import { NextResponse } from "next/server";
import { testRouteDenied } from "../_guard";

export const dynamic = "force-dynamic";

// E2E test harness only. Counts uncaughtException + unhandledRejection
// events seen by the dev-server's Node process so a spec can assert that
// "Controller is already closed" no longer leaks out of the streaming job
// pipeline when the consumer disconnects.
//
// The process-level handler is installed once on first module load. It's
// gated by the test-fixture TRANSCRIPTS_DIR path so production-shaped
// installs never see it.

type CountState = {
  uncaught: number;
  unhandled: number;
  messages: string[];
};

declare global {
  // eslint-disable-next-line no-var
  var __yttUncaughtCount__: CountState | undefined;
}

function isTestEnv(): boolean {
  const dir = process.env.TRANSCRIPTS_DIR ?? "";
  return dir.endsWith("test-transcripts");
}

function getState(): CountState {
  if (!globalThis.__yttUncaughtCount__) {
    globalThis.__yttUncaughtCount__ = {
      uncaught: 0,
      unhandled: 0,
      messages: [],
    };
    if (isTestEnv()) {
      process.on("uncaughtException", (err) => {
        const s = globalThis.__yttUncaughtCount__!;
        s.uncaught++;
        s.messages.push(`uncaught: ${(err as Error)?.message ?? String(err)}`);
        if (s.messages.length > 50) s.messages.shift();
      });
      process.on("unhandledRejection", (reason) => {
        const s = globalThis.__yttUncaughtCount__!;
        s.unhandled++;
        s.messages.push(
          `unhandled: ${(reason as Error)?.message ?? String(reason)}`,
        );
        if (s.messages.length > 50) s.messages.shift();
      });
    }
  }
  return globalThis.__yttUncaughtCount__;
}

export async function GET() {
  const denied = testRouteDenied();
  if (denied) return denied;
  const state = getState();
  return NextResponse.json({
    uncaught: state.uncaught,
    unhandled: state.unhandled,
    messages: state.messages.slice(),
  });
}

export async function DELETE() {
  const denied = testRouteDenied();
  if (denied) return denied;
  const state = getState();
  state.uncaught = 0;
  state.unhandled = 0;
  state.messages.length = 0;
  return NextResponse.json({ ok: true });
}