import { test } from "node:test";
import assert from "node:assert/strict";
import amqp from "amqplib";

import { connectAmqp } from "../dist/broker-amqp.js";
import { useBroker } from "@novox/mesh-sdk/messaging";
import { emit, on, type Event } from "@novox/mesh-sdk/events";

// Binding conformance: does the mesh-tools AMQP *adapter* honour the ADR 0047 wire contract —
// headers on the wire, a body that is only the payload, persistent messages, a durable per-consumer
// queue, dead-letter, poison handling? This tests the adapter in isolation, against a disposable
// broker that stands in for the one the mesh hosts (ADR 0001). It is NOT an event test of the mesh:
// that lives in a full lab scenario where the mesh raises the broker as substrate. Requires
// $MESH_BROKER_URL (a throwaway broker); skipped, never failed, when it is not set.
const url = process.env.MESH_BROKER_URL;

test("an event rides the wire with ADR 0047 headers and a body that is only the payload", { skip: !url }, async () => {
  const sub = await connectAmqp(url!);
  const pub = await connectAmqp(url!);

  // The consumer's identity names its durable queue (<node>.<module>.events).
  process.env.MESH_NODE = "lab";
  process.env.MESH_MODULE = "audit-logger";
  useBroker(() => sub);
  const got: Event[] = [];
  await on("#", async (e) => void got.push(e));
  await delay(200); // let the binding settle before publishing

  // The emitter is a different module on the same node.
  process.env.MESH_MODULE = "umami";
  useBroker(() => pub);
  await emit("module.umami.site.created", { domain: "my-app" }, { causationId: "cmd-1" });

  await waitFor(() => got.length > 0, 4000);
  const e = got[0];
  assert.equal(e.type, "module.umami.site.created");
  assert.equal(e.source, "umami"); // x-source — read from a header, not the body
  assert.equal(e.node, "lab"); // x-node
  assert.ok(e.id, "x-event-id present"); // the handle a consumer dedups on
  assert.equal(e.causationId, "cmd-1"); // x-causation-id round-trips
  assert.match(e.at, /^\d{4}-\d{2}-\d{2}T/); // x-time, RFC-3339
  assert.deepEqual(e.body, { domain: "my-app" }); // provenance never leaked into the body

  // The durable per-consumer queue exists and is bound — a passive assert throws if it does not.
  const probe = await amqp.connect(url!);
  const pch = await probe.createChannel();
  await pch.checkQueue("lab.audit-logger.events");
  await probe.close();

  await sub.close();
  await pub.close();
  delete process.env.MESH_NODE;
  delete process.env.MESH_MODULE;
});

test("a handler that keeps failing dead-letters the event past the redelivery limit", { skip: !url }, async () => {
  const module = `flaky-${Date.now()}`;
  const c = await connectAmqp(url!);
  process.env.MESH_NODE = "lab";
  process.env.MESH_MODULE = module;
  useBroker(() => c);

  let attempts = 0;
  await on("module.test.boom", async () => {
    attempts++;
    throw new Error("boom");
  });
  await delay(200);

  await emit("module.test.boom", { n: 1 });

  // First delivery requeues once; the redelivered copy is dead-lettered — two attempts, then it
  // leaves the consumer queue for good.
  await waitFor(() => attempts >= 2, 5000);
  await delay(300);
  assert.equal(attempts, 2, "attempted twice, not looping forever");

  // The poison event is retained on the dead-letter queue for inspection, not vanished.
  const probe = await amqp.connect(url!);
  const pch = await probe.createChannel();
  const dead = await pch.get("mesh.events.dead", { noAck: true });
  assert.ok(dead, "the rejected event is on mesh.events.dead");
  assert.equal((dead as amqp.GetMessage).fields.routingKey, "module.test.boom");
  await probe.close();

  await c.close();
  delete process.env.MESH_NODE;
  delete process.env.MESH_MODULE;
});

test("an undecodable event body is dead-lettered, not looped and not silently swallowed", { skip: !url }, async () => {
  const module = `poison-${Date.now()}`;
  const c = await connectAmqp(url!);
  process.env.MESH_NODE = "lab";
  process.env.MESH_MODULE = module;
  useBroker(() => c);

  // Drain any earlier dead events so the assert below sees only this test's.
  const drain = await amqp.connect(url!);
  const dch = await drain.createChannel();
  await dch.purgeQueue("mesh.events.dead");

  let handlerRuns = 0;
  await on("module.poison.raw", async () => void handlerRuns++);
  await delay(200);

  // Publish a body that is not JSON straight onto the events exchange — a malformed emitter. A
  // confirm channel, waited on, so the broker has the message before the connection closes.
  const raw = await amqp.connect(url!);
  const rch = await raw.createConfirmChannel();
  rch.publish("mesh.events", "module.poison.raw", Buffer.from("this is not json{"), {
    persistent: true,
    headers: { "x-event-id": "poison-1", "x-source": "bad", "x-node": "lab" },
  });
  await rch.waitForConfirms();
  await raw.close();

  // The handler never ran (the body never decoded), and the message is on the dead queue — set
  // aside for inspection, not stuck redelivering forever.
  await delay(600);
  assert.equal(handlerRuns, 0, "a body that never decodes never reaches the handler");
  const dead = await dch.get("mesh.events.dead", { noAck: true });
  assert.ok(dead, "the poison event is retained on mesh.events.dead");
  assert.equal((dead as amqp.GetMessage).fields.routingKey, "module.poison.raw");
  await drain.close();

  await c.close();
  delete process.env.MESH_NODE;
  delete process.env.MESH_MODULE;
});

function delay(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

async function waitFor(cond: () => boolean, ms: number): Promise<void> {
  const start = Date.now();
  while (!cond()) {
    if (Date.now() - start > ms) throw new Error("condition not met in time");
    await delay(25);
  }
}