import { describe, expect, it } from "bun:test";
import { postmortem } from "@oh-my-pi/pi-utils";

/**
 * Contract for issue #2997: an EPIPE rejection from an IPC `send()` to a worker
 * subprocess (`syscall: "send"`) must be recognizable as a non-fatal, optional-
 * subsystem failure so the global `unhandledRejection` handler can swallow it
 * instead of terminating the session. The predicate must be narrow: a bare
 * EPIPE, or an EPIPE from a stdin/stdout write (`syscall: "write"`), is NOT
 * swallowed — those may signal a real broken pipe to a critical stream.
 */
describe("postmortem.isIpcSendEpipe", () => {
	function makeErr(props: { code?: string; syscall?: string; message?: string }): Error {
		const err = new Error(props.message ?? "broken pipe");
		Object.assign(err, { code: props.code, syscall: props.syscall });
		return err;
	}

	it("matches EPIPE with syscall 'send' (worker IPC send)", () => {
		expect(postmortem.isIpcSendEpipe(makeErr({ code: "EPIPE", syscall: "send" }))).toBe(true);
	});

	it("does not match EPIPE from a stdin/stdout write (syscall 'write')", () => {
		expect(postmortem.isIpcSendEpipe(makeErr({ code: "EPIPE", syscall: "write" }))).toBe(false);
	});

	it("does not match a bare EPIPE without a syscall", () => {
		expect(postmortem.isIpcSendEpipe(makeErr({ code: "EPIPE" }))).toBe(false);
	});

	it("does not match a non-EPIPE error even with syscall 'send'", () => {
		expect(postmortem.isIpcSendEpipe(makeErr({ code: "ENOENT", syscall: "send" }))).toBe(false);
	});

	it("does not match a plain Error with no code/syscall", () => {
		expect(postmortem.isIpcSendEpipe(new Error("boom"))).toBe(false);
	});

	it("does not match nullish/missing errno-style fields gracefully", () => {
		expect(postmortem.isIpcSendEpipe(makeErr({ code: undefined, syscall: undefined }))).toBe(false);
	});
});