/**
 * The `comments` table: its row type, its guard, and its mapper to the API's
 * {@link Comment}.
 *
 * @module
 */

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

/** A row of the `comments` table, joined with its author. */
export interface CommentRow {
  /** The comment's id. */
  id: string;
  /** The id of the dump it is posted under. */
  dump_id: string;
  /** The author's id. */
  user_id: string;
  /** The id of the comment it replies to; null at the top level. */
  parent_id: string | null;
  /** The comment, in Markdown. */
  body: string;
  /** When the comment was posted. */
  created_at: string;
  /** When the comment was last edited, if ever. */
  updated_at: string | null;
  /**
   * 1 once deleted: the body is emptied but the row stays, so its replies
   * keep their place.
   */
  deleted: number;
  /** How many users like the comment. */
  like_count: number;
  /** The author's name (joined). */
  author_username: string;
  /** The author's avatar type, null without one (joined). */
  author_avatar_mime: string | null;
  /** Any other column the query selects. */
  [key: string]: SQLOutputValue;
}

/** Checks whether `obj` 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 a row to the API's {@link Comment}. */
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,
  };
}