/**
 * The permission families TREK enforces OUTSIDE the ctx object — and the single
 * PermissionDenied both the dev server and the mock host throw.
 *
 * ctx methods are gated at call time (an ungranted ctx.trips.getById throws). But a
 * hook, an event subscription and a job are gated BEFORE the plugin is ever reached:
 * the supervisor simply never selects an ungranted plugin as a provider, never
 * delivers it an event, and never schedules its jobs. That failure is SILENT in
 * production — the plugin installs, activates, and then does nothing at all — so dev
 * and the mock driver must be the place it becomes loud.
 */

/** Thrown by the dev server and the mock host for any ungranted capability. */
export class PermissionDenied extends Error {}

/**
 * hooks.<key> -> the permission that must ALSO be granted for TREK to ever call it, plus
 * the three capability gates that are not hooks.* keys.
 *
 * These are GENERATED from the host's single source, server/src/nest/plugins/protocol/
 * envelope.ts, by server/scripts/gen-plugin-facts.ts. They used to be a hand-kept copy
 * guarded by a regex scrape of plugin-supervisor.ts in test/permissions-parity.test.ts -
 * which only ran from prepublishOnly, so drift would have surfaced as a broken release.
 *
 * The re-exported types stay WIDE (Readonly<Record<string, string>>), exactly as before:
 * grantGaps below indexes HOOK_PERMISSION with a plain string, and this package compiles
 * under "strict": true.
 */
export {
  HOOK_PERMISSION,
  USER_DATA_PERMISSION,
  EVENTS_PERMISSION,
  JOBS_PERMISSION,
} from './generated/host-facts.js';
import {
  HOOK_PERMISSION, USER_DATA_PERMISSION, EVENTS_PERMISSION, JOBS_PERMISSION,
  HTTP_OUTBOUND_PREFIX as HTTP_OUTBOUND,
} from './generated/host-facts.js';

/** The structural shape of a loaded plugin that grantGaps needs. */
export interface PluginEntryPoints {
  jobs?: unknown[];
  scheduled?: unknown;
  events?: unknown[];
  deleteUserData?: unknown;
  exportUserData?: unknown;
  hooks?: Record<string, unknown>;
}

/** An entry point the plugin implements but has no permission to actually run. */
export interface GrantGap {
  /** What the plugin implements, e.g. `hooks.warningProvider` or `jobs`. */
  entryPoint: string;
  /** The permission the manifest is missing. */
  permission: string;
  /** What TREK does instead — always a silent no-op, hence the warning. */
  consequence: string;
}

/**
 * Every entry point the plugin implements without the permission that makes TREK
 * call it. Pure, so both the dev banner and the tests can use it.
 *
 * The consequence is worth spelling out to the author: production does NOT throw
 * here, it just never invokes them — "my plugin does nothing and logs nothing" is
 * exactly the bug this catches.
 */
export function grantGaps(plugin: PluginEntryPoints, grants: ReadonlySet<string>): GrantGap[] {
  const gaps: GrantGap[] = [];
  const gap = (entryPoint: string, permission: string, noun: string) => {
    if (!grants.has(permission)) gaps.push({ entryPoint, permission, consequence: `TREK will never ${noun}` });
  };

  for (const key of Object.keys(plugin.hooks ?? {})) {
    const perm = HOOK_PERMISSION[key];
    // An unknown hooks.* key is the plugin's business (the host ignores it), not a gap.
    if (perm && plugin.hooks?.[key]) gap(`hooks.${key}`, perm, `call this hook`);
  }
  if (plugin.jobs?.length) gap('jobs', JOBS_PERMISSION, 'schedule your jobs');
  if (typeof plugin.scheduled === 'function') gap('scheduled', JOBS_PERMISSION, 'let you arm a timer (ctx.scheduler is denied)');
  if (plugin.events?.length) gap('events', EVENTS_PERMISSION, 'deliver you any event');
  if (typeof plugin.deleteUserData === 'function') gap('deleteUserData', USER_DATA_PERMISSION, 'call your GDPR erasure handler');
  if (typeof plugin.exportUserData === 'function') gap('exportUserData', USER_DATA_PERMISSION, 'call your GDPR export handler');
  return gaps;
}

/**
 * The hosts a plugin may actually reach. TREK builds its runtime network allowlist
 * from the `http:outbound:<host>` PERMISSIONS — the manifest's `egress[]` array is
 * the consent-screen declaration and is never read at runtime. A bare `http:outbound`
 * with no host suffix therefore reaches nothing.
 */
export function grantedHosts(grants: Iterable<string>): string[] {
  return [...grants]
    .filter((p) => p.startsWith(HTTP_OUTBOUND))
    .map((p) => p.slice(HTTP_OUTBOUND.length))
    .filter(Boolean); // a bare `http:outbound:` names no host
}