import { describe, expect, it } from 'vitest';

import {
  buildTemplateRows,
  computeTemplateGridColumns,
  computeTemplateGridLayout,
  computeTemplateGridLayoutWithScrollbar,
  computeTemplateRowHeight,
  TEMPLATE_CARD_ACTIONS_HEIGHT,
  TEMPLATE_CARD_GAP,
  TEMPLATE_CARD_META_HEIGHT,
  TEMPLATE_CARD_MIN_WIDTH,
  TEMPLATE_CARD_SUMMARY_HEIGHT,
  TEMPLATE_CARD_TAGS_HEIGHT,
  TEMPLATE_CARD_TEXT_GAP,
  TEMPLATE_CARD_TEXT_HEIGHT,
  TEMPLATE_CARD_TEXT_PADDING,
  TEMPLATE_CARD_TITLE_HEIGHT,
} from '../src/features/template-library/templateLibraryGrid';
import type { GameTemplateEntry } from '../src/features/template-library/templateLibraryModel';

function entry(id: string): GameTemplateEntry {
  return {
    id,
    title: id,
    summary: '',
    tags: [],
    runtime: 'html',
    engine: 'phaser',
    engineVersion: '4.2.1',
    templateVersion: '0.1.0',
    updatedAt: '2026-09-17T00:00:00Z',
    entry: 'game/index.html',
    zipUrl: `https://oss.example/templates/v1/${id}/template.zip`,
    zipSizeBytes: 1024,
    zipSha256: 'a'.repeat(64),
    coverUrl: `https://oss.example/templates/v1/${id}/cover.svg`,
    coverWidth: 960,
    coverHeight: 540,
    installed: false,
    installedVersion: null,
    installedAtMillis: null,
  };
}

describe('computeTemplateGridColumns', () => {
  it('fits as many min-width columns as the container allows', () => {
    expect(computeTemplateGridColumns(0)).toBe(1);
    expect(computeTemplateGridColumns(200)).toBe(1);
    expect(computeTemplateGridColumns(TEMPLATE_CARD_MIN_WIDTH)).toBe(1);
    // 两列边界：2*250 + 14 = 514
    const twoColumnWidth = 2 * TEMPLATE_CARD_MIN_WIDTH + TEMPLATE_CARD_GAP;
    expect(computeTemplateGridColumns(twoColumnWidth)).toBe(2);
    expect(computeTemplateGridColumns(twoColumnWidth - 1)).toBe(1);
    // 1200px：4 列（(1200+14)/(250+14) = 4.59）
    expect(computeTemplateGridColumns(1200)).toBe(4);
  });
});

describe('computeTemplateRowHeight', () => {
  it('budgets the same height the card rows actually need', () => {
    // 这些数字对应 TemplateCard 的 `h-5`/`h-4`/`h-8`/`h-5.5`/`h-7` 与 `p-3`/`gap-2`：
    // 行高契约比真实内容小，被截断的就是卡片里的标题与简介。
    expect(TEMPLATE_CARD_TITLE_HEIGHT).toBe(20);
    expect(TEMPLATE_CARD_META_HEIGHT).toBe(16);
    expect(TEMPLATE_CARD_SUMMARY_HEIGHT).toBe(32);
    expect(TEMPLATE_CARD_TAGS_HEIGHT).toBe(22);
    expect(TEMPLATE_CARD_ACTIONS_HEIGHT).toBe(28);
    expect(TEMPLATE_CARD_TEXT_PADDING).toBe(12);
    expect(TEMPLATE_CARD_TEXT_GAP).toBe(8);
    expect(TEMPLATE_CARD_TEXT_HEIGHT).toBe(174);
  });

  it('keeps cover ratio + fixed text block', () => {
    // 列宽 300 → 卡片 286 → 封面 286*9/16 = 160.875 → 161
    expect(computeTemplateRowHeight(300)).toBe(
      161 + TEMPLATE_CARD_TEXT_HEIGHT + TEMPLATE_CARD_GAP,
    );
    // 极窄时按最小卡片宽度兜底，避免行高被压成 0
    expect(computeTemplateRowHeight(10)).toBeGreaterThan(
      TEMPLATE_CARD_TEXT_HEIGHT,
    );
  });
});

describe('computeTemplateGridLayout', () => {
  it('derives columns, row height and row count for a big library', () => {
    const layout = computeTemplateGridLayout({
      containerWidth: 1200,
      itemCount: 1000,
    });
    expect(layout.columnCount).toBe(4);
    expect(layout.columnWidth).toBe(300);
    expect(layout.rowHeight).toBe(
      161 + TEMPLATE_CARD_TEXT_HEIGHT + TEMPLATE_CARD_GAP,
    );
    expect(layout.rowCount).toBe(250);
    // 虚拟列表只渲染可视行，滚动高度仍由总行数决定
    expect(layout.rowCount * layout.rowHeight).toBeGreaterThan(80000);
  });

  it('handles inline and empty libraries', () => {
    expect(
      computeTemplateGridLayout({ containerWidth: 0, itemCount: 5 }),
    ).toEqual({
      columnCount: 1,
      columnWidth: 1,
      rowHeight: computeTemplateRowHeight(1),
      rowCount: 5,
    });
    expect(
      computeTemplateGridLayout({ containerWidth: 1200, itemCount: 0 })
        .rowCount,
    ).toBe(0);
  });
});

describe('computeTemplateGridLayoutWithScrollbar', () => {
  const innerWidth = (layout: { columnCount: number; columnWidth: number }) =>
    layout.columnCount * layout.columnWidth;

  it('reserves the classic scrollbar width once the grid scrolls vertically', () => {
    // 经典滚动条（Windows/WebView2 ≈ 17px）不在包裹层宽度里，不预留就会多出一条横向滚动条。
    const plain = computeTemplateGridLayout({
      containerWidth: 1184,
      itemCount: 13,
    });
    const layout = computeTemplateGridLayoutWithScrollbar({
      containerWidth: 1184,
      itemCount: 13,
      viewportHeight: 500,
      scrollbarWidth: 17,
    });

    expect(layout.columnCount).toBe(4);
    // 内层宽度必须落在竖滚动条左侧的可用宽度里，否则又会出现横向滚动条。
    expect(innerWidth(layout)).toBeLessThanOrEqual(1184 - 17);
    expect(innerWidth(layout)).toBeLessThan(innerWidth(plain));
    // 行高仍按预留后的列宽算，卡片内容不会被压。
    expect(layout.rowHeight).toBe(computeTemplateRowHeight(layout.columnWidth));
  });

  it('keeps the plain layout when nothing overflows or the scrollbar is an overlay', () => {
    const plain = computeTemplateGridLayout({
      containerWidth: 1184,
      itemCount: 4,
    });
    // 只有一行：不会竖向滚动，不需要预留，右侧不留白边。
    expect(
      computeTemplateGridLayoutWithScrollbar({
        containerWidth: 1184,
        itemCount: 4,
        viewportHeight: 900,
        scrollbarWidth: 17,
      }),
    ).toEqual(plain);
    // overlay 滚动条占宽 0：与不预留完全一致。
    expect(
      computeTemplateGridLayoutWithScrollbar({
        containerWidth: 1184,
        itemCount: 13,
        viewportHeight: 500,
        scrollbarWidth: 0,
      }),
    ).toEqual(
      computeTemplateGridLayout({ containerWidth: 1184, itemCount: 13 }),
    );
  });
});

describe('buildTemplateRows', () => {
  it('chunks entries per row and pads the tail with nulls', () => {
    const rows = buildTemplateRows([entry('a'), entry('b'), entry('c')], 2);
    expect(rows).toHaveLength(2);
    expect(rows[0]?.map((item) => item?.id)).toEqual(['a', 'b']);
    expect(rows[1]?.map((item) => item?.id ?? null)).toEqual(['c', null]);
  });

  it('returns no rows for an invalid column count', () => {
    expect(buildTemplateRows([entry('a')], 0)).toEqual([]);
  });
});