// Shared plumbing for the admin example plugin: the section nav fragment, the admin-only gate, the
// CSRF-guarded form reader, the destructive-confirm model builder, and small RouteResult helpers
// (themed not-found / capability-unavailable). Ported from the former built-in admin screens;
// everything imports the host only through the #plugin-api barrel.

import { can, CSRF_FIELD, GuardError, type NavNode, readFormBody, type RequestContext, requireSession, type RouteResult, type User } from "#plugin-api";

export const ADMIN_PERMISSION = "admin"; // role token gating the whole admin section
export const ADMIN_USERS_BASE = "/admin/users";
export const ADMIN_GROUPS_BASE = "/admin/groups";
export const ADMIN_ROLES_BASE = "/admin/roles";
export const ADMIN_CLIENTS_BASE = "/admin/clients";

export type AdminScreen = "clients" | "groups" | "roles" | "users";

// The plugin's nav fragment: the gated "Admin" header + its four screens. The host composes it into
// the one global menu, filters per user (the header's `permission` drops the whole subtree for a
// non-admin), and current-marks the active item — so there is no `current`/`open` state here.
export const ADMIN_NAV: NavNode = {
  children: [
    { href: ADMIN_USERS_BASE, icon: "i-users", id: "users", label: "Users" },
    { href: ADMIN_GROUPS_BASE, icon: "i-layers", id: "groups", label: "Groups" },
    { href: ADMIN_ROLES_BASE, icon: "i-shield", id: "roles", label: "Roles" },
    { href: ADMIN_CLIENTS_BASE, icon: "i-globe", id: "clients", label: "OAuth2 clients" },
  ],
  icon: "i-shield",
  id: "admin",
  label: "Admin",
  permission: ADMIN_PERMISSION,
};

// The admin gate: a signed-in admin only. Each route already declares `permission: "admin"`, so the
// host enforces this before the handler runs; this is defence-in-depth and what a direct unit test
// relies on. Returns the (non-null) user for the handler to thread on. GuardError → /login or 403.
export function requireAdmin(ctx: RequestContext): User {
  const user = requireSession(ctx); // anonymous → GuardError → /login (return_to kept)
  if (!can(ctx, ADMIN_PERMISSION)) throw new GuardError(403, "admin role required");
  return user;
}

// Read + CSRF-verify a mutation's form body once (double-submit via ctx.verifyCsrf); non-POST ⇒
// undefined. A POST without a valid token is refused (GuardError → 403).
export async function guardedForm(ctx: RequestContext): Promise<URLSearchParams | undefined> {
  if ((ctx.req.method ?? "GET").toUpperCase() !== "POST") return undefined;
  const form = await readFormBody(ctx.req);
  if (!ctx.verifyCsrf(form.get(CSRF_FIELD))) throw new GuardError(403, "invalid CSRF token");
  return form;
}

// A themed "not found" (bad id/name in the path) rendered in the admin shell — 404, never a 500.
export function notFound(ctx: RequestContext): RouteResult {
  return { data: { chrome: ctx.chrome, message: "That item doesn't exist.", title: "Not found" }, status: 404, view: "notice" };
}

// A capability the plugin needs isn't on ctx.system (Ory not wired). Login already requires these in
// a real deployment, so this is the honest 503 fallback for a misconfigured host, not a crash.
export function unavailable(ctx: RequestContext, what: string): RouteResult {
  return { data: { chrome: ctx.chrome, message: `${what} is not configured on this deployment.`, title: "Admin unavailable" }, status: 503, view: "notice" };
}

// Model for the shared destructive-confirm page (views/confirm.ejs). The view reads the shell fields
// (brand/csrf/theme/user/nav) from ctx.chrome; this carries only the page body + title/breadcrumbs.
export function buildConfirmModel(opts: {
  breadcrumbs: { href?: string; label: string }[];
  cancelHref: string;
  confirmAction: string;
  confirmLabel: string;
  message: string;
  title: string;
}) {
  return {
    breadcrumbs: opts.breadcrumbs,
    cancelHref: opts.cancelHref,
    confirm: { action: opts.confirmAction, label: opts.confirmLabel },
    message: opts.message,
    title: opts.title,
  };
}