fix: replace datetime.UTC with timezone.utc for Python 3.12+ compatibility

apps/exchange/exchange_api.py

@@ -3,7 +3,7 @@
 FastAPI backend for the AITBC Trade Exchange
 """
 
-from datetime import datetime, UTC, timedelta
+from datetime import datetime, timezone, timedelta
 from typing import List, Optional
 from fastapi import FastAPI, Depends, HTTPException, status, Header
 from fastapi.middleware.cors import CORSMiddleware
@@ -123,7 +123,7 @@ def create_mock_trades(db: Session):
     import random
     
     # Create mock trades over the last hour
-    now = datetime.now(datetime.UTC)
+    now = datetime.now(timezone.utc)
     trades = []
     
     for i in range(20):
@@ -278,7 +278,7 @@ def try_match_order(order: Order, db: Session):
             amount=trade_amount,
             price=match.price,
             total=trade_total,
-            trade_hash=f"trade_{datetime.now(datetime.UTC).timestamp()}"
+            trade_hash=f"trade_{datetime.now(timezone.utc).timestamp()}"
         )
         
         db.add(trade)
@@ -344,7 +344,7 @@ def logout_user(token: str = Header(..., alias="Authorization")):
 @app.get("/api/health")
 def health_check():
     """Health check endpoint"""
-    return {"status": "ok", "timestamp": datetime.now(datetime.UTC)}
+    return {"status": "ok", "timestamp": datetime.now(timezone.utc)}
 
 if __name__ == "__main__":
     import uvicorn

apps/exchange/models.py

@@ -22,7 +22,7 @@ class User(Base):
     password_hash = Column(String(255), nullable=False)
     bitcoin_address = Column(String(100), unique=True, nullable=False)
     aitbc_address = Column(String(100), unique=True, nullable=False)
-    created_at = Column(DateTime, default=datetime.now(datetime.UTC))
+    created_at = Column(DateTime, default=datetime.now(timezone.utc))
     is_active = Column(Boolean, default=True)
     
     # Relationships
@@ -46,8 +46,8 @@ class Order(Base):
     filled = Column(Float, default=0.0)  # Amount filled
     remaining = Column(Float, nullable=False)  # Amount remaining to fill
     status = Column(String(20), default='OPEN')  # OPEN, PARTIALLY_FILLED, FILLED, CANCELLED
-    created_at = Column(DateTime, default=datetime.now(datetime.UTC))
-    updated_at = Column(DateTime, default=datetime.now(datetime.UTC), onupdate=datetime.now(datetime.UTC))
+    created_at = Column(DateTime, default=datetime.now(timezone.utc))
+    updated_at = Column(DateTime, default=datetime.now(timezone.utc), onupdate=datetime.now(timezone.utc))
     
     # Relationships
     user = relationship("User", back_populates="orders")
@@ -74,7 +74,7 @@ class Trade(Base):
     price = Column(Float, nullable=False)  # Trade price in BTC
     total = Column(Float, nullable=False)  # Total value in BTC
     trade_hash = Column(String(100), unique=True, nullable=False)  # Blockchain transaction hash
-    created_at = Column(DateTime, default=datetime.now(datetime.UTC))
+    created_at = Column(DateTime, default=datetime.now(timezone.utc))
     
     # Relationships
     buyer = relationship("User", back_populates="trades", foreign_keys=[buyer_id])
@@ -100,7 +100,7 @@ class Balance(Base):
     aitbc_balance = Column(Float, default=0.0)
     btc_locked = Column(Float, default=0.0)  # Locked in open orders
     aitbc_locked = Column(Float, default=0.0)  # Locked in open orders
-    updated_at = Column(DateTime, default=datetime.now(datetime.UTC), onupdate=datetime.now(datetime.UTC))
+    updated_at = Column(DateTime, default=datetime.now(timezone.utc), onupdate=datetime.now(timezone.utc))
     
     # Relationship
     user = relationship("User")

apps/exchange/real_exchange_integration.py

@@ -8,7 +8,7 @@ import asyncio
 import ccxt
 import json
 import time
-from datetime import datetime, UTC, timedelta
+from datetime import datetime, timezone, timedelta
 from typing import Dict, List, Optional, Any, Tuple
 from dataclasses import dataclass
 from enum import Enum
@@ -105,7 +105,7 @@ class RealExchangeManager:
             self.health_status[exchange_name] = ExchangeHealth(
                 status=ExchangeStatus.CONNECTED,
                 latency_ms=0.0,
-                last_check=datetime.now(datetime.UTC)
+                last_check=datetime.now(timezone.utc)
             )
             
             logger.info(f"✅ Connected to {exchange_name}")
@@ -116,7 +116,7 @@ class RealExchangeManager:
             self.health_status[exchange_name] = ExchangeHealth(
                 status=ExchangeStatus.ERROR,
                 latency_ms=0.0,
-                last_check=datetime.now(datetime.UTC),
+                last_check=datetime.now(timezone.utc),
                 error_message=str(e)
             )
             return False

apps/exchange/scripts/seed_market.py

@@ -2,7 +2,7 @@
 """Seed initial market price for the exchange"""
 
 import sqlite3
-from datetime import datetime, UTC
+from datetime import datetime, timezone
 from aitbc.constants import DATA_DIR
 
 def seed_initial_price():
@@ -27,7 +27,7 @@ def seed_initial_price():
         cursor.execute('''
             INSERT INTO trades (amount, price, total, created_at)
             VALUES (?, ?, ?, ?)
-        ''', (amount, price, total, datetime.now(datetime.UTC)))
+        ''', (amount, price, total, datetime.now(timezone.utc)))
     
     # Also create some initial orders for liquidity
     initial_orders = [

apps/exchange/simple_exchange_api.py

@@ -5,7 +5,7 @@ Simple FastAPI backend for the AITBC Trade Exchange (Python 3.13 compatible)
 
 import sqlite3
 import json
-from datetime import datetime, UTC, timedelta
+from datetime import datetime, timezone, timedelta
 from http.server import HTTPServer, BaseHTTPRequestHandler
 import urllib.parse
 import random

apps/exchange/simple_exchange_api_pg.py

@@ -7,7 +7,7 @@ import json
 import urllib.request
 import psycopg2
 from psycopg2.extras import RealDictCursor
-from datetime import datetime, UTC
+from datetime import datetime, timezone
 from decimal import Decimal
 import random
 
@@ -151,7 +151,7 @@ class ExchangeAPIHandler(BaseHTTPRequestHandler):
             self.send_json_response({
                 'status': 'ok',
                 'database': 'postgresql',
-                'timestamp': datetime.now(datetime.UTC).isoformat()
+                'timestamp': datetime.now(timezone.utc).isoformat()
             })
         except Exception as e:
             self.send_json_response({

apps/exchange/tests/test_edge_cases_exchange.py

@@ -7,7 +7,7 @@ from pathlib import Path
 
 
 from exchange_api import OrderCreate, OrderResponse, TradeResponse, OrderBookResponse
-from datetime import datetime, UTC
+from datetime import datetime, timezone
 
 
 @pytest.mark.unit
@@ -55,7 +55,7 @@ def test_order_response_zero_remaining():
         filled=100.0,
         remaining=0.0,
         status="FILLED",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     assert order.remaining == 0.0
     assert order.status == "FILLED"
@@ -73,7 +73,7 @@ def test_order_response_empty_status():
         filled=0.0,
         remaining=100.0,
         status="",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     assert order.status == ""
 
@@ -86,7 +86,7 @@ def test_trade_response_zero_amount():
         amount=0.0,
         price=0.00001,
         total=0.0,
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     assert trade.amount == 0.0
     assert trade.total == 0.0
@@ -103,7 +103,7 @@ def test_order_book_empty_buys():
 @pytest.mark.unit
 def test_order_book_empty_sells():
     """Test OrderBookResponse with empty sells"""
-    from datetime import datetime, UTC
+    from datetime import datetime, timezone
     buy_order = OrderResponse(
         id=1,
         order_type="BUY",
@@ -113,7 +113,7 @@ def test_order_book_empty_sells():
         filled=0.0,
         remaining=100.0,
         status="OPEN",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     orderbook = OrderBookResponse(buys=[buy_order], sells=[])
     assert len(orderbook.buys) == 1

apps/exchange/tests/test_unit_exchange.py

@@ -45,7 +45,7 @@ def test_order_create_model_sell():
 @pytest.mark.unit
 def test_order_response_model():
     """Test OrderResponse model"""
-    from datetime import datetime, UTC
+    from datetime import datetime, timezone
     order = OrderResponse(
         id=1,
         order_type="BUY",
@@ -55,7 +55,7 @@ def test_order_response_model():
         filled=0.0,
         remaining=100.0,
         status="OPEN",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     assert order.id == 1
     assert order.order_type == "BUY"
@@ -66,13 +66,13 @@ def test_order_response_model():
 @pytest.mark.unit
 def test_trade_response_model():
     """Test TradeResponse model"""
-    from datetime import datetime, UTC
+    from datetime import datetime, timezone
     trade = TradeResponse(
         id=1,
         amount=50.0,
         price=0.00001,
         total=0.0005,
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     assert trade.id == 1
     assert trade.amount == 50.0
@@ -82,7 +82,7 @@ def test_trade_response_model():
 @pytest.mark.unit
 def test_order_book_response_model():
     """Test OrderBookResponse model"""
-    from datetime import datetime, UTC
+    from datetime import datetime, timezone
     buy_order = OrderResponse(
         id=1,
         order_type="BUY",
@@ -92,7 +92,7 @@ def test_order_book_response_model():
         filled=0.0,
         remaining=100.0,
         status="OPEN",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     sell_order = OrderResponse(
         id=2,
@@ -103,7 +103,7 @@ def test_order_book_response_model():
         filled=0.0,
         remaining=50.0,
         status="OPEN",
-        created_at=datetime.now(datetime.UTC)
+        created_at=datetime.now(timezone.utc)
     )
     orderbook = OrderBookResponse(buys=[buy_order], sells=[sell_order])
     assert len(orderbook.buys) == 1