from __future__ import annotations

from collections import defaultdict
from collections.abc import Iterable
from dataclasses import dataclass


@dataclass(frozen=True)
class FeatureVector:
    sensor_id: str
    values: dict[str, float]
    label: str | None = None


class FeatureStore:
    def __init__(self) -> None:
        self._vectors: dict[str, list[FeatureVector]] = defaultdict(list)

    def add(self, vector: FeatureVector) -> None:
        self._vectors[vector.sensor_id].append(vector)

    def add_batch(self, vectors: Iterable[FeatureVector]) -> None:
        for vector in vectors:
            self.add(vector)

    def latest(self, sensor_id: str) -> FeatureVector | None:
        series = self._vectors.get(sensor_id)
        return series[-1] if series else None

    def all(self) -> list[FeatureVector]:
        return [vector for vectors in self._vectors.values() for vector in vectors]