import { EventEmitter } from 'node:events';
import http from 'node:http';
import https from 'node:https';
import type { IncomingMessage } from 'node:http';
import type { AddressInfo } from 'node:net';
import type { Duplex } from 'node:stream';
import { afterEach, describe, expect, it, vi } from 'vitest';

import { WebSocketServer } from '../src/server';

// RFC 6455 §1.3 example.
const RFC_KEY = 'dGhlIHNhbXBsZSBub25jZQ==';
const RFC_SWITCHING =
    'HTTP/1.1 101 Switching Protocols\r\n' +
    'Upgrade: websocket\r\n' +
    'Connection: Upgrade\r\n' +
    'Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=\r\n' +
    '\r\n';

const METHOD_NOT_ALLOWED =
    'HTTP/1.1 405 Method Not Allowed\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 18\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Method not allowed';

const BAD_UPGRADE_HEADER =
    'HTTP/1.1 400 Bad Request\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 32\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Upgrade header must be websocket';

const BAD_CONNECTION_HEADER =
    'HTTP/1.1 400 Bad Request\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 40\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Connection header must contain "upgrade"';

const BAD_KEY =
    'HTTP/1.1 400 Bad Request\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 25\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Invalid Sec-WebSocket-Key';

const VERSION_REQUIRED =
    'HTTP/1.1 426 Upgrade Required\r\n' +
    'Sec-WebSocket-Version: 13\r\n' +
    'Connection: close\r\n' +
    '\r\n';

const UNAUTHORIZED =
    'HTTP/1.1 401 Unauthorized\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 12\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Unauthorized';

const BAD_PATH =
    'HTTP/1.1 400 Bad Request\r\n' +
    'Connection: close\r\n' +
    'Content-Length: 22\r\n' +
    'Content-Type: text/plain\r\n' +
    '\r\n' +
    'Bad path for WebSocket';

const SHUTDOWN_CLOSE_FRAME = Buffer.from([
    0x88, 0x16, 0x03, 0xe9, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x68, 0x75, 0x74, 0x74,
    0x69, 0x6e, 0x67, 0x20, 0x64, 0x6f, 0x77, 0x6e,
]);

class MockSocket extends EventEmitter {
    readonly writes: Buffer[] = [];
    destroyed = false;
    ended = false;
    timeout: number | undefined;
    noDelay: boolean | undefined;
    encrypted: boolean | undefined;
    private readonly failWrite: boolean;
    private readonly failDestroy: boolean;

    constructor(opts?: { encrypted?: boolean; throwOnWrite?: boolean; throwOnDestroy?: boolean }) {
        super();
        this.encrypted = opts?.encrypted;
        this.failWrite = opts?.throwOnWrite === true;
        this.failDestroy = opts?.throwOnDestroy === true;
    }

    write(data: string | Buffer): boolean {
        if (this.failWrite) {
            throw new Error('write failed');
        }

        this.writes.push(typeof data === 'string' ? Buffer.from(data) : Buffer.from(data));
        return true;
    }

    get text(): string {
        return Buffer.concat(this.writes).toString('utf8');
    }

    setTimeout(ms: number): this {
        this.timeout = ms;
        return this;
    }

    setNoDelay(value: boolean): this {
        this.noDelay = value;
        return this;
    }

    end(data?: string | Buffer): this {
        if (data !== undefined) {
            this.write(data);
        }

        this.ended = true;
        this.emit('end');
        this.destroy();
        return this;
    }

    destroy(): this {
        if (this.failDestroy) {
            throw new Error('destroy failed');
        }

        this.destroyed = true;
        this.emit('close');
        return this;
    }
}

function asSocket(socket: MockSocket): Duplex {
    return socket as unknown as Duplex;
}

function upgradeRequest(
    overrides: {
        method?: string;
        url?: string;
        headers?: Record<string, string | string[] | undefined>;
    } = {},
): IncomingMessage {
    return {
        method: overrides.method ?? 'GET',
        url: 'url' in overrides ? overrides.url : '/',
        headers: {
            upgrade: 'websocket',
            connection: 'Upgrade',
            'sec-websocket-version': '13',
            'sec-websocket-key': RFC_KEY,
            ...overrides.headers,
        },
    } as IncomingMessage;
}

function listen(server: http.Server): Promise<number> {
    return new Promise((resolve, reject) => {
        const onError = (err: Error) => {
            server.off('listening', onListening);
            reject(err);
        };

        const onListening = () => {
            server.off('error', onError);
            resolve((server.address() as AddressInfo).port);
        };

        server.once('error', onError);
        server.listen(0, '127.0.0.1', onListening);
    });
}

function waitListening(wss: WebSocketServer): Promise<void> {
    return new Promise((resolve, reject) => {
        const onError = (err: Error) => {
            wss.off('listening', onListening);
            reject(err);
        };

        const onListening = () => {
            wss.off('error', onError);
            resolve();
        };

        wss.once('listening', onListening);
        wss.once('error', onError);
    });
}

function closeWss(wss: WebSocketServer): Promise<void> {
    return new Promise((resolve) => {
        wss.close(() => resolve());
    });
}

function closeHttp(server: http.Server): Promise<void> {
    return new Promise((resolve) => {
        server.close(() => resolve());
    });
}

function stubListenServer(address = { address: '127.0.0.1', family: 'IPv4', port: 8443 }) {
    const stub = {
        listen: vi.fn((..._args: unknown[]) => stub),
        on: vi.fn(),
        close: (cb?: (err?: Error) => void) => {
            cb?.();
        },
        address: () => address,
    };
    return stub;
}

const ownedServers: WebSocketServer[] = [];
const httpServers: http.Server[] = [];

afterEach(async () => {
    const pendingWss = ownedServers.splice(0);
    const pendingHttp = httpServers.splice(0);
    await Promise.all(pendingWss.map((wss) => closeWss(wss)));
    await Promise.all(pendingHttp.map((server) => closeHttp(server)));
    vi.restoreAllMocks();
});

describe('WebSocketServer constructor', () => {
    it('throws when neither port, server, nor noServer is provided', () => {
        expect(() => new WebSocketServer()).toThrowError(
            'WebSocketServer requires { port } or { server } or { noServer: true }',
        );
        expect(() => new WebSocketServer({})).toThrowError(
            'WebSocketServer requires { port } or { server } or { noServer: true }',
        );
    });

    it('stores options and skips listening in noServer mode', () => {
        const verifyClient = () => true;
        const wss = new WebSocketServer({
            noServer: true,
            path: '/ws',
            maxPayload: 4096,
            verifyClient,
            protocols: ['chat'],
            perMessageDeflate: true,
            backlog: 128,
            host: '127.0.0.1',
            port: 9,
        });
        ownedServers.push(wss);

        expect(wss.options).toEqual({
            port: 9,
            host: '127.0.0.1',
            server: undefined,
            noServer: true,
            path: '/ws',
            maxPayload: 4096,
            verifyClient,
            protocols: ['chat'],
            perMessageDeflate: true,
            backlog: 128,
            tls: undefined,
        });
        expect(wss.clients).toEqual(new Set());
        expect(wss.address()).toBeNull();
    });

    it('does not attach to a provided server when noServer is set', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ noServer: true, server });
        ownedServers.push(wss);
        expect(server.listenerCount('upgrade')).toBe(0);
    });

    it('copies listed TLS keys into options.tls and ignores non-TLS fields', () => {
        const wss = new WebSocketServer({
            noServer: true,
            cert: 'CERT',
            key: 'KEY',
            rejectUnauthorized: false,
            ca: undefined,
            host: '127.0.0.1',
        } as never);
        ownedServers.push(wss);
        expect(wss.options.tls).toEqual({
            cert: 'CERT',
            key: 'KEY',
            rejectUnauthorized: false,
        });
    });

    it('lets a tls object overwrite top-level TLS keys', () => {
        const wss = new WebSocketServer({
            noServer: true,
            cert: 'TOP',
            key: 'TOPKEY',
            tls: { cert: 'NESTED', passphrase: 'p' },
        });
        ownedServers.push(wss);
        expect(wss.options.tls).toEqual({
            cert: 'NESTED',
            key: 'TOPKEY',
            passphrase: 'p',
        });
    });

    it('leaves options.tls unset when no TLS material is present', () => {
        const wss = new WebSocketServer({ noServer: true, tls: {} });
        ownedServers.push(wss);
        expect(wss.options.tls).toBeUndefined();
    });

    it('attaches an upgrade listener to an existing server', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/ws' });
        ownedServers.push(wss);
        expect(wss.options.server).toBe(server);
        expect(server.listenerCount('upgrade')).toBe(1);
        expect(wss.address()).toBeNull();
    });

    it('listens on a standalone port, emits listening, and answers plain HTTP with 426', async () => {
        const wss = new WebSocketServer({ port: 0, host: '127.0.0.1' });
        ownedServers.push(wss);
        await waitListening(wss);

        const addr = wss.address() as AddressInfo;
        expect(addr.address).toBe('127.0.0.1');
        expect(addr.port).toBeGreaterThan(0);

        const res = await fetch(`http://127.0.0.1:${addr.port}/`);
        expect(res.status).toBe(426);
        expect(res.headers.get('content-type')).toBe('text/plain');
        expect(res.headers.get('content-length')).toBe('16');
        expect(await res.text()).toBe('Upgrade Required');
    });

    it('creates an HTTPS server when tls options are present', () => {
        const stub = stubListenServer();
        const spy = vi.spyOn(https, 'createServer').mockReturnValue(stub as never);
        const wss = new WebSocketServer({
            port: 8443,
            host: '127.0.0.1',
            backlog: 511,
            tls: { cert: 'CERT', key: 'KEY' },
        });
        ownedServers.push(wss);

        expect(spy).toHaveBeenCalledTimes(1);
        expect(spy.mock.calls[0]![0]).toEqual({ cert: 'CERT', key: 'KEY' });
        expect(stub.listen).toHaveBeenCalledWith(8443, '127.0.0.1', 511, expect.any(Function));
        expect(wss.address()).toEqual({ address: '127.0.0.1', family: 'IPv4', port: 8443 });
    });

    it('creates an HTTPS server from top-level cert and key', () => {
        const stub = stubListenServer();
        const spy = vi.spyOn(https, 'createServer').mockReturnValue(stub as never);
        const wss = new WebSocketServer({
            port: 8443,
            host: '127.0.0.1',
            cert: 'CERT',
            key: 'KEY',
        } as never);
        ownedServers.push(wss);

        expect(spy.mock.calls[0]![0]).toEqual({ cert: 'CERT', key: 'KEY' });
    });

    it('forwards a listen error from the owned HTTP server', async () => {
        const blocker = http.createServer();
        httpServers.push(blocker);
        const port = await listen(blocker);
        const wss = new WebSocketServer({ port, host: '127.0.0.1' });
        ownedServers.push(wss);

        const err = await new Promise<Error>((resolve) => {
            wss.once('error', resolve);
        });
        expect((err as NodeJS.ErrnoException).code).toBe('EADDRINUSE');
    });
});

describe('WebSocketServer.address', () => {
    it('returns the listening address of an attached external server', async () => {
        const server = http.createServer();
        httpServers.push(server);
        const port = await listen(server);
        const wss = new WebSocketServer({ server });
        ownedServers.push(wss);

        const addr = wss.address() as AddressInfo;
        expect(addr.address).toBe('127.0.0.1');
        expect(addr.port).toBe(port);
    });

    it('returns null when an external server has no address method', () => {
        const server = {
            on() {},
            removeListener() {},
        };
        const wss = new WebSocketServer({ server: server as never });
        ownedServers.push(wss);
        expect(wss.address()).toBeNull();
    });
});

describe('WebSocketServer.handleUpgrade', () => {
    it('rejects a non-GET method with 405', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        let accepted = false;
        wss.handleUpgrade(
            upgradeRequest({ method: 'POST' }),
            asSocket(socket),
            Buffer.alloc(0),
            () => {
                accepted = true;
            },
        );
        expect(accepted).toBe(false);
        expect(socket.text).toBe(METHOD_NOT_ALLOWED);
        expect(socket.destroyed).toBe(true);
    });

    it('rejects a missing or non-websocket Upgrade header with 400', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);

        const missing = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { upgrade: undefined } }),
            asSocket(missing),
            Buffer.alloc(0),
            () => {},
        );
        expect(missing.text).toBe(BAD_UPGRADE_HEADER);
        expect(missing.destroyed).toBe(true);

        const httpUpgrade = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { upgrade: 'h2c' } }),
            asSocket(httpUpgrade),
            Buffer.alloc(0),
            () => {},
        );
        expect(httpUpgrade.text).toBe(BAD_UPGRADE_HEADER);
    });

    it('rejects a Connection header that does not contain upgrade', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { connection: 'keep-alive' } }),
            asSocket(socket),
            Buffer.alloc(0),
            () => {},
        );
        expect(socket.text).toBe(BAD_CONNECTION_HEADER);
        expect(socket.destroyed).toBe(true);
    });

    it('rejects a Sec-WebSocket-Version other than 13 with 426', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);

        const old = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-version': '8' } }),
            asSocket(old),
            Buffer.alloc(0),
            () => {},
        );
        expect(old.text).toBe(VERSION_REQUIRED);
        expect(old.destroyed).toBe(true);

        const missing = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-version': undefined } }),
            asSocket(missing),
            Buffer.alloc(0),
            () => {},
        );
        expect(missing.text).toBe(VERSION_REQUIRED);
    });

    it('rejects a missing, non-string, or malformed Sec-WebSocket-Key', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);

        const cases: Array<string | string[] | undefined> = [
            undefined,
            ['dGhlIHNhbXBsZSBub25jZQ=='],
            'short==',
            'AAAAAAAAAAAAAAAAAAAAA==',
            'AAAAAAAAAAAAAAAAAAAAAA',
            '**********************==',
        ];

        for (const key of cases) {
            const socket = new MockSocket();
            wss.handleUpgrade(
                upgradeRequest({ headers: { 'sec-websocket-key': key } }),
                asSocket(socket),
                Buffer.alloc(0),
                () => {},
            );
            expect(socket.text).toBe(BAD_KEY);
            expect(socket.destroyed).toBe(true);
        }
    });

    it('swallows write and destroy errors while aborting', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket({ throwOnWrite: true, throwOnDestroy: true });
        expect(() => {
            wss.handleUpgrade(
                upgradeRequest({ method: 'PUT' }),
                asSocket(socket),
                Buffer.alloc(0),
                () => {},
            );
        }).not.toThrow();
    });

    it('swallows write and destroy errors on the 426 version path', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket({ throwOnWrite: true, throwOnDestroy: true });
        expect(() => {
            wss.handleUpgrade(
                upgradeRequest({ headers: { 'sec-websocket-version': '7' } }),
                asSocket(socket),
                Buffer.alloc(0),
                () => {},
            );
        }).not.toThrow();
    });

    it('accepts a RFC 6455 handshake and tracks the client', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        const req = upgradeRequest({ headers: { upgrade: 'WebSocket' } });
        let acceptedReq: IncomingMessage | undefined;
        wss.handleUpgrade(req, asSocket(socket), Buffer.alloc(0), (ws, request) => {
            acceptedReq = request;
            expect(ws.readyState).toBe(1);
            expect(ws.protocol).toBe('');
            expect(ws.extensions).toBe('');
            expect(wss.clients.has(ws)).toBe(true);
            ws.terminate();
        });

        expect(acceptedReq).toBe(req);
        expect(socket.text).toBe(RFC_SWITCHING);
        expect(socket.timeout).toBe(0);
        expect(socket.noDelay).toBe(true);
        expect(wss.clients.size).toBe(0);
    });

    it('joins an array Connection header before testing for upgrade', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { connection: ['Keep-Alive', 'Upgrade'] } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => ws.terminate(),
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('accepts Connection: keep-alive, Upgrade', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { connection: 'keep-alive, Upgrade' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => ws.terminate(),
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('skips setTimeout and setNoDelay when the socket does not implement them', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        (socket as { setTimeout?: unknown }).setTimeout = undefined;
        (socket as { setNoDelay?: unknown }).setNoDelay = undefined;
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), (ws) =>
            ws.terminate(),
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('selects the first server protocol that the client offered', () => {
        const wss = new WebSocketServer({ noServer: true, protocols: ['chat.v2', 'chat.v1'] });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat.v1, chat.v2' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('chat.v2');
                ws.terminate();
            },
        );
        expect(socket.text).toBe(
            'HTTP/1.1 101 Switching Protocols\r\n' +
                'Upgrade: websocket\r\n' +
                'Connection: Upgrade\r\n' +
                'Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=\r\n' +
                'Sec-WebSocket-Protocol: chat.v2\r\n' +
                '\r\n',
        );
    });

    it('accepts a comma-separated protocols string and a Set', () => {
        const asString = new WebSocketServer({ noServer: true, protocols: 'chat' });
        ownedServers.push(asString);
        const stringSocket = new MockSocket();
        asString.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat' } }),
            asSocket(stringSocket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('chat');
                ws.terminate();
            },
        );
        expect(stringSocket.text).toContain('Sec-WebSocket-Protocol: chat\r\n');

        const asSet = new WebSocketServer({
            noServer: true,
            protocols: new Set(['superchat', 'chat']),
        });
        ownedServers.push(asSet);
        const setSocket = new MockSocket();
        asSet.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat, superchat' } }),
            asSocket(setSocket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('superchat');
                ws.terminate();
            },
        );
        expect(setSocket.text).toContain('Sec-WebSocket-Protocol: superchat\r\n');
    });

    it('uses a protocol selector only when the result was requested', () => {
        const requestedSeen: string[][] = [];
        const wss = new WebSocketServer({
            noServer: true,
            protocols: (requested) => {
                requestedSeen.push(requested);
                return 'chat';
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat, extra' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('chat');
                ws.terminate();
            },
        );
        expect(requestedSeen).toEqual([['chat', 'extra']]);
        expect(socket.text).toContain('Sec-WebSocket-Protocol: chat\r\n');
    });

    it('omits Sec-WebSocket-Protocol when the selector result was not offered', () => {
        const wss = new WebSocketServer({
            noServer: true,
            protocols: () => 'other',
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('');
                ws.terminate();
            },
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('omits Sec-WebSocket-Protocol when nothing overlaps', () => {
        const wss = new WebSocketServer({ noServer: true, protocols: ['json'] });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-protocol': 'chat' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('');
                ws.terminate();
            },
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('negotiates permessage-deflate when offered and enabled', () => {
        const wss = new WebSocketServer({ noServer: true, perMessageDeflate: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-extensions': 'permessage-deflate' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.extensions).toBe('permessage-deflate');
                ws.terminate();
            },
        );
        expect(socket.text).toBe(
            'HTTP/1.1 101 Switching Protocols\r\n' +
                'Upgrade: websocket\r\n' +
                'Connection: Upgrade\r\n' +
                'Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=\r\n' +
                'Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n' +
                '\r\n',
        );
    });

    it('does not advertise permessage-deflate when disabled or not offered', () => {
        const disabled = new WebSocketServer({ noServer: true, perMessageDeflate: false });
        ownedServers.push(disabled);
        const disabledSocket = new MockSocket();
        disabled.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-extensions': 'permessage-deflate' } }),
            asSocket(disabledSocket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.extensions).toBe('');
                ws.terminate();
            },
        );
        expect(disabledSocket.text).toBe(RFC_SWITCHING);

        const noOffer = new WebSocketServer({ noServer: true, perMessageDeflate: true });
        ownedServers.push(noOffer);
        const noOfferSocket = new MockSocket();
        noOffer.handleUpgrade(upgradeRequest(), asSocket(noOfferSocket), Buffer.alloc(0), (ws) => {
            expect(ws.extensions).toBe('');
            ws.terminate();
        });
        expect(noOfferSocket.text).toBe(RFC_SWITCHING);
    });

    it('honors permessage-deflate takeover flags from the config object', () => {
        const wss = new WebSocketServer({
            noServer: true,
            perMessageDeflate: { clientNoContextTakeover: false, serverNoContextTakeover: false },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ headers: { 'sec-websocket-extensions': 'permessage-deflate' } }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => ws.terminate(),
        );
        expect(socket.text).toBe(
            'HTTP/1.1 101 Switching Protocols\r\n' +
                'Upgrade: websocket\r\n' +
                'Connection: Upgrade\r\n' +
                'Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=\r\n' +
                'Sec-WebSocket-Extensions: permessage-deflate\r\n' +
                '\r\n',
        );
    });

    it('writes extensions before protocol when both are selected', () => {
        const wss = new WebSocketServer({
            noServer: true,
            protocols: ['chat'],
            perMessageDeflate: true,
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({
                headers: {
                    'sec-websocket-protocol': 'chat',
                    'sec-websocket-extensions': 'permessage-deflate',
                },
            }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                expect(ws.protocol).toBe('chat');
                expect(ws.extensions).toBe('permessage-deflate');
                ws.terminate();
            },
        );
        expect(socket.text).toBe(
            'HTTP/1.1 101 Switching Protocols\r\n' +
                'Upgrade: websocket\r\n' +
                'Connection: Upgrade\r\n' +
                'Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=\r\n' +
                'Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n' +
                'Sec-WebSocket-Protocol: chat\r\n' +
                '\r\n',
        );
    });

    it('destroys the socket and skips the callback when the 101 write fails', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket({ throwOnWrite: true });
        let accepted = false;
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {
            accepted = true;
        });
        expect(accepted).toBe(false);
        expect(wss.clients.size).toBe(0);
        expect(socket.destroyed).toBe(true);
    });

    it('feeds leftover handshake bytes into the new socket', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        const ping = Buffer.from([0x89, 0x80, 0x00, 0x00, 0x00, 0x00]);
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), ping, (ws) => ws.terminate());
        expect(socket.writes[0]!.toString('utf8')).toBe(RFC_SWITCHING);
        expect(socket.writes[1]!.equals(Buffer.from([0x8a, 0x00]))).toBe(true);
    });

    it('does not emit connection from handleUpgrade in noServer mode', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        let connected = false;
        wss.on('connection', () => {
            connected = true;
        });
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), (ws) =>
            ws.terminate(),
        );
        expect(connected).toBe(false);
    });

    it('ignores options.path inside handleUpgrade itself', () => {
        const wss = new WebSocketServer({ noServer: true, path: '/ws' });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(
            upgradeRequest({ url: '/other' }),
            asSocket(socket),
            Buffer.alloc(0),
            (ws) => {
                ws.terminate();
            },
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });
});

describe('WebSocketServer verifyClient', () => {
    it('accepts when the sync verifier returns true', () => {
        const infos: Array<{ origin?: string; secure: boolean; req: IncomingMessage }> = [];
        const req = upgradeRequest({ headers: { origin: 'https://chat.example' } });
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (info) => {
                infos.push(info);
                return true;
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(req, asSocket(socket), Buffer.alloc(0), (ws) => ws.terminate());
        expect(infos).toEqual([{ origin: 'https://chat.example', secure: false, req }]);
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('rejects a sync verifier false with 401 Unauthorized', () => {
        const wss = new WebSocketServer({ noServer: true, verifyClient: () => false });
        ownedServers.push(wss);
        const socket = new MockSocket();
        let accepted = false;
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {
            accepted = true;
        });
        expect(accepted).toBe(false);
        expect(socket.text).toBe(UNAUTHORIZED);
        expect(socket.destroyed).toBe(true);
    });

    it('marks verify info secure when the socket is encrypted', () => {
        let secure: boolean | undefined;
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (info) => {
                secure = info.secure;
                return true;
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket({ encrypted: true });
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), (ws) =>
            ws.terminate(),
        );
        expect(secure).toBe(true);
    });

    it('accepts when the async verifier calls back true', () => {
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (_info, cb) => {
                cb(true);
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), (ws) =>
            ws.terminate(),
        );
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('rejects an async verifier false with the default 401 body', () => {
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (_info, cb) => {
                cb(false);
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {});
        expect(socket.text).toBe(UNAUTHORIZED);
    });

    it('rejects an async verifier with a custom status and message', () => {
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (_info, cb) => {
                cb(false, 403, 'go away');
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {});
        expect(socket.text).toBe(
            'HTTP/1.1 403 Forbidden\r\n' +
                'Connection: close\r\n' +
                'Content-Length: 7\r\n' +
                'Content-Type: text/plain\r\n' +
                '\r\n' +
                'go away',
        );
    });

    it('uses status text Error and an empty body for an unknown async reject code', () => {
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (_info, cb) => {
                cb(false, 599);
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {});
        expect(socket.text).toBe(
            'HTTP/1.1 599 Error\r\n' +
                'Connection: close\r\n' +
                'Content-Length: 0\r\n' +
                'Content-Type: text/plain\r\n' +
                '\r\n',
        );
    });

    it('waits for a deferred async verifier before writing 101', () => {
        let decide: ((allow: boolean) => void) | undefined;
        const wss = new WebSocketServer({
            noServer: true,
            verifyClient: (_info, cb) => {
                decide = (allow) => cb(allow);
            },
        });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), (ws) =>
            ws.terminate(),
        );
        expect(socket.writes).toEqual([]);
        decide!(true);
        expect(socket.text).toBe(RFC_SWITCHING);
    });
});

describe('WebSocketServer path filtering', () => {
    it('aborts a mismatched path when it is the only upgrade listener', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/ws' });
        ownedServers.push(wss);
        const socket = new MockSocket();
        server.emit(
            'upgrade',
            upgradeRequest({ url: '/other' }),
            asSocket(socket),
            Buffer.alloc(0),
        );
        expect(socket.text).toBe(BAD_PATH);
        expect(socket.destroyed).toBe(true);
    });

    it('leaves a mismatched path alone when another upgrade listener exists', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/ws' });
        ownedServers.push(wss);
        let other = false;
        server.on('upgrade', () => {
            other = true;
        });
        const socket = new MockSocket();
        server.emit(
            'upgrade',
            upgradeRequest({ url: '/other' }),
            asSocket(socket),
            Buffer.alloc(0),
        );
        expect(other).toBe(true);
        expect(socket.writes).toEqual([]);
        expect(socket.destroyed).toBe(false);
    });

    it('matches the path after stripping the query string', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/ws' });
        ownedServers.push(wss);
        const req = upgradeRequest({ url: '/ws?x=1' });
        const socket = new MockSocket();
        const seen: IncomingMessage[] = [];
        wss.on('connection', (ws, request) => {
            seen.push(request);
            ws.terminate();
        });
        server.emit('upgrade', req, asSocket(socket), Buffer.alloc(0));
        expect(seen).toEqual([req]);
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('treats a missing url as /', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/' });
        ownedServers.push(wss);
        const req = upgradeRequest({ url: undefined });
        const socket = new MockSocket();
        let connected = false;
        wss.on('connection', (ws) => {
            connected = true;
            ws.terminate();
        });
        server.emit('upgrade', req, asSocket(socket), Buffer.alloc(0));
        expect(connected).toBe(true);
        expect(socket.text).toBe(RFC_SWITCHING);
    });

    it('rejects a missing url when the configured path is not /', () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server, path: '/ws' });
        ownedServers.push(wss);
        const socket = new MockSocket();
        server.emit(
            'upgrade',
            upgradeRequest({ url: undefined }),
            asSocket(socket),
            Buffer.alloc(0),
        );
        expect(socket.text).toBe(BAD_PATH);
    });
});

describe('WebSocketServer.close', () => {
    it('invokes the callback on the next immediate tick in noServer mode', async () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        let called = false;
        wss.close(() => {
            called = true;
        });
        expect(called).toBe(false);
        await new Promise<void>((resolve) => setImmediate(resolve));
        expect(called).toBe(true);
    });

    it('returns without throwing when noServer close has no callback', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        expect(() => wss.close()).not.toThrow();
    });

    it('detaches the upgrade listener from an external server and still calls back', async () => {
        const server = http.createServer();
        httpServers.push(server);
        const wss = new WebSocketServer({ server });
        ownedServers.push(wss);
        expect(server.listenerCount('upgrade')).toBe(1);
        await closeWss(wss);
        expect(server.listenerCount('upgrade')).toBe(0);
        await closeWss(wss);
        expect(server.listenerCount('upgrade')).toBe(0);
    });

    it('sends 1001 Server shutting down to live clients', () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        const socket = new MockSocket();
        wss.handleUpgrade(upgradeRequest(), asSocket(socket), Buffer.alloc(0), () => {});
        wss.close();
        expect(socket.writes[0]!.toString('utf8')).toBe(RFC_SWITCHING);
        expect(socket.writes[1]!.equals(SHUTDOWN_CLOSE_FRAME)).toBe(true);
    });

    it('swallows a client close that throws', async () => {
        const wss = new WebSocketServer({ noServer: true });
        ownedServers.push(wss);
        wss.clients.add({
            close() {
                throw new Error('boom');
            },
        } as never);
        await closeWss(wss);
    });

    it('forwards the owned HTTP server close callback', async () => {
        const wss = new WebSocketServer({ port: 0, host: '127.0.0.1' });
        ownedServers.push(wss);
        await waitListening(wss);
        await closeWss(wss);
    });
});