import { describe, expect, it, vi } from "vitest";

import { describe, expect, it } from "vitest";

import { createSafeStreamWriter } from "./stream-writer.js";

function createSpy<Args extends unknown[], ReturnValue>(

implementation?: (...args: Args) => ReturnValue,

) {

const calls: Args[] = [];

const spy = (...args: Args) => {

calls.push(args);

return implementation?.(...args) as ReturnValue;

};

spy.calls = calls;

spy.clear = () => {

calls.length = 0;

};

return spy;

}

describe("createSafeStreamWriter", () => {

it("signals broken pipes and closes the writer", () => {

const onBrokenPipe = vi.fn();

const onBrokenPipe = createSpy<[], void>();

const writer = createSafeStreamWriter({ onBrokenPipe });

const stream = {

write: vi.fn(() => {

write: createSpy<[string], boolean>(() => {

const err = new Error("EPIPE") as NodeJS.ErrnoException;

err.code = "EPIPE";

throw err;

expect(writer.writeLine(stream, "hello")).toBe(false);

expect(writer.isClosed()).toBe(true);

expect(onBrokenPipe).toHaveBeenCalledTimes(1);

expect(onBrokenPipe.calls).toHaveLength(1);

onBrokenPipe.mockClear();

onBrokenPipe.clear();

expect(writer.writeLine(stream, "again")).toBe(false);

expect(onBrokenPipe).toHaveBeenCalledTimes(0);

expect(onBrokenPipe.calls).toHaveLength(0);

});

it("treats broken pipes from beforeWrite as closed", () => {

const onBrokenPipe = vi.fn();

const onBrokenPipe = createSpy<[], void>();

const writer = createSafeStreamWriter({

onBrokenPipe,

beforeWrite: () => {

throw err;

},

});

const stream = { write: vi.fn(() => true) } as unknown as NodeJS.WriteStream;

const stream = {

write: createSpy<[string], boolean>(() => true),

} as unknown as NodeJS.WriteStream;

expect(writer.write(stream, "hi")).toBe(false);

expect(writer.isClosed()).toBe(true);

expect(onBrokenPipe).toHaveBeenCalledTimes(1);

expect(onBrokenPipe.calls).toHaveLength(1);

});

});