"use strict";

import assert from "node:assert";
import { test } from "node:test";
import { EventEmitter } from "node:events";
import {
  isClientAbortError,
  shouldSwallowUncaught,
  attachRequestStreamGuards,
  installProcessCrashGuard,
} from "../../scripts/dev/httpClientAbortGuard.mjs";
import * as sharedGuard from "../../src/shared/utils/httpClientAbortGuard.mjs";

// The dev server imports from scripts/dev/httpClientAbortGuard.mjs, while the
// TypeScript servers (apiBridgeServer, liveServer, embedWsProxy) import from
// src/shared/utils/httpClientAbortGuard.mjs. The scripts/dev copy must be a pure
// re-export of the shared implementation — verify they are the SAME functions
// (single source of truth, no drift).
test("scripts/dev guard re-exports the shared src implementation (single source of truth)", () => {
  assert.equal(isClientAbortError, sharedGuard.isClientAbortError);
  assert.equal(shouldSwallowUncaught, sharedGuard.shouldSwallowUncaught);
  assert.equal(attachRequestStreamGuards, sharedGuard.attachRequestStreamGuards);
  assert.equal(installProcessCrashGuard, sharedGuard.installProcessCrashGuard);
  // And the shared module exposes everything the TS servers rely on.
  for (const name of [
    "isClientAbortError",
    "shouldSwallowUncaught",
    "attachRequestStreamGuards",
    "installProcessCrashGuard",
  ]) {
    assert.equal(typeof sharedGuard[name], "function", `shared guard must export ${name}`);
  }
});

// Minimal stand-ins for IncomingMessage / ServerResponse that expose the
// `error` event (Node's http streams are EventEmitters).
function makeReq() {
  return new EventEmitter();
}
function makeRes() {
  const res = new EventEmitter();
  res.end = () => res;
  res.write = () => true;
  return res;
}

test("isClientAbortError matches the exact production crash signature", () => {
  // Reproduces the Node `abortIncoming` error seen in the app log:
  //   uncaughtException: aborted / Error: aborted (no code)
  const aborted = Object.assign(new Error("aborted"), {});
  assert.equal(isClientAbortError(aborted), true, "plain 'aborted' must be absorbed");

  for (const code of [
    "ECONNRESET",
    "EPIPE",
    "ERR_STREAM_PREMATURE_CLOSE",
    "ECONNABORTED",
    "ETIMEDOUT",
    "ENOTCONN",
    "ECANCELED",
  ]) {
    const err = Object.assign(new Error(code), { code });
    assert.equal(isClientAbortError(err), true, `${code} must be absorbed`);
  }
});

test("isClientAbortError rejects genuine server errors", () => {
  const real = Object.assign(new Error("boom"), { code: "ENOSPC" });
  assert.equal(isClientAbortError(real), false);
  const noCode = new Error("something else entirely");
  assert.equal(isClientAbortError(noCode), false);
});

test("attachRequestStreamGuards swallows a client abort on req without throwing", () => {
  const req = makeReq();
  const res = makeRes();
  attachRequestStreamGuards(req, res);

  // Must NOT throw / bubble as uncaughtException.
  assert.doesNotThrow(() => {
    req.emit("error", Object.assign(new Error("aborted"), {}));
    res.emit("error", Object.assign(new Error("aborted"), {}));
  });
});

test("attachRequestStreamGuards is idempotent (no double listeners / no throw)", () => {
  const req = makeReq();
  const res = makeRes();
  attachRequestStreamGuards(req, res);
  assert.doesNotThrow(() => attachRequestStreamGuards(req, res));
  // A second abort must also be absorbed quietly.
  assert.doesNotThrow(() => {
    req.emit("error", Object.assign(new Error("ECONNRESET"), { code: "ECONNRESET" }));
  });
});

test("shouldSwallowUncaught absorbs the real 'aborted' uncaughtException signature", () => {
  // The exact error Node raises from http.Server#abortIncoming in the log:
  //   uncaughtException: aborted / Error: aborted (no code)
  const abortErr = new Error("aborted");
  assert.equal(shouldSwallowUncaught(abortErr, "uncaughtException"), true);
  assert.equal(shouldSwallowUncaught(abortErr, undefined), true);
  assert.equal(
    shouldSwallowUncaught(Object.assign(new Error("ECONNRESET"), { code: "ECONNRESET" }), "uncaughtException"),
    true
  );
});

test("shouldSwallowUncaught preserves crash semantics for genuine errors", () => {
  const realErr = new Error("genuine failure");
  assert.equal(shouldSwallowUncaught(realErr, "uncaughtException"), false);
  const realErr2 = Object.assign(new Error("disk full"), { code: "ENOSPC" });
  assert.equal(shouldSwallowUncaught(realErr2, "uncaughtException"), false);
});

test("installProcessCrashGuard does not throw on import and is idempotent", () => {
  assert.doesNotThrow(() => installProcessCrashGuard(() => {}));
  assert.doesNotThrow(() => installProcessCrashGuard(() => {}));
});