/**
 * Turns the rows the comment service reads from `comments` into the {@link
 * Comment} the comment routes send.
 *
 * @module
 */

import type { SQLOutputValue } from "node:sqlite";
import type { Comment } from "../../shared/comment.ts";

/**
 * Returned by the comment service's `SELECT`s on `comments`, joined with
 * `users` for the `author_` columns.
 */
export interface CommentRow {
  id: string;
  dump_id: string;
  user_id: string;
  /** It is null on a top-level comment. */
  parent_id: string | null;
  body: string;
  created_at: string;
  updated_at: string | null;
  /**
   * 1 once deleted. The body is emptied but the row stays, so its replies keep
   * their place in the thread.
   */
  deleted: number;
  like_count: number;
  author_username: string;
  author_avatar_mime: string | null;
  [key: string]: SQLOutputValue;
}

/** Checks whether a row `node:sqlite` returned is a {@link CommentRow}. */
export function isCommentRow(
  obj: unknown,
): obj is CommentRow {
  return !!obj && typeof obj === "object" &&
    "id" in obj && typeof obj.id === "string" &&
    "dump_id" in obj && typeof obj.dump_id === "string" &&
    "user_id" in obj && typeof obj.user_id === "string" &&
    "parent_id" in obj &&
    (typeof obj.parent_id === "string" || obj.parent_id === null) &&
    "body" in obj && typeof obj.body === "string" &&
    "created_at" in obj && typeof obj.created_at === "string" &&
    "updated_at" in obj &&
    (typeof obj.updated_at === "string" || obj.updated_at === null) &&
    "deleted" in obj && typeof obj.deleted === "number" &&
    "like_count" in obj && typeof obj.like_count === "number" &&
    "author_username" in obj && typeof obj.author_username === "string" &&
    "author_avatar_mime" in obj &&
    (typeof obj.author_avatar_mime === "string" ||
      obj.author_avatar_mime === null);
}

/**
 * Converts `row` to the {@link Comment} the comment routes send and the
 * WebSocket broadcasts.
 */
export function commentRowToApi(row: CommentRow): Comment {
  return {
    id: row.id,
    dumpId: row.dump_id,
    userId: row.user_id,
    parentId: row.parent_id ?? undefined,
    body: row.body,
    createdAt: new Date(row.created_at),
    updatedAt: row.updated_at ? new Date(row.updated_at) : undefined,
    deleted: Boolean(row.deleted),
    likeCount: row.like_count,
    authorUsername: row.author_username,
    authorAvatarMime: row.author_avatar_mime ?? undefined,
  };
}