import assert from 'node:assert/strict';
import { afterEach, describe, it } from 'node:test';
import {
	assertReadMethod,
	splitLocal,
	UntisApiError,
	UntisClient,
	type UntisClient as UntisClientType,
	type UntisTimetable,
} from '../src/core/untis.ts';
import { readTimetable } from '../src/mcp/tools/untis.ts';

const CONFIG = { server: 'school.webuntis.com', school: 'demo', user: 'fia24b-test', secret: 'JBSWY3DPEHPK3PXP' };

/** Master data in the shape the live instance returns it. */
const MASTER = {
	timeStamp: 1,
	subjects: [
		{ id: 35, name: 'IT-FIA', longName: 'Fachtheorie FIA' },
		{ id: 130, name: 'Eth', longName: 'Ethik' },
	],
	teachers: [
		{ id: 1, name: 'Ra', firstName: 'Kristin', lastName: 'Rammelt' },
		{ id: 2, name: 'Hy', firstName: 'Justus', lastName: 'Hoyme' },
	],
	rooms: [
		{ id: 325, name: '42', longName: 'Raum 42' },
		{ id: 1, name: '001', longName: 'GR - Praxis' },
	],
	klassen: [{ id: 2757, name: 'FIA24B', longName: 'Fachinformatiker' }],
	holidays: [
		{
			name: 'Weltkindertag',
			longName: 'Weltkindertag (20.09.2026)',
			startDate: '2026-09-20',
			endDate: '2026-09-20',
		},
	],
};

const USER_DATA = {
	userData: {
		displayName: 'Hamm Fabian',
		elemId: 19_031,
		elemType: 'STUDENT',
		schoolName: 'Andreas-Gordon-Schule',
		rights: ['CLASSREGISTER', 'W_OWN_ABSENCE'],
	},
	masterData: MASTER,
};

/** A regular lesson, a cancelled one and its replacement in the same slot. */
const PERIODS = [
	{
		id: 100,
		lessonId: 900,
		startDateTime: '2026-09-21T08:00Z',
		endDateTime: '2026-09-21T08:45Z',
		text: { lesson: '', substitution: '', info: 'Test Projektdoku', attachments: [] },
		elements: [
			{ type: 'CLASS', id: 2757, orgId: 2757 },
			{ type: 'TEACHER', id: 1, orgId: 1 },
			{ type: 'SUBJECT', id: 35, orgId: 35 },
			{ type: 'ROOM', id: 325, orgId: 325 },
		],
		is: ['REGULAR'],
		homeWorks: [
			{ id: 7, lessonId: 900, startDate: '2026-09-14', endDate: '2026-09-21', text: 'Plakat mitbringen', completed: false },
		],
		exam: null,
		isOnlinePeriod: false,
	},
	{
		id: 101,
		lessonId: 901,
		startDateTime: '2026-09-21T10:05Z',
		endDateTime: '2026-09-21T10:50Z',
		elements: [
			{ type: 'TEACHER', id: 1, orgId: 1 },
			{ type: 'SUBJECT', id: 35, orgId: 35 },
		],
		is: ['CANCELLED'],
	},
	{
		id: 102,
		lessonId: 902,
		startDateTime: '2026-09-21T10:05Z',
		endDateTime: '2026-09-21T10:50Z',
		text: { substitution: 'Unterricht vom 30.09.2026' },
		elements: [
			{ type: 'TEACHER', id: 2, orgId: 2 },
			{ type: 'SUBJECT', id: 130, orgId: 130 },
			{ type: 'ROOM', id: 325, orgId: 1 },
		],
		is: ['IRREGULAR'],
	},
];

const savedFetch = globalThis.fetch;
afterEach(() => {
	globalThis.fetch = savedFetch;
});

/** Captures every request and answers per method. */
function stub(answers: Record<string, unknown>): { calls: { method: string; url: string; body: any }[] } {
	const calls: { method: string; url: string; body: any }[] = [];
	globalThis.fetch = (async (url: string | URL, init?: RequestInit) => {
		const body = JSON.parse(String(init?.body));
		calls.push({ method: body.method, url: String(url), body });
		const answer = answers[body.method];
		if (answer === undefined) return Response.json({ error: { code: -32_601, message: 'Method not found' } });
		if (answer instanceof Error) return Response.json({ error: { code: Number(answer.message), message: 'nope' } });
		return Response.json({ result: answer });
	}) as typeof fetch;
	return { calls };
}

describe('UntisClient: request shape', () => {
	it('signs each request with a padded string code and the school in the query', async () => {
		const { calls } = stub({ getUserData2017: USER_DATA });
		await new UntisClient(CONFIG).identity();

		const [call] = calls;
		assert.ok(call);
		assert.match(call.url, /^https:\/\/school\.webuntis\.com\/WebUntis\/jsonrpc_intern\.do\?/);
		assert.match(call.url, /m=getUserData2017/);
		assert.match(call.url, /school=demo/);
		// Without a version parameter the endpoint answers with a Java NPE.
		assert.match(call.url, /v=i3\.2/);
		const auth = call.body.params[0].auth;
		assert.equal(auth.user, 'fia24b-test');
		assert.equal(typeof auth.otp, 'string');
		assert.match(auth.otp, /^\d{6}$/);
		assert.ok(Math.abs(auth.clientTime - Date.now()) < 5_000);
		// The key itself never travels.
		assert.ok(!JSON.stringify(call.body).includes(CONFIG.secret));
	});

	it('refuses any method outside the read-only allowlist', () => {
		assert.throws(() => assertReadMethod('submitAbsencesChecked2017'), /read-only allowlist/);
		assert.throws(() => assertReadMethod('createImmediateAbsence2017'), /read-only allowlist/);
		assert.doesNotThrow(() => assertReadMethod('getTimetable2017'));
	});

	it('names the two failures a person has to act on', async () => {
		for (const [code, flag] of [
			[-8504, 'isAuthFailure'],
			[-8524, 'isClockSkew'],
		] as const) {
			stub({ getUserData2017: new Error(String(code)) });
			const error = await new UntisClient(CONFIG).identity().then(
				() => undefined,
				(e: unknown) => e,
			);
			assert.ok(error instanceof UntisApiError, `code ${code}`);
			assert.equal(error.code, code);
			assert.equal(error[flag], true);
		}
	});

	it('caches the identity but not a failure', async () => {
		const failing = stub({ getUserData2017: new Error('-8504') });
		const client = new UntisClient(CONFIG);
		await client.identity().catch(() => undefined);
		await client.identity().catch(() => undefined);
		assert.equal(failing.calls.length, 2, 'a rejected key must be retried after it is fixed');

		const working = stub({ getUserData2017: USER_DATA });
		const cached = new UntisClient(CONFIG);
		const first = await cached.identity();
		const second = await cached.identity();
		assert.equal(working.calls.length, 1);
		assert.equal(first.displayName, 'Hamm Fabian');
		assert.deepEqual(second.rights, ['CLASSREGISTER', 'W_OWN_ABSENCE']);
	});
});

describe('UntisClient: timetable', () => {
	const load = async (): Promise<UntisTimetable> => {
		stub({ getUserData2017: USER_DATA, getTimetable2017: { timetable: { periods: PERIODS }, masterData: MASTER } });
		return new UntisClient(CONFIG).timetable('2026-09-19', '2026-09-21');
	};

	it('keeps the reported clock time, which is local despite the Z', async () => {
		const table = await load();
		const monday = table.days.find((day) => day.date === '2026-09-21');
		assert.ok(monday);
		// 08:00Z must stay 08:00: the school's first lesson starts at eight.
		assert.equal(monday.lessons[0]?.start, '08:00');
		assert.equal(monday.lessons[0]?.end, '08:45');
	});

	it('includes days without lessons, with the holiday that explains them', async () => {
		const table = await load();
		assert.deepEqual(
			table.days.map((day) => day.date),
			['2026-09-19', '2026-09-20', '2026-09-21'],
		);
		const sunday = table.days.find((day) => day.date === '2026-09-20');
		assert.equal(sunday?.lessons.length, 0);
		assert.equal(sunday?.holidays[0]?.name, 'Weltkindertag');
		assert.equal(table.days.find((day) => day.date === '2026-09-19')?.holidays.length, 0);
	});

	it('resolves subjects, teachers, rooms and classes to their names', async () => {
		const lesson = (await load()).days.at(-1)?.lessons[0];
		assert.deepEqual(lesson?.subjects, [{ name: 'IT-FIA', longName: 'Fachtheorie FIA' }]);
		assert.deepEqual(lesson?.teachers, [{ name: 'Ra', longName: 'Kristin Rammelt' }]);
		assert.deepEqual(lesson?.rooms, [{ name: '42', longName: 'Raum 42' }]);
		assert.deepEqual(lesson?.classes, [{ name: 'FIA24B', longName: 'Fachinformatiker' }]);
		assert.equal(lesson?.notes.info, 'Test Projektdoku');
		assert.equal(lesson?.homework[0]?.due, '2026-09-21');
		assert.equal(lesson?.periodId, 100);
	});

	it('marks a cancellation and its replacement, including what was replaced', async () => {
		const lessons = (await load()).days.at(-1)!.lessons;
		const cancelled = lessons.find((lesson) => lesson.periodId === 101);
		const replacement = lessons.find((lesson) => lesson.periodId === 102);
		assert.equal(cancelled?.cancelled, true);
		assert.equal(cancelled?.changed, false);
		assert.equal(replacement?.changed, true);
		assert.equal(replacement?.cancelled, false);
		assert.equal(replacement?.notes.substitution, 'Unterricht vom 30.09.2026');
		// The room carries an orgId of its own: the lesson is in 42 instead of 001,
		// and `replaced` is the room it moved out of.
		assert.deepEqual(replacement?.rooms, [{ name: '42', longName: 'Raum 42' }]);
		assert.deepEqual(replacement?.replaced.rooms, [{ name: '001', longName: 'GR - Praxis' }]);
	});

	it('sorts a day by clock time', async () => {
		const starts = (await load()).days.at(-1)!.lessons.map((lesson) => lesson.start);
		assert.deepEqual(starts, ['08:00', '10:05', '10:05']);
	});

	it('throws on a timestamp it cannot read rather than dropping the lesson', () => {
		assert.throws(() => splitLocal('21.09.2026 08:00'), /unexpected format/);
		assert.deepEqual(splitLocal('2026-09-21T08:00Z'), { date: '2026-09-21', time: '08:00' });
	});
});

describe('UntisClient: homework and lesson topics', () => {
	it('resolves a homework subject through its lesson', async () => {
		stub({
			getUserData2017: USER_DATA,
			getHomeWork2017: {
				homeWorks: [
					{
						id: 16_404,
						lessonId: 71_296,
						startDate: '2026-08-24',
						endDate: '2026-08-31',
						text: 'Material Plakat Kohlbergs Stufenmodell',
						remark: null,
						completed: false,
						attachments: [],
					},
				],
				lessonsById: { '71296': { id: 71_296, subjectId: 130 } },
			},
		});
		const [item] = await new UntisClient(CONFIG).homework('2026-08-01', '2026-09-30');
		assert.equal(item?.subject?.name, 'Eth');
		assert.equal(item?.due, '2026-08-31');
		assert.equal(item?.assigned, '2026-08-24');
		assert.equal(item?.completed, false);
	});

	it('reads what previous lessons covered, dropping the empty entries', async () => {
		stub({
			getUserData2017: USER_DATA,
			getLessonTopic2017: {
				previousTopics: [
					{ text: 'Projektplanung und Risikoanalyse', periodId: 5, startDateTime: '2026-09-02T11:45Z', endDateTime: '2026-09-02T12:30Z' },
					{ text: '   ', periodId: 6, startDateTime: '2026-09-01T11:45Z', endDateTime: '2026-09-01T12:30Z' },
				],
			},
		});
		const topics = await new UntisClient(CONFIG).lessonTopics(100);
		assert.equal(topics.length, 1);
		assert.deepEqual(topics[0], {
			text: 'Projektplanung und Risikoanalyse',
			periodId: 5,
			date: '2026-09-02',
			start: '11:45',
			end: '12:30',
		});
	});
});

describe('readTimetable', () => {
	/** Only the two methods the renderer uses, so the formatting is what is tested. */
	const fake = (days: UntisTimetable['days'], messages: { subject: string; text: string }[] = []) =>
		({
			timetable: async (from: string, to: string) => ({
				from,
				to,
				days: days.filter((day) => day.date >= from && day.date <= to),
			}),
			messagesOfDay: async () => messages,
		}) as unknown as UntisClientType;

	const lesson = (over: Partial<UntisTimetable['days'][number]['lessons'][number]> = {}) => ({
		periodId: 100,
		lessonId: 900,
		date: '2026-09-21',
		start: '08:00',
		end: '08:45',
		statuses: ['REGULAR'],
		cancelled: false,
		changed: false,
		subjects: [{ name: 'IT-FIA', longName: 'Fachtheorie FIA' }],
		teachers: [{ name: 'Ra', longName: 'Kristin Rammelt' }],
		rooms: [{ name: '42' }],
		classes: [],
		replaced: { subjects: [], teachers: [], rooms: [] },
		notes: {},
		homework: [],
		online: false,
		...over,
	});

	it('renders a day with its weekday, subject, room, teacher and period id', async () => {
		const out = await readTimetable(fake([{ date: '2026-09-21', lessons: [lesson()], holidays: [] }]), {
			from: '2026-09-21',
			to: '2026-09-21',
		});
		assert.match(out, /## Montag, 21\.09\.2026/);
		assert.match(out, /08:00–08:45 \*\*IT-FIA\*\* \(Fachtheorie FIA\) · Raum 42 · Ra \(Kristin Rammelt\)/);
		assert.match(out, /`100`/);
	});

	it('says Entfall, and names who a Vertretung stands in for', async () => {
		const lessons = [
			lesson({ periodId: 101, cancelled: true, statuses: ['CANCELLED'] }),
			lesson({
				periodId: 102,
				changed: true,
				statuses: ['IRREGULAR'],
				teachers: [{ name: 'Hy', longName: 'Justus Hoyme' }],
				notes: { substitution: 'Unterricht vom 30.09.2026' },
			}),
		];
		const out = await readTimetable(fake([{ date: '2026-09-21', lessons, holidays: [] }]), {
			from: '2026-09-21',
			to: '2026-09-21',
		});
		assert.match(out, /\*\*Entfall\*\*/);
		assert.match(out, /\*\*Vertretung\*\* \(statt Ra\)/);
		assert.match(out, /Vertretungstext: Unterricht vom 30\.09\.2026/);
	});

	it('explains an empty day and points at the next one with lessons', async () => {
		const out = await readTimetable(
			fake([
				{ date: '2026-09-17', lessons: [], holidays: [] },
				{ date: '2026-09-21', lessons: [lesson()], holidays: [] },
			]),
			{ from: '2026-09-17', to: '2026-09-17' },
		);
		assert.match(out, /No lessons\. Not a holiday either/);
		assert.match(out, /\*\*Next lessons:\*\* Montag, 21\.09\.2026 \(1 lesson\(s\)\)/);
	});

	it('names the holiday when there is one, instead of guessing', async () => {
		const out = await readTimetable(
			fake([
				{
					date: '2026-10-13',
					lessons: [],
					holidays: [{ name: 'Herbstferien', longName: 'Herbstferien (12.10.-23.10.)', start: '2026-10-12', end: '2026-10-23' }],
				},
			]),
			{ from: '2026-10-13', to: '2026-10-13' },
		);
		assert.match(out, /Herbstferien \(12\.10\.-23\.10\.\)/);
		assert.match(out, /_No lessons\._/);
		assert.doesNotMatch(out, /company phase/);
	});

	it('with changesOnly lists only changed days, and says so when none changed', async () => {
		const days = [
			{ date: '2026-09-21', lessons: [lesson()], holidays: [] },
			{ date: '2026-09-22', lessons: [lesson({ date: '2026-09-22', periodId: 103, cancelled: true })], holidays: [] },
		];
		const out = await readTimetable(fake(days), { from: '2026-09-21', to: '2026-09-22', changesOnly: true });
		assert.match(out, /Dienstag, 22\.09\.2026/);
		assert.doesNotMatch(out, /Montag, 21\.09\.2026/);

		const quiet = await readTimetable(fake([days[0]!]), { from: '2026-09-21', to: '2026-09-21', changesOnly: true });
		assert.match(quiet, /Nothing cancelled or changed/);
		// The next-lessons hint is about lessons, so it has no place here.
		assert.doesNotMatch(quiet, /Next lessons/);
	});

	it('appends the Nachrichten des Tages for a single day only', async () => {
		const day = [{ date: '2026-09-21', lessons: [lesson()], holidays: [] }];
		const messages = [{ subject: 'Hitzefrei', text: 'Unterrichtsschluss 12:30' }];
		const single = await readTimetable(fake(day, messages), { from: '2026-09-21', to: '2026-09-21' });
		assert.match(single, /Nachrichten des Tages/);
		assert.match(single, /Hitzefrei: Unterrichtsschluss 12:30/);

		const range = await readTimetable(fake(day, messages), { from: '2026-09-21', to: '2026-09-25' });
		assert.doesNotMatch(range, /Nachrichten des Tages/);
	});
});