import { describe, expect, it } from "vitest";
import {
  DAY_PAGE_SIZE_OPTIONS,
  DEFAULT_DAY_PAGE_SIZE,
  asDayPageSize,
  findItemPageIndex,
  formatDayPaginationSummary,
  nextSearchPageIfOutOfRange,
  pageIndexForItem,
  paginateItems,
  pickBoardPager,
  shouldShowDayPagination,
  shouldShowSearchPagination,
} from "@/domain/work-orders/utils/day-pagination";

describe("day pagination utils (SH-241)", () => {
  it("defaults to 50 and exposes 25/50/100/200", () => {
    expect(DEFAULT_DAY_PAGE_SIZE).toBe(50);
    expect(DAY_PAGE_SIZE_OPTIONS).toEqual([25, 50, 100, 200]);
    expect(asDayPageSize(200)).toBe(200);
    expect(asDayPageSize(13)).toBe(DEFAULT_DAY_PAGE_SIZE);
  });

  it("paginates 60 items at 50 per page", () => {
    const items = Array.from({ length: 60 }, (_, index) => index);
    const first = paginateItems(items, 0, 50);
    expect(first.visible).toHaveLength(50);
    expect(first.pageCount).toBe(2);
    const second = paginateItems(items, 1, 50);
    expect(second.visible).toEqual(items.slice(50));
  });

  it("re-paginates immediately when page size changes", () => {
    const items = Array.from({ length: 60 }, (_, index) => index);
    expect(paginateItems(items, 0, 25).visible).toHaveLength(25);
    expect(paginateItems(items, 0, 25).pageCount).toBe(3);
  });

  it("clamps an out-of-range page to the last page", () => {
    const paged = paginateItems([1, 2, 3], 9, 2);
    expect(paged.pageIndex).toBe(1);
    expect(paged.visible).toEqual([3]);
  });

  it("shows pagination in day view even when the page is not full", () => {
    expect(
      shouldShowDayPagination({
        flatListMode: false,
        isLoading: false,
        noSearchResults: false,
      }),
    ).toBe(true);
  });

  it("hides pagination in flat-list / loading / empty search", () => {
    expect(
      shouldShowDayPagination({
        flatListMode: true,
        isLoading: false,
        noSearchResults: false,
      }),
    ).toBe(false);
    expect(
      shouldShowDayPagination({
        flatListMode: false,
        isLoading: true,
        noSearchResults: false,
      }),
    ).toBe(false);
    expect(
      shouldShowDayPagination({
        flatListMode: false,
        isLoading: false,
        noSearchResults: true,
      }),
    ).toBe(false);
  });

  it("shows search pagination when advanced filters return rows", () => {
    expect(shouldShowSearchPagination({ isLoading: false, hasResults: true })).toBe(true);
    expect(shouldShowSearchPagination({ isLoading: true, hasResults: true })).toBe(false);
    expect(shouldShowSearchPagination({ isLoading: false, hasResults: false })).toBe(false);
  });

  it("shows search pagination when the current page is empty but totalCount is positive", () => {
    const pager = pickBoardPager({
      advActive: true,
      isLoading: false,
      noSearchResults: false,
      advResultCount: 0,
      search: { page: 99, pageSize: 50, totalCount: 1778 },
      day: {
        pageSize: 50,
        pageIndex: 0,
        pageCount: 1,
        itemCount: 0,
        footerLabel: "Mon · 08/17",
      },
    });
    expect(pager.show).toBe(true);
    expect(pager.itemCount).toBe(1778);
    expect(pager.pageCount).toBe(36);
    expect(pager.pageIndex).toBe(35);
    expect(pager.footerLabel).toBe("Results");
  });

  it("pages a 1778-row search at 50 per page without dumping the universe", () => {
    const pager = pickBoardPager({
      advActive: true,
      isLoading: false,
      noSearchResults: false,
      advResultCount: 50,
      search: { page: 0, pageSize: 50, totalCount: 1778 },
      day: {
        pageSize: 50,
        pageIndex: 0,
        pageCount: 1,
        itemCount: 0,
        footerLabel: "Mon · 08/17",
      },
    });
    expect(pager.show).toBe(true);
    expect(pager.itemCount).toBe(1778);
    expect(pager.pageCount).toBe(36);
    expect(pager.pageIndex).toBe(0);
    expect(pager.footerLabel).toBe("Results");
  });

  it("maps a row past the first page onto page 2 at the default size", () => {
    const items = Array.from({ length: 60 }, (_, index) => ({ id: `wo-${index}` }));
    expect(pageIndexForItem(50, 50)).toBe(1);
    expect(findItemPageIndex(items, "wo-55", 50)).toBe(1);
    expect(findItemPageIndex(items, "missing", 50)).toBeNull();
  });

  it("formats the AAP footer summary", () => {
    expect(formatDayPaginationSummary("Mon · 06/01", 9)).toBe("MON · 06/01 · 9 items");
    expect(formatDayPaginationSummary("Tue · 06/02", 1)).toBe("TUE · 06/02 · 1 item");
  });
});

describe("nextSearchPageIfOutOfRange", () => {
  it("returns the last valid page when a search shrinks to one page", () => {
    expect(nextSearchPageIfOutOfRange({ page: 1, pageSize: 50, totalCount: 40 })).toBe(0);
  });

  it("leaves a still-valid second page alone", () => {
    expect(nextSearchPageIfOutOfRange({ page: 1, pageSize: 50, totalCount: 60 })).toBeNull();
  });

  it("does not pull an empty result set onto page 1", () => {
    expect(nextSearchPageIfOutOfRange({ page: 1, pageSize: 50, totalCount: 0 })).toBeNull();
  });

  it("leaves the last valid page alone", () => {
    expect(nextSearchPageIfOutOfRange({ page: 0, pageSize: 50, totalCount: 40 })).toBeNull();
  });
});