import json
from datetime import datetime
from fastapi import APIRouter, HTTPException
from app.config import STATE_PATH

router = APIRouter()


@router.get("/status")
async def get_status():
    """Current monitor status: connected, CPS, last isotopes detected."""
    if not STATE_PATH.exists():
        raise HTTPException(status_code=503, detail="Monitor not started yet")

    try:
        with open(STATE_PATH) as f:
            state = json.load(f)
    except (json.JSONDecodeError, OSError):
        raise HTTPException(status_code=503, detail="Monitor state file corrupt")

    # Check staleness (> 5 minutes old)
    try:
        ts = datetime.fromisoformat(state["timestamp"])
        age = (datetime.now() - ts).total_seconds()
        state["stale"] = age > 300
        state["age_seconds"] = int(age)
    except (KeyError, ValueError):
        state["stale"] = True

    return {
        "connected": state.get("connected", False),
        "stale": state.get("stale", True),
        "age_seconds": state.get("age_seconds", 0),
        "timestamp": state.get("timestamp", ""),
        "cps": state.get("cps", 0),
        "cumulated_live_time_h": state.get("cumulated_live_time_h", 0),
        "total_counts": state.get("total_counts", 0),
        "background_subtracted": state.get("background_subtracted", False),
        "isotopes_detected": state.get("isotopes_detected", []),
    }