export const POINT_STANDARDS_PATH = '/points/standards';

export const POINT_STANDARD_PAGE_SIZE_OPTIONS = [10, 30, 50] as const;
export type PointStandardPageSize =
  (typeof POINT_STANDARD_PAGE_SIZE_OPTIONS)[number];

export const DEFAULT_POINT_STANDARD_PAGE_SIZE: PointStandardPageSize = 10;
const DEFAULT_PAGE = 1;
const MAX_KEYWORD_LENGTH = 100;

/** 검색어 하나가 이벤트와 이벤트 설명을 함께 훑는다(기획 PTS10100001 ①). */
export type PointStandardQuery = {
  keyword: string;
  page: number;
  pageSize: PointStandardPageSize;
};

type RawSearchParams = Record<string, string | string[] | undefined>;

function readParam(params: RawSearchParams, key: string): string | undefined {
  const value = params[key];
  return Array.isArray(value) ? value[0] : value;
}

function isPointStandardPageSize(value: number): value is PointStandardPageSize {
  return (POINT_STANDARD_PAGE_SIZE_OPTIONS as readonly number[]).includes(value);
}

export function parsePointStandardQuery(
  searchParams: RawSearchParams
): PointStandardQuery {
  const keywordRaw = readParam(searchParams, 'keyword');
  const pageRaw = Number(readParam(searchParams, 'page'));
  const pageSizeRaw = Number(readParam(searchParams, 'pageSize'));

  return {
    keyword: (keywordRaw ?? '').trim().slice(0, MAX_KEYWORD_LENGTH),
    page: Number.isInteger(pageRaw) && pageRaw > 0 ? pageRaw : DEFAULT_PAGE,
    pageSize: isPointStandardPageSize(pageSizeRaw)
      ? pageSizeRaw
      : DEFAULT_POINT_STANDARD_PAGE_SIZE,
  };
}

export function buildPointStandardHref(
  query: PointStandardQuery,
  overrides: Partial<PointStandardQuery> = {}
): string {
  const merged = { ...query, ...overrides };
  const params = new URLSearchParams();

  if (merged.keyword) {
    params.set('keyword', merged.keyword);
  }
  if (merged.pageSize !== DEFAULT_POINT_STANDARD_PAGE_SIZE) {
    params.set('pageSize', String(merged.pageSize));
  }
  if (merged.page !== DEFAULT_PAGE) {
    params.set('page', String(merged.page));
  }

  const queryString = params.toString();
  return queryString
    ? `${POINT_STANDARDS_PATH}?${queryString}`
    : POINT_STANDARDS_PATH;
}