import { Signal } from '@angular/core';
import { toObservable, toSignal, ToSignalOptions } from '@angular/core/rxjs-interop';
import { debounceTime } from 'rxjs';

export function debouncedSignal<T>(
  source: Signal<T>,
  debounceDelay: number,
  options?: NoInfer<ToSignalOptions<T | undefined>> & {
    initialValue?: undefined;
    requireSync?: false;
  },
): Signal<T | undefined>;
export function debouncedSignal<T>(
  source: Signal<T>,
  debounceDelay: number,
  options: NoInfer<ToSignalOptions<T | null>> & {
    initialValue?: null;
    requireSync?: false;
  },
): Signal<T | null>;
export function debouncedSignal<T>(
  source: Signal<T>,
  debounceDelay: number,
  options: NoInfer<ToSignalOptions<T>> & {
    initialValue?: undefined;
    requireSync: true;
  },
): Signal<T>;
export function debouncedSignal<T, const U extends T>(
  source: Signal<T>,
  debounceDelay: number,
  options: NoInfer<ToSignalOptions<T | U>> & {
    initialValue: U;
    requireSync?: false;
  },
): Signal<T | U>;
/**
 * Creates a debounced signal from a source signal.
 * The debounced signal will wait for a specified delay after the last change before updating its value.
 *
 * @param source - The source signal to debounce
 * @param debounceDelay - The delay in milliseconds to wait after the last change
 * @param options - Optional configuration for the signal conversion
 *
 * @returns A new signal that updates after the specified delay
 *
 * @example
 * ```ts
 * const search = signal('');
 * const debouncedSearch = debouncedSignal(search, 300);
 * ```
 */
export function debouncedSignal<T, U = undefined>(
  source: Signal<T>,
  debounceDelay: number,
  options?: ToSignalOptions<T | U> & { initialValue?: U },
): Signal<T | U> {
  const sourceWithDebounce$ = toObservable(source).pipe(debounceTime(debounceDelay));

  return toSignal(
    sourceWithDebounce$,
    options as ToSignalOptions<T | undefined> & {
      initialValue?: undefined;
      requireSync?: false;
    },
  ) as Signal<T | U>;
}

const search = signal('');
const debouncedSearch = debouncedSignal(search, 300);