"""Owner-assigned drive slots, independent of USB addresses and motor commands."""
import json

LAYOUTS = {"1x1": ("left.1", "right.1"), "2x2": ("left.1", "left.2", "right.1", "right.2")}

def slot_label(layout, slot):
    side = "Левый" if slot.startswith("left.") else "Правый"
    return side + ((" передний" if slot.endswith(".1") else " задний") if layout == "2x2" else "")


class DriveProfile:
    def __init__(self, root, atomic):
        self.path, self.atomic = root / "drive-profile.json", atomic
        self.value = json.loads(self.path.read_text()) if self.path.exists() else {"layout": None, "revision": 0, "bindings": {}}

    def update(self, action, params, device):
        current = self.value
        if params["revision"] != current["revision"]:
            raise ValueError("Профиль привода изменился. Обновите карточку.")
        bindings = dict(current["bindings"])
        layout = current["layout"]
        if action == "vesc.drive.layout":
            layout = params["layout"]
            if set(bindings) - set(LAYOUTS[layout]):
                raise ValueError("Сначала снимите назначения задних моторов.")
        elif action == "vesc.drive.assign":
            layout, slot = params["layout"], params["slot"]
            if set(bindings) - set(LAYOUTS[layout]):
                raise ValueError("Сначала снимите назначения задних моторов.")
            if slot and slot in bindings and bindings[slot]["device_id"] != device.id:
                raise ValueError("Это место уже занято. Сначала снимите прежнее назначение.")
            bindings = {key: value for key, value in bindings.items() if value["device_id"] != device.id}
            if slot:
                bindings[slot] = {"device_id": device.id, "uuid": device.identity["uuid"]}
        else:
            bindings.pop(params["slot"], None)
        value = {"layout": layout, "revision": current["revision"] + 1, "bindings": bindings}
        self.atomic(self.path, value)
        self.value = value
        return value


def validate(action, params):
    keys = {"revision", "layout"} if action == "vesc.drive.layout" else ({"revision", "layout", "slot"} if action == "vesc.drive.assign" else {"revision", "slot"})
    if set(params) != keys or type(params["revision"]) is not int or params["revision"] < 0:
        raise ValueError("Invalid drive profile revision")
    if action == "vesc.drive.layout":
        if params["layout"] not in LAYOUTS:
            raise ValueError("Invalid drive layout")
    elif action == "vesc.drive.assign":
        if params["layout"] not in LAYOUTS or params["slot"] not in ("", *LAYOUTS[params["layout"]]):
            raise ValueError("Invalid drive layout or slot")
    elif params["slot"] not in LAYOUTS["2x2"]:
        raise ValueError("Invalid drive slot")