/**
 * Consentement aux témoins (cookies) — Loi 25 (Québec) / RGPD :
 * refus par défaut pour tout ce qui n'est pas strictement nécessaire,
 * choix granulaire, révocable à tout moment, conservé 180 jours.
 *
 * Le site ne pose aujourd'hui AUCUN témoin non nécessaire : ce module est la
 * porte d'entrée obligatoire pour tout futur outil d'analyse ou de marketing
 * (`hasConsent("analytics")` avant de charger un script).
 */

export const CONSENT_COOKIE = "phi_consent";
export const CONSENT_VERSION = 1;
export const CONSENT_MAX_AGE_S = 180 * 24 * 60 * 60;
export const CONSENT_EVENT = "phi-consent-change";
export const CONSENT_OPEN_EVENT = "phi-consent-open";

export const OPTIONAL_CATEGORIES = ["analytics", "marketing"] as const;
export type OptionalCategory = (typeof OPTIONAL_CATEGORIES)[number];
export type Category = "necessary" | OptionalCategory;

export type Consent = {
  version: number;
  date: string; // ISO
  necessary: true;
  analytics: boolean;
  marketing: boolean;
};

export function allRejected(): Consent {
  return { version: CONSENT_VERSION, date: new Date().toISOString(), necessary: true, analytics: false, marketing: false };
}

export function allAccepted(): Consent {
  return { version: CONSENT_VERSION, date: new Date().toISOString(), necessary: true, analytics: true, marketing: true };
}

export function parseConsent(raw: string | null | undefined): Consent | null {
  if (!raw) return null;
  try {
    const v = JSON.parse(decodeURIComponent(raw)) as Partial<Consent>;
    if (v.version !== CONSENT_VERSION) return null; // nouvelle version = redemander
    if (typeof v.analytics !== "boolean" || typeof v.marketing !== "boolean") return null;
    return {
      version: CONSENT_VERSION,
      date: typeof v.date === "string" ? v.date : new Date(0).toISOString(),
      necessary: true,
      analytics: v.analytics,
      marketing: v.marketing,
    };
  } catch {
    return null;
  }
}

export function serializeConsent(c: Consent): string {
  return encodeURIComponent(JSON.stringify(c));
}

export function readConsentCookie(cookieHeader: string): Consent | null {
  const m = cookieHeader.match(new RegExp(`(?:^|;\\s*)${CONSENT_COOKIE}=([^;]*)`));
  return parseConsent(m?.[1]);
}

export function hasConsent(consent: Consent | null, category: Category): boolean {
  if (category === "necessary") return true;
  return consent?.[category] === true;
}