import type { WorkOrderComment } from "@/domain/work-orders/types/work-order-detail";
import { isOwnWorkOrderComment } from "@/domain/work-orders/utils/comment-ownership";
import { extractMentionIds } from "@/domain/work-orders/utils/comment-mentions";
import type { CommentHighlight } from "@/domain/work-orders/utils/work-order-deep-link";

/**
 * Ids of the comments a notification was raised for. The feed starts a comment item at its first
 * unanswered comment and a mention item at the mentioning comment, so this is every comment by
 * someone else from that moment on, split the same way the feed splits them: comments that
 * mention the user belong to Mentions, the rest to Recent activity.
 */
// why: Board comment times arrive as UTC without a zone designator; read them as UTC, not local time.
function parseUtc(value: string): number {
  return Date.parse(/(Z|[+-]\d{2}:?\d{2})$/i.test(value) ? value : `${value}Z`);
}

export function highlightedCommentIds(
  comments: WorkOrderComment[],
  highlight: CommentHighlight | null | undefined,
  currentUserId: string | number | null | undefined,
): Set<string> {
  const ids = new Set<string>();
  const since = highlight == null ? Number.NaN : parseUtc(highlight.since);
  if (highlight == null || Number.isNaN(since) || currentUserId == null || currentUserId === "") {
    return ids;
  }
  const userId = String(currentUserId);
  for (const comment of comments) {
    const createdAt = parseUtc(comment.createdDate);
    if (Number.isNaN(createdAt) || createdAt < since || isOwnWorkOrderComment(comment, userId)) {
      continue;
    }
    // why: Board comments expose mentions two ways: an encoded `@[id:name]` token in the text, or a
    // `mentions` id array alongside plain `@Name` text. Treat either as a mention of the user.
    const mentionIds = new Set(extractMentionIds(comment.commenttext ?? ""));
    for (const id of comment.mentions ?? []) {
      mentionIds.add(String(id));
    }
    const mentionsUser = mentionIds.has(userId);
    if (mentionsUser === highlight.mentions) {
      ids.add(String(comment.id));
    }
  }
  return ids;
}