import { getPaginationState } from "../pagination";

// The component module imports view-layer deps (`@expo/vector-icons`,
// `react-native-reanimated` via Button) that the unit-suite babel transform
// does not process. The shared setup stubs `react-native` / `nativewind`;
// stub the rest here so the pure helper under test loads without a render
// runtime. `jest.mock` is hoisted above the import by babel-plugin-jest-hoist
// (same pattern as the existing context tests).
jest.mock("@expo/vector-icons", () => ({ Ionicons: "Ionicons" }));
jest.mock("react-native-reanimated", () => ({
  __esModule: true,
  default: { View: "Animated.View" },
  useSharedValue: () => ({ value: 0 }),
  useAnimatedStyle: () => ({}),
  withTiming: (v: number) => v,
}));

describe("getPaginationState", () => {
  it("derives total pages and item range from page/size/total", () => {
    const s = getPaginationState(1, 10, 25);
    expect(s.totalPages).toBe(3);
    expect(s.currentPage).toBe(1);
    expect(s.rangeStart).toBe(1);
    expect(s.rangeEnd).toBe(10);
  });

  it("computes the trailing partial-page range", () => {
    const s = getPaginationState(3, 10, 25);
    expect(s.currentPage).toBe(3);
    expect(s.rangeStart).toBe(21);
    expect(s.rangeEnd).toBe(25);
  });

  it("disables prev on the first page", () => {
    const s = getPaginationState(1, 10, 25);
    expect(s.canPrev).toBe(false);
    expect(s.canNext).toBe(true);
  });

  it("disables next on the last page", () => {
    const s = getPaginationState(3, 10, 25);
    expect(s.canNext).toBe(false);
    expect(s.canPrev).toBe(true);
  });

  it("disables both controls when a single page holds everything", () => {
    const s = getPaginationState(1, 10, 4);
    expect(s.totalPages).toBe(1);
    expect(s.canPrev).toBe(false);
    expect(s.canNext).toBe(false);
  });

  it("reports an empty range with no items but still one page", () => {
    const s = getPaginationState(1, 10, 0);
    expect(s.totalPages).toBe(1);
    expect(s.rangeStart).toBe(0);
    expect(s.rangeEnd).toBe(0);
    expect(s.canPrev).toBe(false);
    expect(s.canNext).toBe(false);
  });

  it("clamps an out-of-range page up or down", () => {
    expect(getPaginationState(99, 10, 25).currentPage).toBe(3);
    expect(getPaginationState(-5, 10, 25).currentPage).toBe(1);
    expect(getPaginationState(0, 10, 25).currentPage).toBe(1);
  });

  it("tolerates degenerate page sizes by flooring to at least one", () => {
    const s = getPaginationState(1, 0, 5);
    expect(s.totalPages).toBe(5);
    expect(s.rangeEnd).toBe(1);
  });
});