// Auteur : Simon-Pierre Boucher — contact@spboucher.ai
// -----------------------------------------------------------------------------
// Groupe KA — kaid.ts : client KA ID v2 (personnalisation) pour les apps Next.
// SOURCE CANONIQUE : ka-ui.git/kaid/kaid.ts — copié dans src/lib/kaid.ts des
// apps TypeScript (vrai-prix, valoplex, trouve-ka). Ne pas diverger.
//
// Équivalent TS de kaid.py : track() (journal, fire-and-forget) et
// fetchPrefs() (profil appris, cache 90 s, fail-open). Appels SERVEUR
// uniquement (route handlers) — le secret SSO ne va jamais au navigateur.
//   sig = HMAC-SHA256(KA_SSO_SECRET, `${clientId}.${kaId}.${ts}`) en hex.
// Aucune dépendance : node:crypto + fetch natif.
// -----------------------------------------------------------------------------
import { createHmac } from "node:crypto";

export type KaidEvent = {
  type: string;
  entity_type?: string;
  entity_id?: string;
  query?: string;
  filters?: Record<string, unknown>;
  position?: number;
  features?: Record<string, unknown>;
  dwell_ms?: number;
  session_id?: string;
};

export type KaidPrefs = {
  ok: boolean;
  personalization: boolean;
  profile: {
    app: {
      n: number;
      dims: Record<string, { values: Record<string, number>; conf: number }>;
      ranges: Record<string, { p25: number; p50: number; p75: number; n: number }>;
    } | null;
    global: { location: { values: Record<string, number>; conf: number } };
  } | null;
  hidden: string[];
} | null;

const TIMEOUT_MS = 5_000;
const PREFS_TTL_MS = 90_000;
const prefsCache = new Map<string, { t: number; data: KaidPrefs }>();

function hubUrl(): string {
  return (process.env.KA_HUB_URL ?? "https://www.groupe-ka.com").replace(/\/+$/, "");
}

function signedParams(clientId: string, kaId: string): URLSearchParams | null {
  const secret = process.env.KA_SSO_SECRET;
  if (!secret || !kaId.startsWith("ka-")) return null;
  const ts = String(Math.floor(Date.now() / 1000));
  const sig = createHmac("sha256", secret)
    .update(`${clientId}.${kaId}.${ts}`)
    .digest("hex");
  return new URLSearchParams({ client_id: clientId, ka_id: kaId, ts, sig });
}

/** Journalise des événements au hub — fire-and-forget, jamais bloquant. */
export function track(
  clientId: string,
  kaId: string | null | undefined,
  events: KaidEvent[],
): void {
  if (!kaId || !events.length) return;
  const p = signedParams(clientId, kaId);
  if (!p) return;
  const body = JSON.stringify({
    ...Object.fromEntries(p),
    events: events.slice(0, 20),
  });
  fetch(`${hubUrl()}/api/sso/events`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body,
    signal: AbortSignal.timeout(TIMEOUT_MS),
  }).catch(() => {});
}

/** Profil de personnalisation (cache 90 s) — null si indisponible (fail-open). */
export async function fetchPrefs(
  clientId: string,
  kaId: string | null | undefined,
): Promise<KaidPrefs> {
  if (!kaId) return null;
  const hit = prefsCache.get(kaId);
  if (hit && Date.now() - hit.t < PREFS_TTL_MS) return hit.data;
  const p = signedParams(clientId, kaId);
  if (!p) return null;
  let data: KaidPrefs = null;
  try {
    const r = await fetch(`${hubUrl()}/api/sso/prefs?${p}`, {
      signal: AbortSignal.timeout(TIMEOUT_MS),
    });
    if (r.ok) data = (await r.json()) as KaidPrefs;
  } catch {
    data = null;
  }
  prefsCache.set(kaId, { t: Date.now(), data });
  if (prefsCache.size > 500)
    for (const k of [...prefsCache.keys()].slice(0, 100)) prefsCache.delete(k);
  return data;
}

/** Affinité [−1,1] d'une valeur dans une dimension du profil (0 si inconnue). */
export function affinity(
  prefs: KaidPrefs,
  dim: string,
  value: string | null | undefined,
): number {
  const d = prefs?.profile?.app?.dims?.[dim];
  if (!d || !value) return 0;
  return d.values[value.trim().toLowerCase()] ?? 0;
}

/** Affinité de localisation transversale (tous univers confondus). */
export function globalLocationAffinity(
  prefs: KaidPrefs,
  value: string | null | undefined,
): number {
  const loc = prefs?.profile?.global?.location;
  if (!loc || !value) return 0;
  return (loc.values[value.trim().toLowerCase()] ?? 0) * (loc.conf || 0.3);
}