import uuid
from datetime import datetime, timezone
from fastapi import APIRouter, HTTPException
from pydantic import BaseModel

router = APIRouter()

# In-memory store (demo — resets on restart)
_windows: list[dict] = []


class WindowCreate(BaseModel):
    site_id:          str
    title:            str
    target:           str   # "all", a room_id like "hall-a", or a rack_id like "rack-A01"
    target_label:     str   # human-readable label
    start_dt:         str   # ISO 8601
    end_dt:           str   # ISO 8601
    suppress_alarms:  bool = True
    notes:            str = ""


def _window_status(w: dict) -> str:
    now = datetime.now(timezone.utc).isoformat()
    if w["end_dt"] < now:
        return "expired"
    if w["start_dt"] <= now:
        return "active"
    return "scheduled"


@router.get("")
async def list_windows(site_id: str = "sg-01"):
    return [
        {**w, "status": _window_status(w)}
        for w in _windows
        if w["site_id"] == site_id
    ]


@router.post("", status_code=201)
async def create_window(body: WindowCreate):
    window = {
        "id":              str(uuid.uuid4())[:8],
        "site_id":         body.site_id,
        "title":           body.title,
        "target":          body.target,
        "target_label":    body.target_label,
        "start_dt":        body.start_dt,
        "end_dt":          body.end_dt,
        "suppress_alarms": body.suppress_alarms,
        "notes":           body.notes,
        "created_at":      datetime.now(timezone.utc).isoformat(),
    }
    _windows.append(window)
    return {**window, "status": _window_status(window)}


@router.delete("/{window_id}", status_code=204)
async def delete_window(window_id: str):
    global _windows
    before = len(_windows)
    _windows = [w for w in _windows if w["id"] != window_id]
    if len(_windows) == before:
        raise HTTPException(status_code=404, detail="Window not found")


@router.get("/active")
async def active_windows(site_id: str = "sg-01"):
    """Returns only currently active windows — used by alarm page for suppression check."""
    now = datetime.now(timezone.utc).isoformat()
    return [
        w for w in _windows
        if w["site_id"] == site_id
        and w["start_dt"] <= now <= w["end_dt"]
        and w["suppress_alarms"]
    ]