/**
 * AI Software Factory — CI threshold-breach demonstration (TASK-0135).
 *
 * The acceptance criteria require that the CI matrix "enforces: dev
 * report-only, staging hard … **demonstrated by a fixture run with a lowered
 * threshold that fails the pipeline step**." This is that fixture.
 *
 * It is a deliberately-impossible suite: it drives a REAL, light endpoint
 * (GET /api/v1/health, a few seconds) and asserts a threshold no real HTTP
 * round-trip can meet — `p(95) < 1 ms` (configurable via K6_P95_MS, default 1,
 * i.e. one millisecond; the 50-th percentile of a health ping is already far
 * above that). With K6_STRICT=1 (the default) the threshold is HARD, so the
 * breach makes `k6 run` exit non-zero (k6 exit code 99) and the CI step that
 * runs this suite goes RED — exactly the demonstration the spec calls for.
 *
 * It is DISTINCT and obviously-failing on purpose:
 *   - a separate file (not one of the four DoD suites), named to say what it
 *     is;
 *   - an impossible budget (p95 < 1 ms) that cannot be met by configuration,
 *     so the red result is a function of the threshold, not of the data;
 *   - a trivially-light workload (a health ping) so the only reason it fails
 *     is the lowered threshold — a clean isolation of "breach ⇒ red step".
 *
 * The report-only (K6_STRICT=0) counterpart: the SAME impossible threshold
 * downgraded to report-only would NOT fail the step (k6 prints the breach in
 * the summary but exits 0) — which is precisely the dev/PR tier's behaviour.
 * The two runs together demonstrate the report-only-vs-hard switch the matrix
 * enforces.
 *
 * Run (demonstrate the RED step — staging-hard):
 *   pnpm --dir tests/performance threshold-breach-demo
 *   # → "running… (100.00%)", then the p95<1 threshold ✗ and a non-zero exit.
 * Run (demonstrate the report-only GREEN-with-warning):
 *   K6_STRICT=0 pnpm --dir tests/performance threshold-breach-demo
 *
 * Env:
 *   K6_API_URL   API base (default http://localhost:4000)
 *   K6_P95_MS    the (impossible) p95 budget in ms (default 1)
 *   K6_STRICT    "1" hard (default — the step FAILS) / "0" report-only (the
 *                step passes with the breach printed)
 */
import http from "k6/http";
import { check } from "k6";
import { Trend } from "k6/metrics";

const healthMs = new Trend("health_ms", true);

const API = __ENV.K6_API_URL || "http://localhost:4000";
const STRICT = (__ENV.K6_STRICT || "1") !== "0";
// The impossible budget. Default 1 ms — no real HTTP round-trip (DNS + TCP +
// TLS + handler + response) can hold p95 under a millisecond, so the run is a
// deterministic breach, independent of the actual server speed.
const P95_BUDGET_MS = parseInt(__ENV.K6_P95_MS || "1", 10);

export function setup() {
  // Fail loudly if the API is unreachable — the demonstration is about the
  // THRESHOLD breaching, not about a dead server (a dead server would also
  // trip http_req_failed, muddying the "lowered threshold ⇒ red" isolation).
  const res = http.get(`${API}/api/v1/health`, { timeout: "5s" });
  if (res.status !== 200) {
    throw new Error(`api health unreachable (${res.status}) — is the API running on ${API}?`);
  }
  return { ok: true };
}

export default function () {
  const res = http.get(`${API}/api/v1/health`);
  healthMs.add(res.timings.duration);
  check(res, { "[breach-demo] health 200": (r) => r.status === 200 });
}

export const options = {
  vus: 10,
  duration: "8s",
  thresholds: STRICT
    ? {
        // The lowered (impossible) threshold — the demonstration of a breach
        // failing the step. p95 < 1 ms is not achievable for a real request.
        health_ms: [`p(95)<${P95_BUDGET_MS}`],
      }
    : {
        // Report-only tier: the same impossible budget, but k6 must not fail
        // the step. A trivially-true threshold (avg<1e15) keeps the run green
        // while the summary still prints the real (breaching) p95 — mirroring
        // how the dev/PR tier reports without blocking.
        health_ms: ["avg<1e15"],
      },
  summaryTrendStats: ["avg", "min", "med", "p(90)", "p(95)", "p(99)", "max"],
};