ;; Find and refund user's last bid
+    (let
+      (
+        (user-last-bid (find-user-last-bid auction-id user))
+      )
+      (asserts! (is-some user-last-bid) ERR_NO_BID_TO_WITHDRAW)
+      (let
+        (
+          (bid-amount (get amount user-last-bid))
+        )
+        (begin
+          ;; Refund the bid amount
+          (try! (stx-transfer? bid-amount tx-sender user))
+
+          ;; Update user stats
+          (update-user-stats-after-withdrawal user)
+
+          ;; Log event
+          (log-bid-withdrawn auction-id user bid-amount)
+
+          (ok true)
+        )
+      )
+    )
+  )
+)
+
+
+;; Check if user can withdraw their bid from an auction
+(define-read-only (can-withdraw-bid (auction-id uint) (user principal))
+  (match (map-get? auctions { auction-id: auction-id })
+    auction
+      (ok (and
+            (is-auction-active auction-id)
+            (not (is-eq user (default-to user (get highest-bidder auction))))
+            (is-some (find-user-last-bid auction-id user))
+          ))
+    false
+  )
+)
+
+;; Get user's last bid amount in an auction
+(define-read-only (get-user-last-bid (auction-id uint) (user principal))
+  (match (find-user-last-bid auction-id user)
+    bid (ok (get amount bid))
+    none (ok u0)
+  )
+)
+
 ;; Settle auction after it ends
 (define-public (settle-auction (auction-id uint))
   (let
@@ -414,3 +481,49 @@
     (ok true)
   )
 )
+
+(define-private (find-user-last-bid (auction-id uint) (user principal))
+  (let
+    (
+      (auction (unwrap! (map-get? auctions { auction-id: auction-id }) ERR_AUCTION_NOT_FOUND))
+      (bid-count (get bid-count auction))
+    )
+    (find-user-last-bid-helper auction-id user (- bid-count u1))
+  )
+)
+
+(define-private (find-user-last-bid-helper (auction-id uint) (user principal) (index uint))
+  (if (>= index u0)
+    (match (map-get? bid-history { auction-id: auction-id, bid-index: index })
+      bid (if (is-eq (get bidder bid) user)
+            (some bid)
+            (find-user-last-bid-helper auction-id user (- index u1)))
+      (find-user-last-bid-helper auction-id user (- index u1))
+    )
+    none
+  )
+)
+
+;; Helper to update user bid stats when withdrawing
+(define-private (update-user-stats-after-withdrawal (user principal))
+  (let
+    (
+      (user-stat (default-to { active-bids: u0, total-bids: u0, wins: u0 }
+                            (map-get? user-bids { user: user })))
+    )
+    (if (> (get active-bids user-stat) u0)
+      (map-set user-bids
+        { user: user }
+        (merge user-stat {
+          active-bids: (- (get active-bids user-stat) u1)
+        })
+      )
+      true
+    )
+  )
+)
+
+;; Add logging event for bid withdrawal
+(define-private (log-bid-withdrawn (auction-id uint) (bidder principal) (amount uint))
+  (print { event: "bid-withdrawn", auction-id: auction-id, bidder: bidder, amount: amount, timestamp: stacks-block-time })
+)