import random
from bots.base import BaseBot


class UpsBot(BaseBot):
    """UPS unit monitor."""

    interval = 60

    def __init__(self, site_id: str, ups_id: str) -> None:
        super().__init__()
        self.site_id = site_id
        self.ups_id = ups_id
        self._charge = 94.0 + random.uniform(-3, 3)
        self._on_battery = False

    def get_topic(self) -> str:
        return f"bms/{self.site_id}/power/{self.ups_id}"

    def set_scenario(self, name: str | None) -> None:
        super().set_scenario(name)
        if name in ("UPS_MAINS_FAILURE", "UPS_OVERLOAD"):
            self._on_battery = True
        elif name in (None, "RESET"):
            self._on_battery = False
            self._charge = 94.0

    def get_payload(self) -> dict:
        overload = (self._scenario == "UPS_OVERLOAD")

        if self._on_battery:
            # Overload drains battery ~4x faster — carrying full site load with no mains
            drain = random.uniform(3.0, 5.0) if overload else random.uniform(0.8, 1.5)
            self._charge = max(5.0, self._charge - drain)
            state = "overload" if overload else "on_battery"
            runtime = max(1, int((self._charge / 100) * (15 if overload else 60)))
        else:
            # Trickle charge back up when on mains
            self._charge = min(100.0, self._charge + random.uniform(0, 0.2))
            state = "online"
            runtime = int((self._charge / 100) * 60)

        if overload:
            load_pct = min(99.0, 88.0 + self._scenario_step * 1.2 + random.gauss(0, 1.5))
        else:
            load_pct = 62.0 + random.gauss(0, 2)

        return {
            "state":       state,
            "charge_pct":  round(self._charge, 1),
            "load_pct":    round(load_pct, 1),
            "runtime_min": runtime,
            "voltage":     round(229.5 + random.gauss(0, 0.5), 1),
        }