import { beforeEach, describe, expect, test } from 'vitest';
import {
  clampSideWidth,
  HANDLES_TOTAL,
  maxSideWidth,
  PANE_DEFAULT,
  PANE_MIN,
  sideWidthValue,
  usePanesStore,
} from './PanesStore';

const store = () => usePanesStore.getState();

describe('clampSideWidth', () => {
  // A roomy container where nothing is constrained.
  const W = 1400;

  test('passes a comfortable width through unchanged', () => {
    expect(clampSideWidth('library', 300, W, PANE_DEFAULT.preview)).toBe(300);
    expect(clampSideWidth('preview', 400, W, PANE_DEFAULT.library)).toBe(400);
  });

  test('never goes below the pane minimum', () => {
    expect(clampSideWidth('library', 50, W, PANE_DEFAULT.preview)).toBe(PANE_MIN.library);
    expect(clampSideWidth('preview', 10, W, PANE_DEFAULT.library)).toBe(PANE_MIN.preview);
  });

  test('caps the width so the editor keeps at least its minimum', () => {
    const other = PANE_DEFAULT.preview;
    const max = W - other - HANDLES_TOTAL - PANE_MIN.editor;
    // Asking for far more than the editor can spare clamps to that maximum.
    expect(clampSideWidth('library', W, W, other)).toBe(max);
    // The editor sits exactly at its minimum at that point.
    expect(W - max - other - HANDLES_TOTAL).toBe(PANE_MIN.editor);
  });

  test('a container too narrow for all minimums still never drops below the min', () => {
    // 500px total can't fit library(180)+preview(240)+editor(320)+handles.
    expect(clampSideWidth('library', 300, 500, PANE_MIN.preview)).toBe(PANE_MIN.library);
  });
});

describe('sideWidthValue (aria-valuenow, 0–100 per WAI-ARIA APG window splitter)', () => {
  const W = 1400;

  test('reports 0 at the pane minimum and 100 at the pane maximum', () => {
    const other = PANE_DEFAULT.preview;
    const max = maxSideWidth('library', W, other);
    expect(sideWidthValue('library', PANE_MIN.library, W, other)).toBe(0);
    expect(sideWidthValue('library', max, W, other)).toBe(100);
  });

  test('reports the midpoint as ~50', () => {
    const other = PANE_DEFAULT.preview;
    const mid = (PANE_MIN.library + maxSideWidth('library', W, other)) / 2;
    expect(sideWidthValue('library', mid, W, other)).toBe(50);
  });

  test('clamps out-of-range widths into 0–100', () => {
    const other = PANE_DEFAULT.preview;
    expect(sideWidthValue('library', 0, W, other)).toBe(0);
    expect(sideWidthValue('library', 99999, W, other)).toBe(100);
  });

  test('returns null before layout is known (container width 0)', () => {
    expect(sideWidthValue('library', 280, 0, PANE_DEFAULT.preview)).toBeNull();
  });

  test('returns null when the range has collapsed (container too narrow)', () => {
    // 500px can't fit all the minimums, so min == max and there is no range.
    expect(sideWidthValue('library', 200, 500, PANE_MIN.preview)).toBeNull();
  });
});

describe('usePanesStore', () => {
  beforeEach(() =>
    store().hydrate({ libraryWidth: PANE_DEFAULT.library, previewWidth: PANE_DEFAULT.preview }),
  );

  test('setWidth updates the targeted side only', () => {
    store().setWidth('library', 320);
    expect(store().libraryWidth).toBe(320);
    expect(store().previewWidth).toBe(PANE_DEFAULT.preview);

    store().setWidth('preview', 420);
    expect(store().previewWidth).toBe(420);
    expect(store().libraryWidth).toBe(320);
  });

  test('hydrate fills missing values from defaults', () => {
    store().hydrate({ libraryWidth: 250 });
    expect(store().libraryWidth).toBe(250);
    expect(store().previewWidth).toBe(PANE_DEFAULT.preview);
  });
});