/* ═══════════════════════════════════════════════════════════════
   ROLES — src/lib/roles.ts

   The same ladder as server/src/auth.js, and it has to stay the
   same ladder. This copy exists to decide what to draw; the
   server's copy decides what's allowed. If they ever disagree the
   worst case is a button that 403s, which is the right way round
   for them to fail.

   Components should ask canDelete(user), not
   user.role === "admin". The second form is what silently locked
   superadmins out of saving when the third role went in: an
   equality check against a ladder is a bug waiting for the next
   role to be added, and there's now a fourth.
   ═══════════════════════════════════════════════════════════════ */

export const ROLES = ["viewer", "editor", "admin", "superadmin"] as const;

export type Role = (typeof ROLES)[number];

export const ROLE_RANK: Record<Role, number> = {
  viewer: 1,
  editor: 2,
  admin: 3,
  superadmin: 4,
};

export const ROLE_LABELS: Record<Role, string> = {
  viewer: "Viewer",
  editor: "Editor",
  admin: "Admin",
  superadmin: "Superadmin",
};

/* Each line is what that role adds to the one above it in the
   list. Read top to bottom, they describe the whole ladder. */
export const ROLE_NOTES: Record<Role, string> = {
  viewer: "Can read everything in the CMS and change nothing.",
  editor: "Can create and update records. Can't delete anything.",
  admin: "Can delete records, including feedback.",
  superadmin: "Can manage accounts, roles and sessions.",
};

type MaybeUser = { role?: string | null } | null | undefined;

/* Minimum, not equality: a superadmin passes atLeast(user, "editor"). */
export function atLeast(user: MaybeUser, role: Role): boolean {
  const have = ROLE_RANK[(user?.role ?? "") as Role] ?? 0;
  return have >= ROLE_RANK[role];
}

/* Named for the capability rather than the rank, so call sites
   read as intent and a future reshuffle of the ladder is one edit
   here rather than a search for every comparison. */
export const canWrite = (user: MaybeUser) => atLeast(user, "editor");
export const canDelete = (user: MaybeUser) => atLeast(user, "admin");
export const isSuper = (user: MaybeUser) => atLeast(user, "superadmin");