import { EventType } from "../types";
import { IElementState, ElementId, IElementVar } from "../types/element";
import { EventsManager } from "../EventsManager";
import { CallbacksManager } from "../CallbacksManager";

export function useStateHook(
    eventsManager: EventsManager,
    callbacksManager: CallbacksManager,
    elementId: ElementId,
    state: IElementState,
    defaultValue: any,
): [any, (value: any) => void] {
    const currentVarNumber = state.tickState.currentVarNumber;
    state.tickState.currentVarNumber++;
    if (state.isFirstTick) {
        const [setter, callback] = eventsManager.createEvent(elementId, EventType.ChangeVar, {
            varNumber: currentVarNumber,
        });
        const createdVar: IElementVar = {
            value: defaultValue,
            setter,
        };
        state.vars.push(createdVar);
        return [createdVar.value, callback];
    }
    const varItem = state.vars[currentVarNumber];
    if (!varItem) {
        throw new Error("Expected var with number " + currentVarNumber);
    }
    return [varItem.value, callbacksManager.getCallback(varItem.setter)];
}