fix: bugs-01

backend/app/rules/dedup_rules.py

@@ -1,32 +1,18 @@
 """Transaction deduplication rules.
 
-Determines whether two transaction records likely represent the same
-underlying financial event captured from different screenshots / pages.
+Only marks records as duplicate when there is strong deterministic evidence.
+Highly similar records (same amount/time/counterparty) are intentionally kept
+for manual review to avoid filtering out potential scam brushing transactions.
 """
-from datetime import timedelta
 
 from app.models.transaction import TransactionRecord
 
-TIME_WINDOW = timedelta(minutes=5)
-
 
 def is_duplicate_pair(a: TransactionRecord, b: TransactionRecord) -> bool:
-    # Rule 1: exact order_no match
+    # Rule 1: exact order_no match (strong deterministic signal).
     if a.order_no and b.order_no and a.order_no == b.order_no:
         return True
 
-    # Rule 2: same amount + close time + same account tail
-    if (
-        float(a.amount) == float(b.amount)
-        and a.trade_time
-        and b.trade_time
-        and abs(a.trade_time - b.trade_time) <= TIME_WINDOW
-    ):
-        if a.self_account_tail_no and b.self_account_tail_no:
-            if a.self_account_tail_no == b.self_account_tail_no:
-                return True
-        # same counterparty and close time is also strong signal
-        if a.counterparty_name and a.counterparty_name == b.counterparty_name:
-            return True
-
+    # Intentionally do NOT deduplicate by amount/time similarity.
+    # Those records should enter the review stage for human confirmation.
     return False