import {
	APP_INITIALIZER,
	EnvironmentProviders,
	FactoryProvider,
	Injector,
	makeEnvironmentProviders,
} from '@angular/core';
import { AngularRenderer } from '@storybook/angular';
import { DecoratorFunction } from '@storybook/types';

type AngularStorybookDecorator<TArgs = unknown> = DecoratorFunction<
	AngularRenderer,
	TArgs
>;
type StoryFnAngularReturnType = ReturnType<AngularStorybookDecorator>;

function provideInjectorProp(
	story: StoryFnAngularReturnType
): EnvironmentProviders {
	function initializeStory(injector: Injector): () => void {
		return () => {
			story.props = {
				injector,
				...story.props,
			};
		};
	}

	const storyInitializer: FactoryProvider = {
		provide: APP_INITIALIZER,
		multi: true,
		useFactory: initializeStory,
		deps: [Injector],
	};

	return makeEnvironmentProviders([storyInitializer]);
}

/**
 * Add `injector` to passed props.
 * 
 * @see https://jgelin.medium.com/inject-angular-services-in-storybook-7-c26b7f5a41e5 by Jonathan Gelin
 */
export function withInjectorProp<TArgs = unknown>(): DecoratorFunction<
	AngularRenderer,
	TArgs
> {
	return storyFn => {
		const story = storyFn();

		story.applicationConfig ??= { providers: [] };

		story.applicationConfig.providers = [
			provideInjectorProp(story),
			...story.applicationConfig.providers,
		];

		return story;
	};
}