import { describe, it, expect, vi, afterEach } from 'vitest';
import { cleanup, render } from 'vitest-browser-svelte';
import { page, userEvent } from 'vitest/browser';
import FileSwitcherStrip from './FileSwitcherStrip.svelte';
import type { FileEntry } from './FileSwitcherStrip.svelte';

afterEach(cleanup);

function makeFiles(n: number): FileEntry[] {
	return Array.from({ length: n }, (_, i) => ({
		id: `id-${i}`,
		file: new File([''], `file${i}.pdf`),
		title: `File ${i}`,
		status: 'idle' as const,
		previewUrl: ''
	}));
}

describe('FileSwitcherStrip', () => {
	it('renders N chips for N files', async () => {
		const files = makeFiles(4);
		render(FileSwitcherStrip, {
			files,
			activeId: files[0].id,
			onSelect: vi.fn(),
			onRemove: vi.fn()
		});
		const chips = page.getByRole('listitem');
		await expect.element(chips.nth(0)).toBeInTheDocument();
		await expect.element(chips.nth(3)).toBeInTheDocument();
	});

	it('active chip has aria-current="true"', async () => {
		const files = makeFiles(3);
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: files[1].id,
			onSelect: vi.fn(),
			onRemove: vi.fn()
		});
		const activeBtn = container.querySelector('[aria-current="true"]');
		expect(activeBtn).not.toBeNull();
		expect(activeBtn?.textContent).toContain('File 1');
	});

	it('clicking a chip fires onSelect with its id', async () => {
		const files = makeFiles(3);
		const onSelect = vi.fn();
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: files[0].id,
			onSelect,
			onRemove: vi.fn()
		});
		const chip = container.querySelector('[data-chip-id="id-2"]') as HTMLElement;
		expect(chip).not.toBeNull();
		chip.click();
		expect(onSelect).toHaveBeenCalledWith('id-2');
	});

	it('error chip has aria-label containing warning indicator', async () => {
		const files: FileEntry[] = [
			{
				id: 'e1',
				file: new File([''], 'bad.pdf'),
				title: 'Bad file',
				status: 'error',
				previewUrl: ''
			}
		];
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: 'e1',
			onSelect: vi.fn(),
			onRemove: vi.fn()
		});
		const errBtn = container.querySelector('[data-status="error"]');
		expect(errBtn).not.toBeNull();
	});

	it('error chip contains a screen-reader-only error label', async () => {
		const files: FileEntry[] = [
			{
				id: 'e1',
				file: new File([''], 'bad.pdf'),
				title: 'Bad file',
				status: 'error',
				previewUrl: ''
			}
		];
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: 'e1',
			onSelect: vi.fn(),
			onRemove: vi.fn()
		});
		const errBtn = container.querySelector('[data-status="error"]');
		const srOnly = errBtn?.querySelector('.sr-only');
		expect(srOnly).not.toBeNull();
	});

	it('focus moves to the previous chip after the middle chip is removed', async () => {
		const files = makeFiles(3); // id-0, id-1, id-2
		const onRemove = vi.fn();
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: files[1].id,
			onSelect: vi.fn(),
			onRemove
		});

		const removeBtn = container.querySelector('[data-remove-id="id-1"]') as HTMLButtonElement;
		expect(removeBtn).not.toBeNull();
		removeBtn.click();
		expect(onRemove).toHaveBeenCalledWith('id-1');

		// After removal, focus should be on the chip for id-0 (the previous chip)
		await vi.waitFor(
			() => {
				const prevChip = container.querySelector('[data-chip-id="id-0"]') as HTMLElement | null;
				expect(prevChip).not.toBeNull();
				expect(document.activeElement).toBe(prevChip);
			},
			{ timeout: 1000 }
		);
	});

	it('ArrowRight moves focus to next chip without leaving strip', async () => {
		const files = makeFiles(3);
		const { container } = render(FileSwitcherStrip, {
			files,
			activeId: files[0].id,
			onSelect: vi.fn(),
			onRemove: vi.fn()
		});
		const firstBtn = container.querySelectorAll('[data-chip-id]')[0] as HTMLElement;
		firstBtn.focus();
		await userEvent.keyboard('{ArrowRight}');
		const focused = document.activeElement;
		expect(focused).not.toBe(firstBtn);
		// The new focused element should still be inside the strip
		const strip = container.querySelector('[data-testid="file-switcher-strip"]');
		expect(strip?.contains(focused)).toBe(true);
	});
});