import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { cleanup, render } from 'vitest-browser-svelte';
import { page } from 'vitest/browser';
import PersonMentionEditorHost from './PersonMentionEditor.test-host.svelte';
import type { components } from '$lib/generated/api';

type Person = components['schemas']['Person'];
type PersonMention = components['schemas']['PersonMention'];

// Editor's internal search debounce is 200ms — drive it via fake timers
// so tests are deterministic and fast (Tester #5506 §1).
const DEBOUNCE_MS = 200;

async function flushDebounce() {
	await vi.advanceTimersByTimeAsync(DEBOUNCE_MS);
	// Let the awaited fetch resolve and the resulting state assignments flush.
	await vi.runAllTimersAsync();
}

async function tick() {
	await vi.advanceTimersByTimeAsync(0);
}

const AUGUSTE: Person = {
	id: 'p-aug',
	firstName: 'Auguste',
	lastName: 'Raddatz',
	displayName: 'Auguste Raddatz',
	birthYear: 1882,
	deathYear: 1944
} as unknown as Person;

const ANNA: Person = {
	id: 'p-anna',
	firstName: 'Anna',
	lastName: 'Schmidt',
	displayName: 'Anna Schmidt',
	birthYear: 1860
} as unknown as Person;

function mockFetchWithPersons(persons: Person[] = [AUGUSTE, ANNA]) {
	const fetchMock = vi
		.fn()
		.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue(persons) });
	vi.stubGlobal('fetch', fetchMock);
	return fetchMock;
}

function mockFetchEmpty() {
	const fetchMock = vi.fn().mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([]) });
	vi.stubGlobal('fetch', fetchMock);
	return fetchMock;
}

function getTextarea(): HTMLTextAreaElement {
	return document.querySelector('textarea')!;
}

function clickOption(personId: string) {
	const opt = document.querySelector(
		`[role="option"][data-test-person-id="${personId}"]`
	) as HTMLElement;
	opt.dispatchEvent(new MouseEvent('mousedown', { bubbles: true, cancelable: true }));
}

type Snapshot = { value: string; mentionedPersons: PersonMention[] };

function renderHost(initial: { value?: string; mentionedPersons?: PersonMention[] } = {}) {
	let snapshot: Snapshot = {
		value: initial.value ?? '',
		mentionedPersons: initial.mentionedPersons ?? []
	};
	render(PersonMentionEditorHost, {
		initialValue: initial.value ?? '',
		initialMentions: initial.mentionedPersons ?? [],
		onChange: (snap: Snapshot) => {
			snapshot = snap;
		}
	});
	return {
		get snapshot() {
			return snapshot;
		}
	};
}

beforeEach(() => {
	vi.useFakeTimers({ shouldAdvanceTime: true });
});

afterEach(() => {
	cleanup();
	vi.unstubAllGlobals();
	vi.useRealTimers();
});

// ─── Rendering ────────────────────────────────────────────────────────────────

describe('PersonMentionEditor — rendering', () => {
	it('renders the textarea with placeholder', async () => {
		render(PersonMentionEditorHost, {
			initialValue: '',
			initialMentions: [],
			placeholder: 'Transkription…',
			onChange: () => {}
		});
		await expect.element(page.getByPlaceholder('Transkription…')).toBeInTheDocument();
	});

	it('reflects bound initial value', async () => {
		render(PersonMentionEditorHost, {
			initialValue: 'Hallo Welt',
			initialMentions: [],
			onChange: () => {}
		});
		await expect.element(page.getByRole('textbox')).toHaveValue('Hallo Welt');
	});
});

// ─── Typeahead opens on @ ─────────────────────────────────────────────────────

describe('PersonMentionEditor — typeahead', () => {
	it('opens the popup when typing @ + query and shows results', async () => {
		mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));

		await flushDebounce();

		await expect.element(page.getByText('Auguste Raddatz')).toBeInTheDocument();
	});

	it('hits /api/persons?q= with the typed query', async () => {
		const fetchMock = mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));

		await flushDebounce();

		expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('/api/persons?q=Aug'));
	});

	it('shows life dates next to the name in the dropdown', async () => {
		mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		await expect.element(page.getByText('* 1882 – † 1944')).toBeInTheDocument();
	});

	it('shows empty state when no persons match', async () => {
		mockFetchEmpty();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@xyz';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		await expect.element(page.getByText('Keine Personen gefunden')).toBeInTheDocument();
	});

	it('keeps the popup open when the query has a trailing space (multi-word names)', async () => {
		mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Auguste ';
		ta.selectionStart = 9;
		ta.selectionEnd = 9;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		await expect.element(page.getByText('Auguste Raddatz')).toBeInTheDocument();
	});
});

// ─── Selection writes text + sidecar ─────────────────────────────────────────

describe('PersonMentionEditor — selecting a person', () => {
	it('inserts @DisplayName followed by a trailing space into the textarea', async () => {
		mockFetchWithPersons();
		const host = renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		clickOption('p-aug');
		await tick();

		expect(host.snapshot.value).toBe('@Auguste Raddatz ');
	});

	it('pushes {personId, displayName} into the bound mentionedPersons array', async () => {
		mockFetchWithPersons();
		const host = renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		clickOption('p-aug');
		await tick();

		expect(host.snapshot.mentionedPersons).toEqual([
			{ personId: 'p-aug', displayName: 'Auguste Raddatz' }
		]);
	});

	it('does not duplicate the sidecar entry when the same person is selected twice', async () => {
		mockFetchWithPersons();
		const host = renderHost({
			value: '@Auguste Raddatz ',
			mentionedPersons: [{ personId: 'p-aug', displayName: 'Auguste Raddatz' }]
		});

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Auguste Raddatz @Aug';
		ta.selectionStart = ta.value.length;
		ta.selectionEnd = ta.value.length;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		clickOption('p-aug');
		await tick();

		expect(host.snapshot.mentionedPersons).toHaveLength(1);
	});
});

// ─── Keyboard navigation (B11b) ──────────────────────────────────────────────

describe('PersonMentionEditor — keyboard navigation (B11b)', () => {
	it('ArrowDown / ArrowUp cycle the highlighted result', async () => {
		mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@A';
		ta.selectionStart = 2;
		ta.selectionEnd = 2;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		const optAuguste = document.querySelector(
			'[role="option"][data-test-person-id="p-aug"]'
		) as HTMLElement;
		const optAnna = document.querySelector(
			'[role="option"][data-test-person-id="p-anna"]'
		) as HTMLElement;

		expect(optAuguste.getAttribute('aria-selected')).toBe('true');
		expect(optAnna.getAttribute('aria-selected')).toBe('false');

		ta.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
		await tick();

		expect(optAuguste.getAttribute('aria-selected')).toBe('false');
		expect(optAnna.getAttribute('aria-selected')).toBe('true');

		ta.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowUp', bubbles: true }));
		await tick();

		expect(optAuguste.getAttribute('aria-selected')).toBe('true');
		expect(optAnna.getAttribute('aria-selected')).toBe('false');
	});

	it('Enter selects the currently highlighted result', async () => {
		mockFetchWithPersons();
		const host = renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@A';
		ta.selectionStart = 2;
		ta.selectionEnd = 2;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		ta.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
		await tick();
		ta.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
		await tick();

		expect(host.snapshot.mentionedPersons).toEqual([
			{ personId: 'p-anna', displayName: 'Anna Schmidt' }
		]);
	});

	it('Escape closes the popup without inserting anything', async () => {
		mockFetchWithPersons();
		const host = renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		ta.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
		await tick();

		await expect.element(page.getByText('Auguste Raddatz')).not.toBeInTheDocument();
		expect(host.snapshot.value).toBe('@Aug');
		expect(host.snapshot.mentionedPersons).toEqual([]);
	});
});

// ─── Touch target (WCAG 2.2 AA) ──────────────────────────────────────────────

describe('PersonMentionEditor — touch target', () => {
	it('each result row has min-h-[44px] (WCAG 2.2 AA)', async () => {
		mockFetchWithPersons();
		renderHost();

		const ta = getTextarea();
		ta.focus();
		ta.value = '@Aug';
		ta.selectionStart = 4;
		ta.selectionEnd = 4;
		ta.dispatchEvent(new Event('input', { bubbles: true }));
		await flushDebounce();

		const option = document.querySelector('[role="option"]') as HTMLElement;
		expect(option).not.toBeNull();
		expect(option.className).toContain('min-h-[44px]');
	});
});