Initial commit: Gold Trading Simulator with AI-powered analysis

backend/app/api/trading.py

@@ -0,0 +1,133 @@
+from fastapi import APIRouter, HTTPException
+from typing import Dict
+from datetime import datetime, timezone
+
+from app.services.risk import validate_order
+
+router = APIRouter(prefix="/trading", tags=["Trading"])
+
+
+# In-memory simulation state (for MVP - will use DB in future)
+simulation_state = {
+    "cash": 100000.0,
+    "initial_capital": 100000.0,
+    "position": None,
+    "trades": [],
+    "equity_history": [],  # list of {time: epoch_sec, equity: float}
+}
+
+
+def _compute_equity_at_price(price: float) -> float:
+    pos = simulation_state.get("position")
+    qty = pos["quantity"] if pos else 0.0
+    return float(simulation_state.get("cash", 0.0) + qty * price)
+
+
+@router.post("/execute")
+async def execute_trade(trade: Dict):
+    """
+    Execute a trade in the simulation.
+
+    - Validates simple risk rules (position cap, anti-stacking)
+    - Updates cash/position
+    - Records trade with timestamp
+    - Appends equity snapshot after execution
+    """
+    try:
+        action = trade.get("action")
+        quantity = float(trade.get("quantity")) if trade.get("quantity") is not None else None
+        price = float(trade.get("price")) if trade.get("price") is not None else None
+
+        if not all([action, quantity is not None, price is not None]):
+            raise HTTPException(status_code=400, detail="Missing required fields")
+
+        # Risk validation prior to execution
+        try:
+            validate_order(simulation_state, action, quantity, price)
+        except ValueError as ve:
+            raise HTTPException(status_code=400, detail=str(ve))
+
+        total = quantity * price
+
+        if action == "BUY":
+            if total > simulation_state["cash"]:
+                raise HTTPException(status_code=400, detail="Insufficient funds")
+
+            simulation_state["cash"] -= total
+
+            if simulation_state["position"] is None:
+                simulation_state["position"] = {
+                    "symbol": "XAU/USD",
+                    "quantity": quantity,
+                    "avg_price": price,
+                }
+            else:
+                # Update average price for additional buy
+                pos = simulation_state["position"]
+                new_qty = pos["quantity"] + quantity
+                new_avg = (
+                    pos["avg_price"] * pos["quantity"] + price * quantity
+                ) / new_qty
+                pos["quantity"] = new_qty
+                pos["avg_price"] = new_avg
+
+        elif action == "SELL":
+            if (
+                simulation_state["position"] is None
+                or quantity > simulation_state["position"]["quantity"]
+            ):
+                raise HTTPException(status_code=400, detail="Insufficient position")
+
+            simulation_state["cash"] += total
+            pnl = (price - simulation_state["position"]["avg_price"]) * quantity
+
+            simulation_state["position"]["quantity"] -= quantity
+
+            if simulation_state["position"]["quantity"] == 0:
+                simulation_state["position"] = None
+
+            trade["pnl"] = pnl
+        else:
+            raise HTTPException(status_code=400, detail="Unsupported action")
+
+        now_ts = int(datetime.now(timezone.utc).timestamp())
+        trade["id"] = len(simulation_state["trades"]) + 1
+        trade["timestamp"] = now_ts
+        simulation_state["trades"].append(trade)
+
+        # Append equity snapshot post trade using trade price
+        equity = _compute_equity_at_price(price)
+        simulation_state["equity_history"].append({"time": now_ts, "equity": equity})
+
+        return trade
+
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.get("/portfolio")
+async def get_portfolio():
+    """Get current portfolio state"""
+    return simulation_state
+
+
+@router.post("/reset")
+async def reset_simulation():
+    """Reset simulation to initial state"""
+    global simulation_state
+    simulation_state = {
+        "cash": 100000.0,
+        "initial_capital": 100000.0,
+        "position": None,
+        "trades": [],
+        "equity_history": [],
+    }
+    return {"message": "Simulation reset successfully"}
+
+
+@router.get("/history")
+async def get_trade_history():
+    """Get trade history"""
+    return simulation_state["trades"]