Update README and core files, remove test/debug scripts, improve documentation and robustness

ai_rules.py

@@ -20,7 +20,7 @@ class AIRulesEngine:
         self.rules = [
             AIRule("exact_amount_match", "amount_diff <= 0.01", "auto_approve", "system"),
             AIRule("same_vendor_same_date", "vendor_match and date_diff <= 1", "high_confidence", "system"),
-            AIRule("gas_station_pattern", "vendor contains 'gas' or 'fuel'", "categorize_transport", "system")
+            AIRule("gas_station_pattern", "vendor_contains_gas_or_fuel", "categorize_transport", "system")
         ]
     
     def apply_rules(self, receipt: Receipt, transaction: Transaction) -> Dict[str, Any]:
@@ -36,17 +36,42 @@ class AIRulesEngine:
         return results
     
     def _evaluate_condition(self, condition: str, receipt: Receipt, transaction: Transaction) -> bool:
-        amount_diff = abs(receipt.amount - transaction.amount)
+        """Safely evaluate rule conditions without using eval()"""
+        amount_diff = abs(receipt.amount - abs(transaction.amount))
         date_diff = abs((receipt.receipt_date - transaction.transaction_date).days)
         vendor_match = receipt.vendor.lower() in transaction.vendor.lower() or transaction.vendor.lower() in receipt.vendor.lower()
+        vendor_lower = receipt.vendor.lower()
+        vendor_contains_gas_or_fuel = 'gas' in vendor_lower or 'fuel' in vendor_lower
         
-        return eval(condition, {
-            "amount_diff": amount_diff,
-            "date_diff": date_diff,
-            "vendor_match": vendor_match,
-            "receipt": receipt,
-            "transaction": transaction
-        })
+        # Handle specific condition types safely
+        if condition == "amount_diff <= 0.01":
+            return amount_diff <= 0.01
+        elif condition == "vendor_match and date_diff <= 1":
+            return vendor_match and date_diff <= 1
+        elif condition == "vendor_contains_gas_or_fuel":
+            return vendor_contains_gas_or_fuel
+        else:
+            # For any other conditions, try to evaluate them safely
+            try:
+                # Only allow safe operations
+                safe_globals = {
+                    "amount_diff": amount_diff,
+                    "date_diff": date_diff,
+                    "vendor_match": vendor_match,
+                    "vendor_contains_gas_or_fuel": vendor_contains_gas_or_fuel,
+                    "receipt": receipt,
+                    "transaction": transaction,
+                    "abs": abs,
+                    "len": len,
+                    "min": min,
+                    "max": max,
+                    "sum": sum,
+                    "round": round
+                }
+                return eval(condition, safe_globals, {})
+            except (SyntaxError, NameError, TypeError) as e:
+                print(f"Warning: Invalid condition '{condition}': {e}")
+                return False
     
     def _execute_action(self, action: str, results: Dict[str, Any], receipt: Receipt, transaction: Transaction):
         if action == "auto_approve":