import { z } from 'zod';

/**
 * Types and schemas for the short-lived collaboration tokens (issue #34,
 * ADR 0003/0007). These are browser-safe (no Node built-ins) so the web app
 * can import them from the package barrel. The signing/verifying helpers live
 * in `./token-crypto` (Node `crypto`) and are imported only by the api and the
 * collab server.
 */

export const collabTokenModeSchema = z.enum(['rw', 'ro']);
export type CollabTokenMode = z.infer<typeof collabTokenModeSchema>;

/**
 * PostgreSQL `LISTEN/NOTIFY` channel over which the api announces that the
 * access situation of a pond changed (issue #39, permissions.md §Performance).
 * The notification payload is the pond id. The api emits it whenever a
 * permission-relevant change happens (interim: pond soft-delete; from M5 on:
 * grant changes, #53); the collab server listens and re-validates every open
 * connection to that pond's pages by closing them so clients reconnect and
 * re-acquire a token reflecting the current access.
 */
export const POND_ACCESS_CHANGED_CHANNEL = 'pond_access_changed';

/**
 * PostgreSQL `NOTIFY` channel over which the api asks the collab server to
 * restore a page to an earlier version (issue #42, ADR 0013). The api does the
 * permission check, then emits this; the collab server owns the live document,
 * so it snapshots the current state (a `PRE_RESTORE` version) and applies the
 * restored content as a normal edit through the document, converging every open
 * client. Payload is a JSON {@link PageRestoreRequest}.
 */
export const PAGE_RESTORE_CHANNEL = 'page_restore';

/**
 * PostgreSQL `NOTIFY` channel over which the collab server announces that it
 * wrote an automatic version snapshot (issue #94): the api listens and fans
 * the change out to watchers as notifications — permission-checked there,
 * where the resolution lives. Payload is a JSON {@link PageVersionCreatedEvent}.
 */
export const PAGE_VERSION_CREATED_CHANNEL = 'page_version_created';

/** JSON payload carried on {@link PAGE_VERSION_CREATED_CHANNEL}. */
export interface PageVersionCreatedEvent {
  pageId: string;
  /** Everyone who contributed to the snapshot — all excluded from fan-out. */
  contributorIds: string[];
}

/** JSON payload carried on {@link PAGE_RESTORE_CHANNEL}. */
export interface PageRestoreRequest {
  pageId: string;
  versionId: string;
  /** The user who triggered the restore (recorded on the pre-restore snapshot). */
  userId: string;
}

/** The application claims carried by a collaboration token. */
export const collabTokenClaimsSchema = z.object({
  // `null` for an anonymous visitor holding a public read-only token (issue
  // #53); a user id for a signed-in participant (used for presence/versioning).
  userId: z.string().min(1).nullable(),
  pageId: z.string().min(1),
  mode: collabTokenModeSchema,
});
export type CollabTokenClaims = z.infer<typeof collabTokenClaimsSchema>;

/** Response of `GET /pages/:id/collab-token`. */
export interface CollabTokenResponse {
  token: string;
  mode: CollabTokenMode;
  expiresInSeconds: number;
}

export type CollabTokenVerification =
  | { valid: true; claims: CollabTokenClaims }
  | {
      valid: false;
      reason: 'malformed' | 'bad_algorithm' | 'bad_signature' | 'expired' | 'invalid_claims';
    };