import { describe, expect, it, vi } from 'vitest';
import {
    addSocketListener,
    closeInfo,
    normalizeReconnect,
    rawToString,
    unwrapEventPayload,
    unwrapMessagePayload,
    WEBSOCKET_CLOSED,
    WEBSOCKET_OPEN,
} from '../src/client/websocket-utils';
import type { WebSocketLike } from '../src/client/websocket-types';

function stubSocket(extra: Partial<WebSocketLike> = {}): WebSocketLike {
    return {
        readyState: 0,
        send() {},
        close() {},
        ...extra,
    };
}

describe('websocket readyState constants', () => {
    it('matches the standard WebSocket readyState values', () => {
        expect(WEBSOCKET_OPEN).toBe(1);
        expect(WEBSOCKET_CLOSED).toBe(3);
    });
});

describe('normalizeReconnect', () => {
    it('treats a disabled or omitted value as no reconnect policy', () => {
        expect(normalizeReconnect(false)).toBeNull();
        expect(normalizeReconnect(undefined)).toBeNull();
    });

    it('turns a boolean enable flag into an empty options object', () => {
        expect(normalizeReconnect(true)).toEqual({});
    });

    it('returns the given reconnect options object unchanged', () => {
        const options = { retries: 4, minDelayMs: 250, maxDelayMs: 8_000 };
        expect(normalizeReconnect(options)).toBe(options);
        expect(normalizeReconnect({ retries: 0 })).toEqual({ retries: 0 });
        expect(normalizeReconnect({})).toEqual({});
    });
});

describe('addSocketListener', () => {
    it('binds and unbinds through addEventListener when present', () => {
        const listener = vi.fn();
        const socket = stubSocket({
            addEventListener: vi.fn(),
            removeEventListener: vi.fn(),
            on: vi.fn(),
        });

        const off = addSocketListener(socket, 'message', listener);

        expect(socket.addEventListener).toHaveBeenCalledTimes(1);
        expect(socket.addEventListener).toHaveBeenCalledWith('message', listener);
        expect(socket.on).not.toHaveBeenCalled();

        off();
        expect(socket.removeEventListener).toHaveBeenCalledTimes(1);
        expect(socket.removeEventListener).toHaveBeenCalledWith('message', listener);
    });

    it('does not throw on cleanup when removeEventListener is absent', () => {
        const socket = stubSocket({ addEventListener: vi.fn() });
        const off = addSocketListener(socket, 'open', vi.fn());
        expect(off).not.toThrow();
    });

    it('binds through on() and unbinds through off() when addEventListener is missing', () => {
        const listener = vi.fn();
        const socket = stubSocket({
            on: vi.fn(),
            off: vi.fn(),
            removeListener: vi.fn(),
        });

        const off = addSocketListener(socket, 'close', listener);

        expect(socket.on).toHaveBeenCalledTimes(1);
        expect(socket.on).toHaveBeenCalledWith('close', listener);

        off();
        expect(socket.off).toHaveBeenCalledTimes(1);
        expect(socket.off).toHaveBeenCalledWith('close', listener);
        expect(socket.removeListener).not.toHaveBeenCalled();
    });

    it('falls back to removeListener when off() is absent', () => {
        const listener = vi.fn();
        const socket = stubSocket({
            on: vi.fn(),
            removeListener: vi.fn(),
        });

        const off = addSocketListener(socket, 'error', listener);
        off();

        expect(socket.removeListener).toHaveBeenCalledTimes(1);
        expect(socket.removeListener).toHaveBeenCalledWith('error', listener);
    });

    it('cleanup is a no-op when on() has neither off nor removeListener', () => {
        const socket = stubSocket({ on: vi.fn() });
        const off = addSocketListener(socket, 'message', vi.fn());
        expect(off).not.toThrow();
    });

    it('returns a no-op cleanup when the socket has no listener APIs', () => {
        const off = addSocketListener(stubSocket(), 'open', vi.fn());
        expect(off).not.toThrow();
    });
});

describe('unwrapMessagePayload', () => {
    it('returns the data field from a JSON object envelope', () => {
        expect(unwrapMessagePayload({ data: '{"ok":true}' })).toBe('{"ok":true}');
        expect(unwrapMessagePayload({ data: { text: 'hi' } })).toEqual({ text: 'hi' });
        expect(unwrapMessagePayload({ data: 0 })).toBe(0);
        expect(unwrapMessagePayload({ data: undefined })).toBeUndefined();
    });

    it('returns the original value when it is not a data envelope', () => {
        expect(unwrapMessagePayload('raw-text')).toBe('raw-text');
        expect(unwrapMessagePayload(null)).toBeNull();
        expect(unwrapMessagePayload([{ data: 1 }])).toEqual([{ data: 1 }]);
        expect(unwrapMessagePayload({ type: 'message' })).toEqual({ type: 'message' });
    });
});

describe('unwrapEventPayload', () => {
    it('returns the error field from a JSON object envelope', () => {
        expect(unwrapEventPayload({ error: 'socket failed' })).toBe('socket failed');
        expect(unwrapEventPayload({ error: { message: 'boom' } })).toEqual({ message: 'boom' });
        expect(unwrapEventPayload({ error: undefined })).toBeUndefined();
    });

    it('returns the original value when it is not an error envelope', () => {
        expect(unwrapEventPayload('plain-error')).toBe('plain-error');
        expect(unwrapEventPayload(null)).toBeNull();
        expect(unwrapEventPayload([{ error: 1 }])).toEqual([{ error: 1 }]);
        expect(unwrapEventPayload({ type: 'error' })).toEqual({ type: 'error' });
    });
});

describe('rawToString', () => {
    it('returns strings unchanged', () => {
        expect(rawToString('{"echo":1}')).toBe('{"echo":1}');
        expect(rawToString('')).toBe('');
    });

    it('decodes ArrayBuffer and ArrayBufferView payloads as UTF-8', () => {
        const bytes = Uint8Array.from([0x68, 0x69]);
        expect(rawToString(bytes.buffer)).toBe('hi');
        expect(rawToString(bytes)).toBe('hi');
        expect(rawToString(Buffer.from([0x68, 0x69]))).toBe('hi');
        expect(rawToString(new DataView(bytes.buffer))).toBe('hi');
        expect(rawToString(Uint8Array.from([0x21, 0x68, 0x69, 0x21]).subarray(1, 3))).toBe('hi');
        expect(rawToString(new ArrayBuffer(0))).toBe('');
    });

    it('rejects Blob payloads that cannot be read synchronously', () => {
        expect(() => rawToString(new Blob(['hi']))).toThrow(
            'Blob WebSocket messages are not supported synchronously',
        );
    });

    it('uses toString() on objects and String() on primitives', () => {
        expect(rawToString({ toString: () => 'from-toString' })).toBe('from-toString');
        expect(rawToString([1, 2])).toBe('1,2');
        expect(rawToString({ a: 1 })).toBe('[object Object]');
        expect(rawToString(42)).toBe('42');
        expect(rawToString(false)).toBe('false');
        expect(rawToString(null)).toBe('null');
        expect(rawToString(undefined)).toBe('undefined');
    });
});

describe('closeInfo', () => {
    it('reads code and reason from a CloseEvent-like object', () => {
        expect(closeInfo([{ code: 1000, reason: 'normal', wasClean: true }])).toEqual({
            code: 1000,
            reason: 'normal',
        });
        expect(closeInfo([{ code: 1001 }])).toEqual({
            code: 1001,
            reason: undefined,
        });
        expect(closeInfo([{ reason: 'going away' }])).toEqual({
            code: undefined,
            reason: 'going away',
        });
        expect(closeInfo([{ code: '1000', reason: 1 }])).toEqual({
            code: undefined,
            reason: undefined,
        });
    });

    it('reads positional Node-style close arguments', () => {
        expect(closeInfo([1006, 'abnormal'])).toEqual({
            code: 1006,
            reason: 'abnormal',
        });
        expect(closeInfo([1000])).toEqual({
            code: 1000,
            reason: undefined,
        });
        expect(closeInfo(['1000', 1])).toEqual({
            code: undefined,
            reason: undefined,
        });
        expect(closeInfo([])).toEqual({
            code: undefined,
            reason: undefined,
        });
        expect(closeInfo([[1000, 'nested']])).toEqual({
            code: undefined,
            reason: undefined,
        });
    });
});