import { expect, test } from '@playwright/test';
import { PDFDocument } from 'pdf-lib';
import { TextOverlayError } from '../../src/lib/pdf-errors';
import type { OverlayPosition } from '../../src/lib/pdf-overlay';
import {
	MAX_FREE_TEXT_LENGTH,
	PAGINATION_FORMATS,
	buildPaginationLabel,
	normalizeFreeText,
	normalizeStartNumber,
	paginatePdf,
	type PaginationFormat,
	type PaginationOptions,
	type PaginationTextScope
} from '../../src/lib/pdf-pagination';
import { getPageTextValues } from '../e2e/helpers';

const labelOptions = (
	overrides: Partial<{
		startNumber: number;
		freeText: string;
		textScope: PaginationTextScope;
		format: PaginationFormat;
	}> = {}
) => ({
	startNumber: 1,
	freeText: '',
	textScope: 'all' as const,
	format: 'blatt' as const,
	...overrides
});

const paginationOptions = (overrides: Partial<PaginationOptions> = {}): PaginationOptions => ({
	startNumber: 1,
	freeText: '',
	textScope: 'all',
	format: 'blatt',
	position: 'bottom-center' as OverlayPosition,
	fontSize: 11,
	...overrides
});

/** Blank pages, so the stamped sheet number is the only text in the output. */
const createPdf = async (pageCount: number, size: [number, number] = [420, 594]) => {
	const document = await PDFDocument.create();

	for (let index = 0; index < pageCount; index += 1) document.addPage(size);

	return new Uint8Array(await document.save());
};

test('every format is offered with a rendered example label', () => {
	expect(PAGINATION_FORMATS.map((format) => format.value)).toEqual([
		'blatt',
		'seite',
		's',
		'nummer'
	]);
	expect(PAGINATION_FORMATS.map((format) => format.label)).toEqual([
		'Bl. 1',
		'Seite 1',
		'S. 1',
		'1'
	]);
});

test('label combines the free text with the ascending sheet number', () => {
	expect(buildPaginationLabel(0, labelOptions({ startNumber: 26 }))).toBe('Bl. 26');
	expect(buildPaginationLabel(2, labelOptions({ startNumber: 26 }))).toBe('Bl. 28');
	expect(buildPaginationLabel(0, labelOptions({ freeText: '  123 Ja 60/26 ' }))).toBe(
		'123 Ja 60/26, Bl. 1'
	);
	expect(buildPaginationLabel(0, labelOptions({ format: 'seite', startNumber: 6 }))).toBe(
		'Seite 6'
	);
	expect(buildPaginationLabel(0, labelOptions({ format: 's', startNumber: 6 }))).toBe('S. 6');
	expect(buildPaginationLabel(0, labelOptions({ format: 'nummer', startNumber: 6 }))).toBe('6');
	// No leading zeros — a start number of 6 is not "06".
	expect(buildPaginationLabel(0, labelOptions({ startNumber: 6 }))).toBe('Bl. 6');
});

test('the free text is dropped on later pages for the first-page scope', () => {
	const options = labelOptions({ freeText: 'AZ 7/26', textScope: 'first', format: 's' });

	expect(buildPaginationLabel(0, options)).toBe('AZ 7/26, S. 1');
	expect(buildPaginationLabel(1, options)).toBe('S. 2');
});

test('start number and free text are normalised at the boundary', () => {
	expect(normalizeStartNumber(0)).toBe(1);
	expect(normalizeStartNumber(-5)).toBe(1);
	expect(normalizeStartNumber(2.6)).toBe(3);
	expect(normalizeStartNumber(Number.NaN)).toBe(1);
	expect(normalizeStartNumber(1_000_000)).toBe(99_999);

	expect(normalizeFreeText('  123 Ja 60/26  ')).toBe('123 Ja 60/26');
	expect(normalizeFreeText('x'.repeat(90))).toHaveLength(MAX_FREE_TEXT_LENGTH);
});

test('paginatePdf stamps each page exactly once', async () => {
	const output = await paginatePdf(
		await createPdf(3),
		paginationOptions({ startNumber: 26, freeText: '123 Ja 60/26' })
	);
	const document = await PDFDocument.load(output);

	expect(document.getPageCount()).toBe(3);
	expect(getPageTextValues(document, 0)).toEqual(['123 Ja 60/26, Bl. 26']);
	expect(getPageTextValues(document, 1)).toEqual(['123 Ja 60/26, Bl. 27']);
	expect(getPageTextValues(document, 2)).toEqual(['123 Ja 60/26, Bl. 28']);
});

test('paginatePdf honours the first-page-only scope', async () => {
	const output = await paginatePdf(
		await createPdf(2),
		paginationOptions({ freeText: 'AZ 7/26', textScope: 'first', format: 'nummer' })
	);
	const document = await PDFDocument.load(output);

	expect(getPageTextValues(document, 0)).toEqual(['AZ 7/26, 1']);
	expect(getPageTextValues(document, 1)).toEqual(['2']);
});

test('a label that cannot fit at the minimum font size fails loudly', async () => {
	await expect(
		paginatePdf(
			await createPdf(1, [120, 160]),
			paginationOptions({ freeText: 'x'.repeat(MAX_FREE_TEXT_LENGTH), fontSize: 18 })
		)
	).rejects.toBeInstanceOf(TextOverlayError);
});