import { Callback, CallbackId } from "./types";

export class CallbacksManager {
    protected currentCallbackId = 0;
    protected callbacks: { [index: number]: { source: Callback; callback: Callback } } = {};
    createLinkToCallback = (id: CallbackId) => {
        const callbackItem = this.callbacks[id];
        if (!callbackItem) {
            throw new Error("Not found callback with id " + id);
        }
        this.currentCallbackId++;
        this.callbacks[this.currentCallbackId] = { source: callbackItem.callback, callback: callbackItem.callback };
        return this.currentCallbackId;
    };
    addCallback = (callback: Callback): [number, (value: any) => any] => {
        this.currentCallbackId++;
        const realCallback = ((callbackId: CallbackId) => (value: any) => {
            if (!this.callbacks[callbackId]) {
                return;
            }
            return this.callbacks[callbackId].source(value);
        })(this.currentCallbackId);
        this.callbacks[this.currentCallbackId] = { source: callback, callback };
        return [this.currentCallbackId, realCallback];
    };
    changeCallback = (id: CallbackId, callback: Callback) => {
        if (!this.callbacks[id]) {
            throw new Error("Not found callback with id " + id);
        }
        this.callbacks[id].source = callback;
    };
    getCallback = (id: CallbackId) => {
        if (!this.callbacks[id]) {
            throw new Error("Not found callback with id " + id);
        }
        return this.callbacks[id].callback;
    };
    releaseCallback = (id: CallbackId) => {
        delete this.callbacks[id];
    };
}