import { combineSubscriptions, type Subscription } from "@akala/core";
import type { Composer } from "../template.js";
import { DataContext } from "./context.js";
import { AttributeComposer } from "./shared.js";
import { fromEvent } from "../common.js";

export interface EventPlugin
{
    beforeEventRegistration?<T>(item: Element, options: T, handler: (...args: unknown[]) => unknown): void | Subscription;
    afterEventRegistration?<T>(item: Element, options: T, handler: (...args: unknown[]) => unknown, subscription: Subscription): Subscription | void;
}

export class EventComposer<T extends Partial<Disposable>> extends AttributeComposer<T> implements Composer<T>
{
    public static readonly plugins: Record<PropertyKey, EventPlugin> = {};

    getContext(item: HTMLElement, options?: T)
    {
        return DataContext.find(item);
    }

    constructor()
    {
        super('on')
    }

    optionName = 'controller';

    applyInternal<const TKey extends PropertyKey>(item: HTMLElement, options: T, event: TKey, handler: (...args: unknown[]) => unknown): Subscription | void
    {
        const ev = fromEvent(item, event as keyof HTMLElementEventMap);

        const preSub = EventComposer.plugins[event]?.beforeEventRegistration?.(item, options, handler);

        const result = ev.addListener(handler);

        const postSub = EventComposer.plugins[event]?.afterEventRegistration?.(item, options, handler, result)

        return combineSubscriptions(preSub, result, postSub);
    }
}