import { writeFileSync } from 'node:fs';

import { generate } from '@openvidu-dashboard/data-generator/generator';
import { queryContext, type QueryContext } from '@openvidu-dashboard/data-generator/context';
import { type Db, MongoClient } from 'mongodb';
import { afterAll, beforeAll, describe, expect, inject, it } from 'vitest';

import { Collection, EGRESS_IN_FLIGHT_STATUSES, type EgressDocument } from '@openvidu-dashboard/typings';

import { pageQuery } from '../../src/api/cursor.js';
import { rankedPipeline } from '../../src/api/ranked.js';
import { prefixRegex } from '../../src/api/search.js';
import { EGRESS_LIST_PROJECTION } from '../../src/egress/egress-mappers.js';
import { egressesListPlan } from '../../src/egress/egress-query.js';
import { egressesListQuery } from '../../src/egress/egress-schemas.js';
import { EgressService } from '../../src/egress/egress-service.js';
import { expectIdLookup, expectIndexBacked, expectIndexes, p95 } from '../support/query-plan.js';
import { expectWithinBudgets } from '../support/latency-budget.js';

/**
 * Every egress query explained, filter by filter, on a database generated by the data generator, plus
 * the p95 of the performance budget, which fails the suite when exceeded. EGRESS_PLAN_SCENARIO (S by default),
 * EGRESS_PLAN_DAYS (2 by default) and EGRESS_PLAN_REPORT (a file that also receives the report) work as in the rooms
 * suite.
 */

const mongoUri = inject('mongoUri');
const scenario = (process.env.EGRESS_PLAN_SCENARIO ?? 'S') as 'S' | 'M' | 'L';
const days = Number(process.env.EGRESS_PLAN_DAYS ?? '2');
const DATABASE = 'dashboard_test_egress_plan';
const LIMIT = 100;
const DAY = 86_400_000;
const GENERATION_TIMEOUT_MS = scenario === 'S' ? 600_000 : 3_600_000;

describe.skipIf(mongoUri === '')(`egress query plan at scenario ${scenario}`, () => {
	let client: MongoClient;
	let db: Db;
	let ctx: QueryContext;
	let service: EgressService;
	let sample: EgressDocument;
	/** An egress of a room and a prefix of its room name, so that the prefix always matches it. */
	let roomNameSample: { roomSid: string; prefix: string };
	const now = new Date();
	const report: string[] = [];

	const listParams = (query: Record<string, string>) =>
		egressesListQuery(() => now).parse({ from: ctx.range.from.toISOString(), limit: String(LIMIT), ...query });
	const egresses = () => db.collection<EgressDocument>(Collection.EGRESSES);
	const raw = () => db.collection(Collection.EGRESSES);
	/** The first page of a list request as the service reads it on the index of its plan. */
	const explainList = async (query: Record<string, string>, bound: number) => {
		const params = listParams(query);
		const plan = egressesListPlan(params);

		if (plan.kind === 'id') {
			throw new Error('expected a page or ranked plan');
		}

		const range = { from: params.from, to: params.to };
		const page = pageQuery('startedAt', params.order, undefined, range);

		if (plan.kind === 'ranked') {
			const match = { ...plan.filter, ...page.filter };
			const inRange = await raw().countDocuments(match);
			const request = {
				...params,
				match,
				rank: plan.rank,
				projection: EGRESS_LIST_PROJECTION,
				cursor: undefined,
				now
			};

			return expectIndexBacked(
				db,
				{
					collection: Collection.EGRESSES,
					pipeline: rankedPipeline(request, now),
					options: { hint: plan.hint }
				},
				{ maxDocsExamined: inRange }
			);
		}

		const direction: 1 | -1 = params.order === 'asc' ? 1 : -1;
		const sorted = plan.hint === 'startedAt_id' || plan.hint === 'roomNameLower_startedAt';

		return expectIndexBacked(
			db,
			raw()
				.find({ ...plan.filter, ...page.filter }, { projection: EGRESS_LIST_PROJECTION, hint: plan.hint })
				.sort(sorted ? page.sort : { startedAt: direction })
				.limit(LIMIT + 1),
			{ maxDocsExamined: bound }
		);
	};

	beforeAll(async () => {
		client = new MongoClient(mongoUri);
		db = client.db(DATABASE);
		await db.dropDatabase();
		await generate(db, {
			scenario,
			days,
			statsMode: 'participant',
			seed: 1,
			retentionDays: { events: 7, stats: 7, tracks: 7, entities: 90 },
			timeseries: true
		});
		ctx = await queryContext(db);
		service = new EgressService(db, { totalMaxRangeMs: 7 * DAY, now: () => now });

		const found = await egresses().findOne({ _id: ctx.samples.egressId });

		if (found === null) {
			throw new Error('the generated database has no sample egress');
		}

		sample = found;

		const ofRoom = await egresses().findOne({ roomNameLower: { $exists: true } });

		if (ofRoom?.roomSid === undefined || ofRoom.roomNameLower === undefined) {
			throw new Error('the generated database has no egress of a room');
		}

		roomNameSample = { roomSid: ofRoom.roomSid, prefix: ofRoom.roomNameLower.slice(0, -1) };
	}, GENERATION_TIMEOUT_MS);

	afterAll(async () => {
		if (report.length > 0) {
			const text = [`Egress p95 of 20 runs, scenario ${scenario}, ${String(days)} days`, ...report].join('\n');

			console.log(text);

			if (process.env.EGRESS_PLAN_REPORT !== undefined) {
				writeFileSync(process.env.EGRESS_PLAN_REPORT, `${text}\n`);
			}
		}

		await db.dropDatabase();
		await client.close();
	});

	it('status=all: startedAt_id without a sort, type residual', async () => {
		const inRange = await egresses().countDocuments({ startedAt: { $gte: ctx.range.from, $lt: now } });
		const all = await explainList({}, LIMIT + 1);

		expectIndexes(all, ['startedAt_id']);
		expect(all.planStages).not.toContain('SORT');
		expectIndexes(await explainList({ type: 'web' }, inRange), ['startedAt_id']);
	});

	it('status set: status_startedAt merged in startedAt order', async () => {
		const plan = await explainList({ status: EGRESS_IN_FLIGHT_STATUSES.join(',') }, LIMIT + 1);

		expectIndexes(plan, ['status_startedAt']);
		expect(plan.planStages).not.toContain('SORT');
		expectIndexes(await explainList({ status: 'failed,aborted', type: 'track' }, LIMIT * 60), ['status_startedAt']);
	});

	it('room: roomSid_startedAt, status and type residual', async () => {
		const ofRoom = await raw().countDocuments({ roomSid: sample.roomSid });

		expectIndexes(await explainList({ room: sample.roomSid ?? 'RM_none', status: 'complete' }, ofRoom), [
			'roomSid_startedAt'
		]);
	});

	it('room name prefix: roomNameLower_startedAt within the prefix, no room cap', async () => {
		const { roomSid, prefix } = roomNameSample;
		const inPrefix = await raw().countDocuments({ roomNameLower: prefixRegex(prefix) });
		const ofRoom = await raw().countDocuments({ roomSid });

		expect(inPrefix).toBeGreaterThan(0);
		expectIndexes(await explainList({ q: prefix }, inPrefix), ['roomNameLower_startedAt']);
		// With a room filter the room index serves the query and the prefix is a residual filter.
		expectIndexes(await explainList({ q: prefix, room: roomSid }, ofRoom), ['roomSid_startedAt']);
	});

	it.each(['endedAt', 'duration'])(
		'ranked by %s: the range index of the filters, at most the egresses in range',
		async (sort) => {
			expectIndexes(await explainList({ sort }, LIMIT), ['startedAt_id']);
			expectIndexes(await explainList({ sort, status: 'complete' }, LIMIT), ['status_startedAt']);
			expectIndexes(await explainList({ sort, room: sample.roomSid ?? 'RM_none' }, LIMIT), ['roomSid_startedAt']);
			expectIndexes(await explainList({ sort, q: roomNameSample.prefix }, LIMIT), ['roomNameLower_startedAt']);
		}
	);

	it('id, detail and summary: _id, status_startedAt and startedAt_id', async () => {
		expectIdLookup(
			await expectIndexBacked(db, egresses().find({ _id: sample._id }).limit(1), { maxDocsExamined: 1 })
		);

		const plan = egressesListPlan(listParams({ q: sample._id }));

		expect(plan).toEqual({ kind: 'id', filter: { _id: sample._id } });

		const active = await expectIndexBacked(
			db,
			egresses().find({ status: { $in: [...EGRESS_IN_FLIGHT_STATUSES] } }, { projection: { _id: 1 } }),
			{ maxDocsExamined: () => Number.MAX_SAFE_INTEGER }
		);

		expectIndexes(active, ['status_startedAt']);

		const figures = await expectIndexBacked(
			db,
			{
				collection: Collection.EGRESSES,
				pipeline: [
					{ $match: { startedAt: { $gte: new Date(now.getTime() - DAY), $lt: now } } },
					{ $count: 'n' }
				]
			},
			{ maxDocsExamined: () => Number.MAX_SAFE_INTEGER, collscanThreshold: 0 }
		);

		expect(figures.collscan).toBe(false);
	});

	it('reports the p95 of every budgeted query and fails above its budget', async () => {
		const prefix = (sample.roomName ?? 'room').slice(0, 3).toLowerCase();
		const rows: [string, number, () => Promise<unknown>][] = [
			['List, status all (100 rows)', 150, () => service.list(listParams({}))],
			['List, in flight', 150, () => service.list(listParams({ status: EGRESS_IN_FLIGHT_STATUSES.join(',') }))],
			['List, failed', 150, () => service.list(listParams({ status: 'failed' }))],
			['List, type=web', 300, () => service.list(listParams({ type: 'web' }))],
			['List, room', 150, () => service.list(listParams({ room: sample.roomSid ?? 'RM_none' }))],
			[`List, room name prefix "${prefix}"`, 200, () => service.list(listParams({ q: prefix }))],
			['List, ranked by endedAt', 200, () => service.list(listParams({ sort: 'endedAt' }))],
			['List, ranked by duration', 200, () => service.list(listParams({ sort: 'duration' }))],
			['Summary, exact (24 h)', 150, () => service.summary({ from: new Date(now.getTime() - DAY), to: now })],
			[
				'Summary, rollups (30 d)',
				100,
				() => service.summary({ from: new Date(now.getTime() - 30 * DAY), to: now })
			]
		];

		report.push('| Query | Budget | p95 |', '| --- | --- | --- |');

		const over: string[] = [];

		for (const [name, budget, run] of rows) {
			const measured = await p95(run);

			report.push(`| ${name} | ${String(budget)} ms | ${measured.toFixed(1)} ms |`);

			if (measured > budget) {
				over.push(`${name}: ${measured.toFixed(1)} ms > ${String(budget)} ms`);
			}
		}

		expectWithinBudgets(over);
	});
});