"""
Dashboard backend — WebSocket metrics server.

Reads live metrics from a shared JSON file (written by the live node)
and serves backtest results from disk. Streams everything to
connected dashboard clients via WebSocket.

Architecture:
  - /ws — WebSocket for real-time streaming
  - /backtests — list available backtest results
  - /backtest/{name} — serve specific backtest result
  - / — static HTML dashboard

Usage:
    python dashboard/server.py --port 9175
"""
import asyncio
import json
import os
import time
import threading
from pathlib import Path
from typing import Optional

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from fastapi.staticfiles import StaticFiles
from fastapi.responses import FileResponse, JSONResponse
import uvicorn

# ═══════════════════════════════════════════════════════════
# Constants
# ═══════════════════════════════════════════════════════════

METRICS_FILE = "/tmp/ftdt-metrics.json"
PAPER_METRICS_FILE = "/tmp/ftdt-paper-metrics.json"
BACKTEST_DIR = "/home/debian/ftdt-quant-lab/backtests/results"
STATIC_DIR = Path(__file__).parent / "static"

# Ensure backtest dir exists
os.makedirs(BACKTEST_DIR, exist_ok=True)

# ═══════════════════════════════════════════════════════════
# App
# ═══════════════════════════════════════════════════════════

app = FastAPI(title="FTDT Quant Lab Dashboard")
connected_clients: set[WebSocket] = set()
paper_clients: set[WebSocket] = set()
loop: Optional[asyncio.AbstractEventLoop] = None


# ═══════════════════════════════════════════════════════════
# Metrics reader
# ═══════════════════════════════════════════════════════════

def read_metrics() -> dict:
    """Read the shared metrics file written by the live node."""
    try:
        if os.path.exists(METRICS_FILE):
            with open(METRICS_FILE) as f:
                return json.load(f)
    except (json.JSONDecodeError, IOError):
        pass
    return _empty_metrics()


def _empty_metrics() -> dict:
    return {
        "timestamp": time.time(),
        "wallet": "0x...",
        "total_equity": 898.0,
        "total_pnl": 0.0,
        "total_pnl_pct": 0.0,
        "equity_history": [],
        "strategies": {},
        "trades": [],
        "status": "starting",
    }


def read_paper_metrics() -> dict:
    """Read paper trading metrics file."""
    try:
        if os.path.exists(PAPER_METRICS_FILE):
            with open(PAPER_METRICS_FILE) as f:
                return json.load(f)
    except (json.JSONDecodeError, IOError):
        pass
    return {"status": "waiting", "mode": "paper", "strategies": {}, "trades": [], "equity_history": [], "total_pnl": 0, "total_equity": 100000}


# ═══════════════════════════════════════════════════════════
# Background broadcaster
# ═══════════════════════════════════════════════════════════

async def broadcast_to_client(ws: WebSocket, payload: str):
    try:
        await ws.send_text(payload)
    except Exception:
        connected_clients.discard(ws)


def broadcast_loop():
    """Continuously read metrics and broadcast to all clients."""
    while True:
        time.sleep(1)
        data = read_metrics()
        payload = json.dumps(data, default=str)
        for ws in list(connected_clients):
            if loop:
                asyncio.run_coroutine_threadsafe(
                    broadcast_to_client(ws, payload), loop
                )

        # Also broadcast paper metrics
        paper_data = read_paper_metrics()
        paper_payload = json.dumps(paper_data, default=str)
        for ws in list(paper_clients):
            if loop:
                asyncio.run_coroutine_threadsafe(
                    broadcast_to_client(ws, paper_payload), loop
                )


# ═══════════════════════════════════════════════════════════
# WebSocket
# ═══════════════════════════════════════════════════════════

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    connected_clients.add(websocket)
    try:
        # Send initial state immediately
        data = read_metrics()
        await websocket.send_text(json.dumps(data, default=str))
        while True:
            await asyncio.sleep(30)
    except WebSocketDisconnect:
        connected_clients.discard(websocket)


@app.websocket("/ws/paper")
async def paper_websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    paper_clients.add(websocket)
    try:
        data = read_paper_metrics()
        await websocket.send_text(json.dumps(data, default=str))
        while True:
            await asyncio.sleep(30)
    except WebSocketDisconnect:
        paper_clients.discard(websocket)


# ═══════════════════════════════════════════════════════════
# Backtest endpoints
# ═══════════════════════════════════════════════════════════

@app.get("/api/backtests")
async def list_backtests():
    """List all saved backtest results."""
    results = []
    if os.path.isdir(BACKTEST_DIR):
        for fname in sorted(os.listdir(BACKTEST_DIR), reverse=True):
            if fname.endswith(".json"):
                fpath = os.path.join(BACKTEST_DIR, fname)
                try:
                    with open(fpath) as f:
                        data = json.load(f)
                    results.append({
                        "name": fname.replace(".json", ""),
                        "strategy": data.get("strategy", "unknown"),
                        "start": data.get("start_time"),
                        "end": data.get("end_time"),
                        "sharpe": data.get("sharpe", 0),
                        "sortino": data.get("sortino", 0),
                        "pnl_pct": data.get("pnl_pct", 0),
                        "max_dd": data.get("max_dd", 0),
                        "win_rate": data.get("win_rate", 0),
                        "total_trades": data.get("total_trades", 0),
                    })
                except (json.JSONDecodeError, IOError):
                    pass
    return JSONResponse(results)


@app.get("/api/backtest/{name}")
async def get_backtest(name: str):
    """Get full backtest result data."""
    fpath = os.path.join(BACKTEST_DIR, f"{name}.json")
    if os.path.exists(fpath):
        with open(fpath) as f:
            return JSONResponse(json.load(f))
    return JSONResponse({"error": "not found"}, status_code=404)


@app.get("/api/backtest/{name}/csv")
async def get_backtest_csv(name: str):
    """Download backtest trades as CSV."""
    from fastapi.responses import Response
    fpath = os.path.join(BACKTEST_DIR, f"{name}.json")
    if not os.path.exists(fpath):
        return JSONResponse({"error": "not found"}, status_code=404)
    with open(fpath) as f:
        data = json.load(f)
    trades = data.get("trades", [])
    # Build CSV with headers
    header = "time,side,size,price,pnl_gross,pnl_net,fee\n"
    rows = []
    for t in trades:
        rows.append(f"{t.get('time','')},{t.get('side','')},{t.get('size','')},{t.get('price','')},{t.get('pnl_gross',t.get('pnl',''))},{t.get('pnl_net',t.get('pnl',''))},{t.get('fee','0')}")
    csv_content = header + "\n".join(rows)
    return Response(
        content=csv_content,
        media_type="text/csv",
        headers={"Content-Disposition": f"attachment; filename={name}_trades.csv"}
    )


# ═══════════════════════════════════════════════════════════
# Static
# ═══════════════════════════════════════════════════════════

@app.get("/")
async def root():
    return FileResponse(STATIC_DIR / "index.html")


app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")


# ═══════════════════════════════════════════════════════════
# Main
# ═══════════════════════════════════════════════════════════

def main():
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("--port", type=int, default=9175)
    parser.add_argument("--host", default="0.0.0.0")
    args = parser.parse_args()

    global loop
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)

    # Start metrics broadcaster
    broadcaster = threading.Thread(target=broadcast_loop, daemon=True)
    broadcaster.start()

    print(f"FTDT Quant Lab Dashboard")
    print(f"  http://{args.host}:{args.port}")
    print(f"  WebSocket: ws://{args.host}:{args.port}/ws")
    print(f"  Backtests: /api/backtests")

    uvicorn.run(app, host=args.host, port=args.port, log_level="warning")


if __name__ == "__main__":
    main()