export const POINT_ACCOUNTS_PATH = '/points/accumulated';

export type PointAccountSearchField = 'loginId' | 'studentName';

export const POINT_ACCOUNT_SEARCH_FIELD_OPTIONS: ReadonlyArray<{
  value: PointAccountSearchField;
  label: string;
}> = [
  { value: 'loginId', label: '아이디' },
  { value: 'studentName', label: '이름' },
];

/** 필터 셀렉트의 "전체" 값 — URL에서는 생략되고 화면에서는 이 값이 선택된다. */
export const FILTER_ALL = 'all';

export const GRADE_OPTIONS = [1, 2, 3] as const;
export const CLASS_OPTIONS = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] as const;
export const NUMBER_OPTIONS = Array.from({ length: 30 }, (_, index) => index + 1);

/** 상세내역 팝업 안의 페이지 크기(기획 PTS10300001). */
export const POINT_HISTORY_PAGE_SIZE = 5;

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

export const DEFAULT_POINT_ACCOUNT_SEARCH_FIELD: PointAccountSearchField =
  'loginId';
export const DEFAULT_POINT_ACCOUNT_PAGE_SIZE: PointAccountPageSize = 10;
const DEFAULT_PAGE = 1;
const MAX_KEYWORD_LENGTH = 100;
const MAX_SCHOOL_NAME_LENGTH = 100;

export type PointAccountQuery = {
  schoolName: string;
  grade: number | null;
  classNo: number | null;
  studentNo: number | null;
  searchField: PointAccountSearchField;
  keyword: string;
  page: number;
  pageSize: PointAccountPageSize;
};

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 readNumberIn(
  params: RawSearchParams,
  key: string,
  allowed: readonly number[]
): number | null {
  const value = Number(readParam(params, key));
  return Number.isInteger(value) && allowed.includes(value) ? value : null;
}

function isPointAccountSearchField(
  value: string | undefined
): value is PointAccountSearchField {
  return (
    value !== undefined &&
    POINT_ACCOUNT_SEARCH_FIELD_OPTIONS.some((option) => option.value === value)
  );
}

function isPointAccountPageSize(value: number): value is PointAccountPageSize {
  return (POINT_ACCOUNT_PAGE_SIZE_OPTIONS as readonly number[]).includes(value);
}

export function parsePointAccountQuery(
  searchParams: RawSearchParams
): PointAccountQuery {
  const searchFieldRaw = readParam(searchParams, 'searchField');
  const keywordRaw = readParam(searchParams, 'keyword');
  const schoolNameRaw = readParam(searchParams, 'schoolName');
  const pageRaw = Number(readParam(searchParams, 'page'));
  const pageSizeRaw = Number(readParam(searchParams, 'pageSize'));

  return {
    schoolName: (schoolNameRaw ?? '').trim().slice(0, MAX_SCHOOL_NAME_LENGTH),
    grade: readNumberIn(searchParams, 'grade', GRADE_OPTIONS),
    classNo: readNumberIn(searchParams, 'classNo', CLASS_OPTIONS),
    studentNo: readNumberIn(searchParams, 'studentNo', NUMBER_OPTIONS),
    searchField: isPointAccountSearchField(searchFieldRaw)
      ? searchFieldRaw
      : DEFAULT_POINT_ACCOUNT_SEARCH_FIELD,
    keyword: (keywordRaw ?? '').trim().slice(0, MAX_KEYWORD_LENGTH),
    page: Number.isInteger(pageRaw) && pageRaw > 0 ? pageRaw : DEFAULT_PAGE,
    pageSize: isPointAccountPageSize(pageSizeRaw)
      ? pageSizeRaw
      : DEFAULT_POINT_ACCOUNT_PAGE_SIZE,
  };
}

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

  if (merged.schoolName) {
    params.set('schoolName', merged.schoolName);
  }
  if (merged.grade !== null) {
    params.set('grade', String(merged.grade));
  }
  if (merged.classNo !== null) {
    params.set('classNo', String(merged.classNo));
  }
  if (merged.studentNo !== null) {
    params.set('studentNo', String(merged.studentNo));
  }
  if (merged.searchField !== DEFAULT_POINT_ACCOUNT_SEARCH_FIELD) {
    params.set('searchField', merged.searchField);
  }
  if (merged.keyword) {
    params.set('keyword', merged.keyword);
  }
  if (merged.pageSize !== DEFAULT_POINT_ACCOUNT_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
    ? `${POINT_ACCOUNTS_PATH}?${queryString}`
    : POINT_ACCOUNTS_PATH;
}