// Shared browser-test mock body for the SvelteKit `$app/forms` virtual module.
//
// Imported into a sync vi.mock factory via the $mocks alias:
//   import * as formsMock from '$mocks/$app/forms';
//   vi.mock('$app/forms', () => ({ ...formsMock }));
//
// `enhance` intercepts the form's submit event, invokes the component's
// SubmitFunction, and — when that returns a post-submit callback — calls it
// with the configurable `_formResult`. Tests drive the success/failure branch
// with `setFormResult({ type: 'failure' })`. The embedded `beforeEach` resets
// the result before every test, so isolation is structural, not per-spec.
// See ADR-012.

import { beforeEach } from 'vitest';

export type FormEnhanceResult = { type: string; data?: Record<string, unknown> };

let _formResult: FormEnhanceResult = { type: 'success' };

export function setFormResult(result: FormEnhanceResult): void {
	_formResult = result;
}

export function enhance(
	node: HTMLFormElement,
	submit?: (opts: {
		formData: FormData;
	}) => (opts: { result: FormEnhanceResult; update: () => Promise<void> }) => Promise<void>
): { destroy: () => void } {
	const handler = async (e: Event) => {
		e.preventDefault();
		const callback = submit?.({ formData: new FormData(node) } as never);
		if (typeof callback === 'function') {
			await callback({ result: _formResult, update: async () => {} });
		}
	};
	node.addEventListener('submit', handler);
	return { destroy: () => node.removeEventListener('submit', handler) };
}

beforeEach(() => {
	_formResult = { type: 'success' };
});