import { extract } from "../extract/extract.svelte.js";
/**
 * Function that takes a callback, and returns a debounced version of it.
 * When calling the debounced function, it will wait for the specified time
 * before calling the original callback. If the debounced function is called
 * again before the time has passed, the timer will be reset.
 *
 * You can await the debounced function to get the value when it is eventually
 * called.
 *
 * The second parameter is the time to wait before calling the original callback.
 * Alternatively, it can also be a getter function that returns the time to wait.
 *
 * @see {@link https://runed.dev/docs/utilities/use-debounce}
 *
 * @param callback The callback to call when the time has passed.
 * @param wait The length of time to wait in ms, defaults to 250.
 */
export function useDebounce(callback, wait) {
    let context = $state(null);
    const wait$ = $derived(extract(wait, 250));
    function debounced(...args) {
        if (context) {
            // Old context will be reused so callers awaiting the promise will get the
            // new value
            if (context.timeout) {
                clearTimeout(context.timeout);
            }
        }
        else {
            // No old context, create a new one
            let resolve;
            let reject;
            const promise = new Promise((res, rej) => {
                resolve = res;
                reject = rej;
            });
            context = {
                timeout: null,
                runner: null,
                promise,
                resolve: resolve,
                reject: reject,
            };
        }
        context.runner = async () => {
            // Grab the context and reset it
            // -> new debounced calls will create a new context
            if (!context)
                return;
            const ctx = context;
            context = null;
            try {
                ctx.resolve(await callback.apply(this, args));
            }
            catch (error) {
                ctx.reject(error);
            }
        };
        context.timeout = setTimeout(context.runner, wait$);
        return context.promise;
    }
    debounced.cancel = async () => {
        if (!context || context.timeout === null) {
            // Wait one event loop to see if something triggered the debounced function
            await new Promise((resolve) => setTimeout(resolve, 0));
            if (!context || context.timeout === null)
                return;
        }
        clearTimeout(context.timeout);
        context.reject("Cancelled");
        context = null;
    };
    debounced.runScheduledNow = async () => {
        if (!context || !context.timeout) {
            // Wait one event loop to see if something triggered the debounced function
            await new Promise((resolve) => setTimeout(resolve, 0));
            if (!context || !context.timeout)
                return;
        }
        clearTimeout(context.timeout);
        context.timeout = null;
        await context.runner?.();
    };
    Object.defineProperty(debounced, "pending", {
        enumerable: true,
        get() {
            return !!context?.timeout;
        },
    });
    return debounced;
}