// src/integrations/paloalto/metrics.js
//
// Thin POST wrappers around Prisma SD-WAN's monitor v2.0 metrics
// API. All endpoints are POST — Prisma's monitor API always accepts
// a JSON body with `start_time` + `interval` + `metrics` + `filter`,
// even for what would idiomatically be a GET on other systems. See
// https://pan.dev/sdwan/api/metrics/ for the endpoint catalog.
//
// Endpoint / body-shape notes verified against a live SASE tenant.
// This section is the historical record of what broke and how the
// tenant's schema differs from pan.dev — read before changing any
// wrapper, because "helpful cleanup" here almost always regresses.
//
//   - LQM point metrics live at a DEDICATED endpoint:
//       POST /sdwan/monitor/v2.0/api/monitor/lqm_point_metrics
//     NOT `sys_point_metrics` — that endpoint is for system metrics
//     (CPU, Memory, Disk) and its schema rejects `filter.waninterface`
//     ("is not defined in the schema"). LQM has its own endpoint.
//     Metric names on the LQM endpoint carry the `PointMetric`
//     suffix: `LqmLatencyPointMetric`, `LqmJitterPointMetric`,
//     `LqmPktLossPointMetric` (Pkt, not Packet), `LqmMosPointMetric`.
//
//   - LQM body shape on this tenant:
//         `end_time` → rejected as "not defined in the schema"
//           (endpoint interprets window as [start_time, now))
//     Filter shape:
//         `filter.site` — ARRAY of strings. Live 400 was
//                          "$.filter.site: string found, array expected".
//                          This is OPPOSITE to sys_point_metrics,
//                          which wants a plain string.
//         `filter.path` — array. This is the KEY THAT WORKS on
//                          lqm_point_metrics for scoping to
//                          specific circuits — even though the
//                          circuit ids we pass are waninterface
//                          ids from /sites/{id}/waninterfaces.
//                          The LIVEcommunity working example uses
//                          this exact shape:
//                            filter: { site: [id], path: [wi_id] }
//                          Both `wan_interfaces` (plural + underscore)
//                          and `waninterface` (sys_point_metrics
//                          variant) are rejected as "not defined in
//                          the schema" on this tenant.
//     No `elements` filter (that's a sys_point_metrics quirk).
//
//   - `metrics[].statistics` is a PLURAL array (`["average"]` /
//     `["max"]`), not the singular `statistic`.
//
//   - `metrics[].unit` is case-sensitive: `milliseconds`, `Percentage`,
//     `gauge`, `count`.
//
//   - Healthscore on this tenant: v2.0 aiops/health is a DEAD END.
//     Confirmed via prismaProbe try-shapes:
//         v2.0 `metrics: [...]`         → rejected ("not defined")
//         v2.0 with `end_time` removed  → 400 "end_time is required"
//         v2.0 with `end_time` added +  → same "$.metrics: not defined"
//         v2.1 aiops/aggregates         → requires app_id + aggregates
//         v2.6 unified /monitor/metrics → ✅ 200 OK (only winner)
//     We use `POST /sdwan/monitor/v2.6/api/monitor/metrics` with the
//     standard `metrics: [{Healthscore}]` + `filter: {site: [id]}`.
//     This endpoint accepts filter.site as an ARRAY and returns a
//     per-site healthscore in the response.
//
//   - `interval` must be one of Prisma's canonical bucket sizes:
//     `10sec`, `1min`, `5min`, `1hour`, `1day`. `15min` etc.
//     yield HTTP 400 with SCHEMA_CHECK_FAIL on `$.interval`.
//
//   - Alarms live at `POST /sdwan/v3.7/api/events/query`, NOT
//     `/sdwan/monitor/v2.0/api/monitor/alarms` (that endpoint
//     404s "ROUTE_NOT_FOUND" on the observed tenant).
//
// All wrappers return `null` on any failure and log the error with
// a preview of the response body so shape drift is diagnosable
// without cranking LOG_LEVEL=debug. Higher layers absorb per-metric
// failures via `Promise.allSettled`.

import { paloAltoAxios } from './client.js';
import { logger } from '../../utils/logger.js';

// Prisma metric-name catalog for the LQM (Link Quality Monitoring)
// bucket. Short JS keys → { name, unit } for the API body.
//
// Names carry the `PointMetric` suffix because this maps to the
// dedicated `lqm_point_metrics` endpoint (NOT `sys_point_metrics`).
// The unit strings are verified via 400 SCHEMA_CHECK_FAIL responses
// when they drift and are case-sensitive:
//   - `milliseconds` (lowercase) → latency, jitter
//   - `percentage` (lowercase — NOT `Percentage`, verified via
//                   prismaProbe try-shapes lqm-loss on 2026-07-09
//                   which returned 400 METRIC_UNIT_NOT_SUPPORTED for
//                   every capitalized/alternate variant) → loss
//   - `count` → mos
// If Prisma ever rejects a unit here, re-run the matrix probe:
//   `node scripts/prismaProbe.js try-shapes lqm-loss <site> <wis>`.
export const LQM_METRIC_NAMES = Object.freeze({
  latency: { name: 'LqmLatencyPointMetric', unit: 'milliseconds' },
  jitter:  { name: 'LqmJitterPointMetric',  unit: 'milliseconds' },
  loss:    { name: 'LqmPktLossPointMetric', unit: 'percentage' },
  mos:     { name: 'LqmMosPointMetric',     unit: 'count' },
});

// ──────────────────────────────────────────────
// URL helpers — SASE and legacy have different prefixes
// ──────────────────────────────────────────────

function isSase() {
  return String(process.env.PRISMA_AUTH_MODE || 'sase').toLowerCase().trim() === 'sase';
}

function monitorPath(endpoint) {
  return isSase()
    ? `/sdwan/monitor/v2.0/api/monitor/${endpoint}`
    : `/v2.0/api/monitor/${endpoint}`;
}

// v2.6 unified monitor/metrics endpoint. The observed tenant only
// serves healthscore correctly here — v2.0 aiops/health is a dead
// end (see the top-of-file schema notes).
function metricsV26Path() {
  return isSase()
    ? '/sdwan/monitor/v2.6/api/monitor/metrics'
    : '/v2.6/api/monitor/metrics';
}

// Events endpoint (SASE v3.7 is the current top of the docs). Used
// for alarm retrieval — the older `/monitor/alarms` path 404s on
// the SASE surface.
function eventsQueryPath() {
  return isSase()
    ? '/sdwan/v3.7/api/events/query'
    : '/v3.7/api/events/query';
}

// ──────────────────────────────────────────────
// Time-window helpers
// ──────────────────────────────────────────────

function windowStart(minutes) {
  return new Date(Date.now() - minutes * 60 * 1000).toISOString();
}

function nowIso() {
  return new Date().toISOString();
}

// Prisma's valid `interval` enum (verified via HTTP 400 error message).
// `15min`, `30min` etc. are NOT accepted — snap up to the next valid
// bucket (1hour) rather than silently down-sampling.
//
// Used for LQM and healthscore. Those endpoints return a SINGLE
// aggregated value per path/site (regardless of interval), so the
// interval only affects Prisma's internal downsampling — coarser is
// fine, and 1day for a 24h window is the cheapest ask.
function pickInterval(minutes) {
  if (minutes <= 1)  return '1min';
  if (minutes <= 5)  return '5min';
  if (minutes <  60) return '5min';    // 15-minute default now snaps to 5min buckets
  if (minutes <= 60) return '1hour';
  return '1day';
}

// App-metric variant. UNLIKE LQM, per-app metrics return the FULL
// datapoint time series (metrics[].series[].data[].datapoints[]) and
// downstream code aggregates {avg, min, max, p95} client-side. That
// only works if the interval is fine enough to capture the transient
// windows we're trying to surface. HAR (2026-07-09) confirms the
// Prisma UI queries `5min` for a 24h window (yielding 288 datapoints
// per metric) — matching that keeps our worst-window statistics
// meaningful. Falling back to `1day` (as `pickInterval` does) would
// collapse the whole series into 1-2 aggregated points and hide the
// exact degradation these checks exist to catch.
function pickAppMetricInterval(minutes) {
  if (minutes <= 1)     return '1min';
  if (minutes <= 5)     return '5min';
  if (minutes <= 60)    return '5min';   // 12 points per hour
  if (minutes <= 1440)  return '5min';   // 24h → 288 points (HAR-confirmed)
  // Beyond 24h, cap the point count with hourly buckets: 7d @ 1h = 168
  // points which is still a manageable payload.
  if (minutes <= 10080) return '1hour';
  return '1day';
}

// Small helper that logs a failed metric call with a response-body
// preview AND (on 4xx) the request body that Prisma rejected — the
// most common failure mode is a metric name or filter key drifting
// on the tenant, and seeing both sides in the same log line makes
// the schema mismatch obvious without cranking LOG_LEVEL=debug.
function logMetricFailure(scope, err) {
  const status = err.response?.status;
  const respPreview = err.response?.data
    ? JSON.stringify(err.response.data).slice(0, 300)
    : '';
  const isSchemaError = status && status >= 400 && status < 500;
  const reqPreview = isSchemaError && err.config?.data
    ? String(err.config.data).slice(0, 500)
    : '';
  const parts = [
    `${scope} failed: ${err.message}`,
    status ? `(HTTP ${status})` : '',
    respPreview ? `— resp: ${respPreview}` : '',
    reqPreview ? `— req: ${reqPreview}` : '',
  ].filter(Boolean);
  logger('paloalto:metrics', parts.join(' '), 'warn');
}

// ──────────────────────────────────────────────
// Healthscore (site-level roll-up 0-100)
// ──────────────────────────────────────────────

/**
 * Site healthscore (0-100) over the given window. Uses the v2.6
 * unified monitor/metrics endpoint — the only healthscore endpoint
 * that returned 200 on this tenant (verified via prismaProbe
 * try-shapes; v2.0 aiops/health and v2.1 aiops/aggregates both
 * dead-end on schema errors this tenant enforces).
 *
 * The v2.6 endpoint accepts:
 *   - `metrics: [{ name: 'Healthscore', statistics: ['max'], unit: 'gauge' }]`
 *   - `view: {}`
 *   - `filter: { site: [siteId] }`  — scoped server-side (unlike
 *                                     v2.0 which rejects any filter)
 *   - `interval` + `start_time` (no `end_time`)
 *
 * @param {string} siteId
 * @param {number} windowMinutes default 15
 * @returns {Promise<object|null>} raw response or null on failure
 */
export async function getHealthscore(siteId, windowMinutes = 15) {
  if (!siteId) return null;
  try {
    const res = await paloAltoAxios.post(metricsV26Path(), {
      start_time: windowStart(windowMinutes),
      interval: pickInterval(windowMinutes),
      metrics: [{
        name: 'Healthscore',
        statistics: ['max'],
        unit: 'gauge',
      }],
      view: {},
      filter: { site: [String(siteId)] },
    });
    return res.data || null;
  } catch (err) {
    logMetricFailure(`getHealthscore(${siteId})`, err);
    return null;
  }
}

// ──────────────────────────────────────────────
// LQM point metrics (per-path latency / jitter / loss / MOS)
// ──────────────────────────────────────────────

/**
 * Fetch one of the four LQM point metrics over the given window.
 * `metricKey` is one of the keys of LQM_METRIC_NAMES ('latency',
 * 'jitter', 'loss', 'mos').
 *
 * Uses the DEDICATED `lqm_point_metrics` endpoint. `sys_point_metrics`
 * is a different endpoint for CPU/Memory/Disk system metrics and its
 * schema rejects `filter.wan_interfaces` — that was the bug that led
 * to the endpoint switch.
 *
 * Filter shape verified against live 400s on this tenant + the
 * pan.dev LIVEcommunity #1235108 working example:
 *   - `filter.site` — ARRAY (opposite of sys_point_metrics, which
 *                    wants a string). Live 400 was
 *                    "$.filter.site: string found, array expected".
 *   - `filter.path` — array of waninterface ids. Yes, the key is
 *                    "path" — NOT `wan_interfaces` (rejected as
 *                    "not defined in the schema" on this tenant),
 *                    NOT `waninterface` (that's the sys_point_metrics
 *                    key). Prisma's LQM data model treats each
 *                    circuit as a "path".
 *
 * Missing `waninterfaceIds` returns null (with a log line) rather
 * than firing a doomed request that would come back empty.
 *
 * @param {string} siteId
 * @param {string[]} waninterfaceIds  one or more WAN interface ids
 * @param {'latency'|'jitter'|'loss'|'mos'} metricKey
 * @param {number} windowMinutes      default 5
 * @returns {Promise<object|null>}
 */
export async function getLqmMetric(siteId, waninterfaceIds, metricKey, windowMinutes = 5) {
  const spec = LQM_METRIC_NAMES[metricKey];
  if (!spec) {
    throw new Error(`Unknown LQM metric key "${metricKey}" (expected: ${Object.keys(LQM_METRIC_NAMES).join(', ')})`);
  }
  if (!siteId) return null;
  if (!Array.isArray(waninterfaceIds) || waninterfaceIds.length === 0) {
    logger('paloalto:metrics', `getLqmMetric(${metricKey}): no waninterfaceIds — skipping`, 'debug');
    return null;
  }

  try {
    const res = await paloAltoAxios.post(monitorPath('lqm_point_metrics'), {
      // NOTE: no `end_time` — the observed tenant's lqm_point_metrics
      // schema rejects it with 400 "$.end_time: is not defined in the
      // schema and the schema does not allow additional properties".
      // The endpoint interprets the window as [start_time, now).
      start_time: windowStart(windowMinutes),
      interval: pickInterval(windowMinutes),
      metrics: [{
        name: spec.name,
        statistics: ['average'],
        unit: spec.unit,
      }],
      view: {},
      filter: {
        site: [String(siteId)],
        path: waninterfaceIds,
      },
    });
    return res.data || null;
  } catch (err) {
    logMetricFailure(`getLqmMetric(${siteId}, ${metricKey})`, err);
    return null;
  }
}

// ──────────────────────────────────────────────
// Per-application "Application Path Details" metrics (v2.6 API)
// ──────────────────────────────────────────────
//
// These are what Prisma's Application Path Details dashboard renders:
// real audio/video traffic quality per app (rtp-base,
// Webex_Calling_RTP, MS_Teams_RTP, etc.) — measured on ACTUAL user
// packets via DPI, not on synthetic LQM probes across the underlying
// link. For voice diagnostics this is
// the more meaningful signal — link probes can pass while real RTP
// experiences packet loss spikes and MOS dips during flap events
// that get averaged out of the link probe view.
//
// Registry entries were confirmed via HAR captures 2026-07-09 against
// a live tenant (site CG00127) for both `rtp-base` (id 15932000365560116)
// and `Webex_Calling_RTP` (id 1708539371717015196). The metric names,
// units, and filter shapes are identical across voice apps — the only
// per-app knob is filter.app, so the check code is app-agnostic. The
// winning shapes are shown per-metric in the table below.
//
// Key filter-shape quirks:
//   - `filter.direction` is REQUIRED as `"Ingress"` for audio-quality
//     metrics (loss/jitter/MOS are what you RECEIVE). Bandwidth is
//     bidirectional aggregate and does NOT take a direction.
//   - `filter.path_type` is REQUIRED for AppPerf* metrics (loss,
//     jitter, bandwidth) but NOT for AppAudioMos.
//   - `filter.app` uses the numeric app id (resolvable via
//     `POST /sdwan/v2.5/api/appdefs/query`), NOT the display name.
//
// Response shape is IDENTICAL to v2.6 healthscore
// (metrics[].series[].data[].datapoints[{time, value}]) so downstream
// parsing can reuse the same helper.

const ALL_PATH_TYPES = Object.freeze(
  ['DirectInternet', 'VPN', 'PrivateWAN', 'PrivateVPN', 'ServiceLink'],
);

// eslint-disable-next-line no-restricted-syntax -- frozen shared registry.
export const APP_METRIC_NAMES = Object.freeze({
  mos: {
    name: 'AppAudioMos',
    unit: 'count',
    direction: 'Ingress',
    includePathType: false,
    // Lower is worse for MOS: 5=excellent, 4=good, 3.5=acceptable,
    // <3=impaired, <2=unintelligible. Grade against worst-window
    // rather than average — a 24h avg smooths over the flap events
    // that actually degrade calls.
    lowIsBad: true,
  },
  loss: {
    name: 'AppPerfUDPAudioPacketLoss',
    unit: 'percentage',
    direction: 'Ingress',
    includePathType: true,
    lowIsBad: false,
  },
  jitter: {
    name: 'AppPerfUDPAudioJitter',
    unit: 'milliseconds',
    direction: 'Ingress',
    includePathType: true,
    lowIsBad: false,
  },
  bandwidth: {
    name: 'AppPerfUDPAudioBandwidth',
    unit: 'Mbps',
    direction: null,
    includePathType: true,
    lowIsBad: null,  // bandwidth isn't a quality metric — used for context only
  },
});

// v2.6 monitor/metrics path (SASE unified prefix vs. legacy).
function appMetricsPath() {
  return isSase()
    ? '/sdwan/monitor/v2.6/api/monitor/metrics'
    : '/v2.6/api/monitor/metrics';
}

/**
 * Fetch a single per-app metric time series for a site.
 *
 * Returns the raw Prisma response body (with metrics[].series[].data
 * [].datapoints[] intact) or null on failure. The datapoints array is
 * usually 24h × 5min = 288 points; the caller is responsible for
 * client-side aggregation (avg / min / max / p95) because for voice
 * quality the WORST window matters more than the average.
 *
 * @param {string} siteId
 * @param {string} appId               Prisma numeric app id (NOT display name)
 * @param {'mos'|'loss'|'jitter'|'bandwidth'} metricKey
 * @param {number} windowMinutes       default 1440 (24h) — matches the
 *                                     shipping default for WAN checks
 * @returns {Promise<object|null>}
 */
export async function getAppMetric(siteId, appId, metricKey, windowOrOpts = 1440) {
  const spec = APP_METRIC_NAMES[metricKey];
  if (!spec) {
    throw new Error(
      `Unknown app metric key "${metricKey}" ` +
      `(expected: ${Object.keys(APP_METRIC_NAMES).join(', ')})`,
    );
  }
  if (!siteId || !appId) {
    logger('paloalto:metrics',
      `getAppMetric(${metricKey}): missing siteId or appId — skipping`, 'debug');
    return null;
  }

  let startTime;
  let endTime;
  let windowMinutes;
  if (
    windowOrOpts
    && typeof windowOrOpts === 'object'
    && windowOrOpts.startTime
    && windowOrOpts.endTime
  ) {
    startTime = windowOrOpts.startTime;
    endTime = windowOrOpts.endTime;
    windowMinutes = Math.max(
      1,
      Math.round((new Date(endTime).getTime() - new Date(startTime).getTime()) / 60_000),
    );
  } else {
    windowMinutes = typeof windowOrOpts === 'number' ? windowOrOpts : 1440;
    startTime = windowStart(windowMinutes);
    endTime = nowIso();
  }

  const filter = {
    site: [String(siteId)],
    app:  [String(appId)],
  };
  if (spec.includePathType) filter.path_type = [...ALL_PATH_TYPES];
  if (spec.direction)       filter.direction = spec.direction;

  try {
    const res = await paloAltoAxios.post(appMetricsPath(), {
      start_time: startTime,
      end_time:   endTime,
      // NOT pickInterval — see pickAppMetricInterval doc for why:
      // app metrics need the fine-grained series or the client-side
      // worst-window aggregation is meaningless.
      interval:   pickAppMetricInterval(windowMinutes),
      metrics: [{
        name: spec.name,
        statistics: ['average'],
        unit: spec.unit,
      }],
      filter,
      view: {},
    });
    return res.data || null;
  } catch (err) {
    logMetricFailure(`getAppMetric(${siteId}, app=${appId}, ${metricKey})`, err);
    return null;
  }
}

// ──────────────────────────────────────────────
// Alarms (via the events/query endpoint)
// ──────────────────────────────────────────────

/**
 * Recent alarms for the site. Uses the SASE events endpoint
 * (`POST /sdwan/v3.7/api/events/query`) — the older
 * `/monitor/v2.0/api/monitor/alarms` path 404s on this tenant
 * ("ROUTE_NOT_FOUND_0001").
 *
 * Body shape mirrors the Prisma ServiceNow CloudBlade example
 * (pan.dev + PA integration guide): `limit` is an OBJECT with
 * `count`/`sort_on`/`sort_order`, `query` carries `site`/`type`,
 * `severity` is a top-level array, `start_time` is ISO.
 * Additionally we filter `type: ['alarm']` so we don't get
 * informational events mixed into the alarm count.
 *
 * @param {string} siteId
 * @param {number} windowMinutes  default 60
 * @returns {Promise<object|null>}
 */
export async function getAlarms(siteId, windowMinutes = 60) {
  if (!siteId) return null;

  try {
    const res = await paloAltoAxios.post(eventsQueryPath(), {
      limit: {
        count: 100,
        sort_on: 'time',
        sort_order: 'descending',
      },
      query: {
        site: [String(siteId)],
        type: ['alarm'],
      },
      severity: ['critical', 'major', 'minor'],
      start_time: windowStart(windowMinutes),
    });
    return res.data || null;
  } catch (err) {
    logMetricFailure(`getAlarms(${siteId})`, err);
    return null;
  }
}