/**
 * @factory/shared/realtime/comment-events — the comment stream-event →
 * `comment.event` frame-kind mapping (TASK-0094 R1).
 *
 * Two layers, one emission (recorded in the task file):
 *   - the PUBLIC stream events on `factory:events` (the Phase-1 catalog:
 *     `comment.created` / `comment.resolved` — Phase-13 webhooks listen here);
 *   - the ROOM-INTERNAL `comment.event` frame, whose `kind` set is
 *     `created | replied | resolved | reopened | reacted | deleted` (the
 *     comment panel's full reactivity).
 *
 * The API's CommentModule emits ONE event per operation; this mapping
 * derives the frame kind from the event name + payload:
 *   - `comment.created`    → `replied` when the payload carries a
 *     `replyId` (a reply is a comment with a parent — the API emits
 *     `comment.created` for replies too, the catalog shape), else `created`.
 *   - `comment.reopened`   → `reopened`   (additive internal event)
 *   - `comment.reaction`   → `reacted`    (additive internal event)
 *   - `comment.deleted`    → `deleted`    (additive internal event)
 *   - `comment.resolved`   → `resolved`   (catalog event)
 *
 * The realtime server (the `comment-notification-source`) is the ONLY
 * consumer of this table; both the API (emitter) and the realtime app
 * (mapper) import it from here so the two layers cannot drift.
 */

import type { DomainEvent } from "../events.js";

/** The `comment.event` frame kinds (the frame schema's enum — lockstep). */
export const COMMENT_EVENT_KINDS = [
  "created",
  "replied",
  "resolved",
  "reopened",
  "reacted",
  "deleted",
] as const;
export type CommentEventKind = (typeof COMMENT_EVENT_KINDS)[number];

/** The stream event names that map to a comment frame (single source). */
export const COMMENT_EVENT_STREAM_NAMES = [
  "comment.created",
  "comment.resolved",
  "comment.reopened",
  "comment.reaction",
  "comment.deleted",
] as const;
export type CommentEventStreamName = (typeof COMMENT_EVENT_STREAM_NAMES)[number];

/**
 * Derive the `comment.event` frame kind from a stream event envelope.
 * `null` when the event does not map to a comment frame (any other event
 * name, or a malformed payload).
 *
 * The reply case is payload-driven: the API emits `comment.created` for
 * BOTH a new thread and a reply (a reply = a comment with a parent); the
 * reply payload carries `replyId` (the reply row id) + `commentId` (the
 * parent thread id). A `comment.created` WITHOUT a `replyId` is a new
 * thread → `created`.
 */
export function commentEventKindForEvent(event: DomainEvent): CommentEventKind | null {
  const payload = event.payload as Record<string, unknown> | null | undefined;
  switch (event.name) {
    case "comment.created": {
      // A reply is a `comment.created` whose payload carries a `replyId`.
      return payload && typeof payload.replyId === "string" ? "replied" : "created";
    }
    case "comment.resolved":
      return "resolved";
    case "comment.reopened":
      return "reopened";
    case "comment.reaction":
      return "reacted";
    case "comment.deleted":
      return "deleted";
    default:
      return null;
  }
}