import { test, expect } from '@playwright/test'
import { readFile } from 'fs/promises'
import { join } from 'path'
import {
  launchApp,
  stubOpenDialogSeq,
  stubSaveDialog,
  makeTmpDir,
  removeTmpDir,
  writeTextFixture,
  pasteText,
  dropFiles
} from './helpers'

/**
 * DiffLens E2E 主链路验收（对 build 产物运行真实 Electron）：
 * 覆盖 jsdom 单测无法触达的主进程解码 / 报告写盘 / 剪贴板 IPC / 偏好持久化生命周期。
 * 运行前必须先 npm run build。
 */

test.describe('启动与基础交互', () => {
  test('应用启动：窗口标题与双空态面板', async () => {
    const { app, window } = await launchApp()
    await expect(window).toHaveTitle('DiffLens')
    await expect(window.getByText('选择左侧文件')).toBeVisible()
    await expect(window.getByText('选择右侧文件')).toBeVisible()
    // 空态不出现导出入口
    await expect(window.getByRole('button', { name: '导出报告' })).toHaveCount(0)
    await app.close()
  })

  test('粘贴两侧文本：差异渲染与统计徽章', async () => {
    const { app, window } = await launchApp()
    await pasteText(window, 'left', 'alpha\nbeta\ngamma')
    await expect(window.getByRole('button', { name: '导出报告' })).toBeVisible()
    await pasteText(window, 'right', 'alpha\nBETA\ngamma')
    // 差异徽章与状态栏结论
    await expect(window.getByText('有差异')).toBeVisible()
    await expect(window.getByText('~1')).toBeVisible()
    // 修改行内容渲染（词级高亮行；exact 避免大小写不敏感的重复命中）
    await expect(window.getByText('beta', { exact: true })).toBeVisible()
    await expect(window.getByText('BETA', { exact: true })).toBeVisible()
    await app.close()
  })
})

test.describe('文件打开与编码识别（主进程真实解码链路）', () => {
  let dir: string

  test.beforeAll(async () => {
    dir = await makeTmpDir('difflens-e2e-enc-')
  })

  test.afterAll(async () => {
    await removeTmpDir(dir)
  })

  test('打开 GBK 与 UTF-8 BOM 文件：编码标注与内容正确渲染', async () => {
    const gbkPath = await writeTextFixture(
      dir,
      'gbk.txt',
      '中文内容第一行\n第二行数据',
      'gbk'
    )
    const bomPath = await writeTextFixture(dir, 'bom.txt', 'BOM 首行\nBOM 第二行', 'utf8-bom')
    const { app, window } = await launchApp()
    await stubOpenDialogSeq(app, [[gbkPath], [bomPath]])
    await window.getByRole('button', { name: '打开左侧' }).click()
    await expect(window.getByText('中文内容第一行')).toBeVisible()
    await window.getByRole('button', { name: '打开右侧' }).click()
    await expect(window.getByText('BOM 首行')).toBeVisible()
    // 面板头编码标注（主进程探测结果；exact 避免文件名 gbk.txt 的子串误匹配）
    await expect(window.locator('.pane-meta').filter({ hasText: 'GBK' })).toBeVisible()
    await expect(window.locator('.pane-meta').filter({ hasText: 'UTF-8 (BOM)' })).toBeVisible()
    await app.close()
  })

  test('大体积 GBK 文件：后台 worker 解码后完整渲染', async () => {
    // 约 300KB（≥ 解码 worker 快路径阈值 256KB）：走 worker_threads 后台解码链路
    const bigLines = Array.from({ length: 15000 }, (_, i) => `中文大文件行${i}数据`).join('\n')
    const bigPath = await writeTextFixture(dir, 'big-gbk.txt', bigLines, 'gbk')
    const { app, window } = await launchApp()
    await stubOpenDialogSeq(app, [[bigPath]])
    await window.getByRole('button', { name: '打开左侧' }).click()
    // 首行在视口内；末行在虚拟滚动视口外，以状态栏总行数断言完整性
    await expect(window.getByText('中文大文件行0数据')).toBeVisible()
    await expect(window.locator('.status-item').filter({ hasText: '15000 行' })).toBeVisible()
    await expect(window.locator('.pane-meta').filter({ hasText: 'GBK' })).toBeVisible()
    await app.close()
  })
})

test.describe('比较选项端到端', () => {
  test('忽略大小写与忽略所有空白组合生效', async () => {
    const { app, window } = await launchApp()
    await pasteText(window, 'left', 'alpha\nbeta')
    await pasteText(window, 'right', 'ALPHA\n beta')
    // 默认严格对比：两处差异
    await expect(window.getByText('有差异')).toBeVisible()
    // 仅忽略大小写：仍有行首空白差异
    await window.getByLabel('忽略大小写').check()
    await expect(window.getByText('有差异')).toBeVisible()
    // 再忽略所有空白：判为完全一致
    await window.getByLabel('忽略所有空白').check()
    await expect(window.getByText('两文件内容完全一致')).toBeVisible()
    await app.close()
  })

  test('字符级对比：跨行重组判为一致', async () => {
    const { app, window } = await launchApp()
    await pasteText(window, 'left', 'ab cd')
    await pasteText(window, 'right', 'ab\ncd')
    await expect(window.getByText('有差异')).toBeVisible()
    await window.getByLabel('字符级对比').check()
    await expect(window.getByText('两文件内容完全一致')).toBeVisible()
    await app.close()
  })

  test('字符级大输入：重算期间滚动位置不回弹（0.6.3 回退缺陷的回归锚）', async () => {
    // fixture 严格对齐用户实测场景：真实文件打开 + 行数不等（左 950 / 右 942：改 3 + 删 20 + 插 12），
    // 字符量约 4.7 万 > 重输入阈值（5000）→ 开字符级即进 worker 重路径
    const dir = await makeTmpDir('difflens-e2e-scroll-')
    try {
      const pad = (i: number): string => String(i).padStart(4, '0')
      const left = Array.from({ length: 950 }, (_, i) => `L${pad(i)}-abcdefghijklmnopqrstuvwxyz`)
      const right = [...left]
      right[300] = 'L0300-abcdefghijXlmnopqrstuvwxyz'
      right.splice(530, 20)
      right.splice(812, 0, ...Array.from({ length: 12 }, (_, k) => `N${pad(k)}-newcontent-${k}0987654321`))
      const lp = await writeTextFixture(dir, 'left.txt', left.join('\n'))
      const rp = await writeTextFixture(dir, 'right.txt', right.join('\n'))

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[lp], [rp]])
      await window.getByRole('button', { name: '打开左侧' }).click()
      await window.getByText('L0000-abcdefghijklmnopqrstuvwxyz').first().waitFor()
      await window.getByRole('button', { name: '打开右侧' }).click()
      await window.getByText('L0001-abcdefghijklmnopqrstuvwxyz').first().waitFor()

      // 开字符级（首次进入重路径：快路径结果兜底撑住容器高度，不塌陷归零）
      await window.getByLabel('字符级对比').check()
      await window.getByText('有差异').first().waitFor()

      // 滚到中部后二次触发重算（切选项）：computing 期间位置必须保持
      const scrollSel = '.pane-left .diff-scroll'
      await window.evaluate((s) => {
        const el = document.querySelector(s)
        el.scrollTop = 5000
        el.dispatchEvent(new Event('scroll'))
      }, scrollSel)
      expect(await window.evaluate((s) => document.querySelector(s).scrollTop, scrollSel)).toBe(5000)

      await window.getByLabel('忽略大小写').check()
      await window.waitForTimeout(150)
      // 关键断言：重算期间 scrollTop 不被钳制归零（缺陷版本会多级下坠到 0）
      const during = await window.evaluate((s) => document.querySelector(s).scrollTop, scrollSel)
      expect(during).toBeGreaterThanOrEqual(4000)

      // 重算完成后位置仍稳定
      await window.getByText('有差异').first().waitFor()
      await window.waitForTimeout(300)
      expect(await window.evaluate((s) => document.querySelector(s).scrollTop, scrollSel)).toBe(5000)

      // 滚到底部验证内容连续无重复渲染错乱
      await window.evaluate((s) => {
        const el = document.querySelector(s)
        el.scrollTop = el.scrollHeight
        el.dispatchEvent(new Event('scroll'))
      }, scrollSel)
      await window.waitForTimeout(300)
      const lastRow = await window.evaluate((s) => {
        const sc = document.querySelector(s)
        const rows = sc.querySelectorAll('.diff-row')
        return rows.length > 0 ? rows[rows.length - 1].textContent : ''
      }, scrollSel)
      expect(lastRow).toContain('L0949')
      await app.close()
    } finally {
      await removeTmpDir(dir)
    }
  })
})

test.describe('差异导航与视图', () => {
  test('F7 / Shift+F7 导航与仅看差异折叠', async () => {
    const { app, window } = await launchApp()
    await pasteText(window, 'left', 'a\nX1\nb\nY1\nc')
    await pasteText(window, 'right', 'a\nX2\nb\nY2\nc')
    await expect(window.getByText('1 / 2')).toBeVisible()
    await window.keyboard.press('F7')
    await expect(window.getByText('2 / 2')).toBeVisible()
    await window.keyboard.press('Shift+F7')
    await expect(window.getByText('1 / 2')).toBeVisible()
    // 仅看差异：未更改行折叠为提示行
    await window.getByLabel('仅看差异').check()
    await expect(window.getByText(/已折叠/).first()).toBeVisible()
    await app.close()
  })

  test('单文件视图搜索：Ctrl+F 聚焦、计数跳转、行内高亮与 Esc 清空（0.9.3）', async () => {
    const { app, window } = await launchApp()
    await pasteText(window, 'left', 'alpha\nfind target one\ngamma\nfind target two')
    await pasteText(window, 'right', 'alpha\nfind target one\ngamma\nfind target two')
    await expect(window.getByText('两文件内容完全一致')).toBeVisible()
    // Ctrl+F 聚焦搜索框
    await window.keyboard.press('Control+f')
    const input = window.getByPlaceholder('搜索内容… (Ctrl+F)')
    await expect(input).toBeFocused()
    // 输入关键字：即时计数与行内命中高亮
    await input.fill('target')
    await expect(window.locator('.search-count')).toHaveText('1 / 2')
    await expect(window.locator('.search-hit').first()).toBeVisible()
    // Enter 跳转下一个命中行（第一个命中行 active 定位）
    await window.keyboard.press('Enter')
    await expect(window.locator('.search-count')).toHaveText('2 / 2')
    await expect(window.locator('.diff-row.active .ln').first()).toHaveText('4')
    // Esc 清空关键字（计数复位消失）
    await window.keyboard.press('Escape')
    await expect(input).toHaveValue('')
    await expect(window.locator('.search-count')).toHaveText('')
    await app.close()
  })

  test('交换左右侧后面板文件互换', async () => {
    const dir = await makeTmpDir('difflens-e2e-swap-')
    try {
      const aPath = await writeTextFixture(dir, 'a.txt', 'aaa')
      const bPath = await writeTextFixture(dir, 'b.txt', 'bbb')
      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[aPath], [bPath]])
      await window.getByRole('button', { name: '打开左侧' }).click()
      await expect(window.locator('.pane-file').filter({ hasText: 'a.txt' })).toBeVisible()
      await window.getByRole('button', { name: '打开右侧' }).click()
      await expect(window.locator('.pane-file').filter({ hasText: 'b.txt' })).toBeVisible()
      await window.getByRole('button', { name: '⇄ 交换左右' }).click()
      // 面板头文件名互换（用 .pane-file 定位，避免与状态栏文件名混淆）
      const paneFiles = window.locator('.pane-file')
      await expect(paneFiles.nth(0)).toHaveText(/b\.txt/)
      await expect(paneFiles.nth(1)).toHaveText(/a\.txt/)
      await app.close()
    } finally {
      await removeTmpDir(dir)
    }
  })
})

test.describe('报告导出（主进程写盘链路）', () => {
  test('导出 HTML 报告：文件落盘且包含结论', async () => {
    const dir = await makeTmpDir('difflens-e2e-report-')
    try {
      const { app, window } = await launchApp()
      await pasteText(window, 'left', 'same\ndiff-left')
      await pasteText(window, 'right', 'same\ndiff-right')
      const savePath = join(dir, 'report.html')
      await stubSaveDialog(app, savePath)
      await window.getByRole('button', { name: '导出报告' }).click()
      await window.getByRole('button', { name: 'HTML 报告' }).click()
      await expect(window.getByText(/报告已保存/)).toBeVisible()
      const html = await readFile(savePath, 'utf-8')
      expect(html).toContain('<!doctype html>')
      expect(html).toContain('共 1 处不同：修改 1 行')
      // 统计卡与未更改行渲染（diff-left 被词级高亮拆分 span，不作整串断言）
      expect(html).toContain('~1')
      expect(html).toContain('same')
      await app.close()
    } finally {
      await removeTmpDir(dir)
    }
  })
})

test.describe('文件夹对比（主进程真实扫描链路）', () => {
  test('选择两个文件夹：状态判定、过滤与双击进入单文件对比', async () => {
    const root = await makeTmpDir('difflens-e2e-folder-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(join(leftDir, 'sub'), { recursive: true })
      await mkdir(join(rightDir, 'sub'), { recursive: true })
      await wf(join(leftDir, 'same.txt'), 'identical')
      await wf(join(rightDir, 'same.txt'), 'identical')
      await wf(join(leftDir, 'diff.txt'), 'left content\nsame tail')
      await wf(join(rightDir, 'diff.txt'), 'right content\nsame tail')
      await wf(join(leftDir, 'only-left.txt'), 'L')
      await wf(join(leftDir, 'sub', 'nested.txt'), 'nested L')
      await wf(join(rightDir, 'sub', 'nested.txt'), 'nested R')

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[leftDir], [rightDir]])
      await window.getByRole('button', { name: '对比文件夹' }).click()

      // 文件夹模式：路径卡片与统计徽章
      await expect(window.getByText('相同 1')).toBeVisible()
      await expect(window.getByText('不同 2')).toBeVisible()
      await expect(window.getByText('仅左 1')).toBeVisible()
      // 默认仅看差异：same.txt 被过滤，差异条目可见（树形视图显示文件尾段名）
      await expect(window.getByText('diff.txt')).toBeVisible()
      await expect(window.getByText('sub')).toBeVisible()
      await expect(window.getByText('nested.txt')).toBeVisible()
      await expect(window.getByText('same.txt')).toHaveCount(0)

      // 双击差异条目进入单文件对比
      await window.getByText('diff.txt').dblclick()
      await expect(window.getByText('left content')).toBeVisible()
      await expect(window.getByText('right content')).toBeVisible()
      await expect(window.getByText('有差异')).toBeVisible()
      await expect(window.getByRole('button', { name: '← 返回文件夹对比' })).toBeVisible()

      // 返回文件夹列表（扫描结果保留）
      await window.getByRole('button', { name: '← 返回文件夹对比' }).click()
      await expect(window.getByText('相同 1')).toBeVisible()
      await expect(window.getByText('diff.txt')).toBeVisible()
      await app.close()
    } finally {
      await removeTmpDir(root)
    }
  })

  test('增量重扫：修改文件后点重新扫描，状态正确更新', async () => {
    const root = await makeTmpDir('difflens-e2e-rescan-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(leftDir, { recursive: true })
      await mkdir(rightDir, { recursive: true })
      await wf(join(leftDir, 'same.txt'), 'identical')
      await wf(join(rightDir, 'same.txt'), 'identical')
      await wf(join(leftDir, 'diff.txt'), 'left v1')
      await wf(join(rightDir, 'diff.txt'), 'right v1')

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[leftDir], [rightDir]])
      await window.getByRole('button', { name: '对比文件夹' }).click()
      await expect(window.getByText('相同 1')).toBeVisible()
      await expect(window.getByText('不同 1')).toBeVisible()

      // 修改右侧 same.txt（真实 mtime 变化）→ 重新扫描（增量）→ 判定更新
      await wf(join(rightDir, 'same.txt'), 'identical changed')
      await window.getByRole('button', { name: '重新扫描' }).click()
      await expect(window.getByText('相同 0')).toBeVisible()
      await expect(window.getByText('不同 2')).toBeVisible()

      // 改回一致 → 再扫 → 恢复
      await wf(join(rightDir, 'same.txt'), 'identical')
      await window.getByRole('button', { name: '重新扫描' }).click()
      await expect(window.getByText('相同 1')).toBeVisible()
      await expect(window.getByText('不同 1')).toBeVisible()
      await app.close()
    } finally {
      await removeTmpDir(root)
    }
  })

  test('语义判等、树形折叠、搜索与文件夹报告导出', async () => {
    const root = await makeTmpDir('difflens-e2e-folder2-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(join(leftDir, 'sub'), { recursive: true })
      await mkdir(join(rightDir, 'sub'), { recursive: true })
      // 仅换行符差异（左 CRLF 右 LF）→ 语义同
      await wf(join(leftDir, 'crlf.txt'), 'line1\r\nline2\r\n')
      await wf(join(rightDir, 'crlf.txt'), 'line1\nline2\n')
      // 实质内容差异 → 不同
      await wf(join(leftDir, 'real.txt'), 'value = 1\n')
      await wf(join(rightDir, 'real.txt'), 'value = 2\n')
      // 完全一致（子目录）
      await wf(join(leftDir, 'sub', 'same.txt'), 'identical')
      await wf(join(rightDir, 'sub', 'same.txt'), 'identical')

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[leftDir], [rightDir]])
      await window.getByRole('button', { name: '对比文件夹' }).click()

      // 语义判等默认开：crlf.txt 计为语义同（统计徽章）
      await expect(window.getByText('语义同 1')).toBeVisible()
      await expect(window.getByText('不同 1')).toBeVisible()
      // 默认仅看差异：语义同被过滤，只剩 real.txt
      await expect(window.getByText('real.txt')).toBeVisible()
      await expect(window.getByText('crlf.txt')).toHaveCount(0)
      // 关闭仅看差异：树形展示（sub 目录行 + 语义同条目标注）
      await window.getByLabel('仅看差异').uncheck()
      await expect(window.getByText('crlf.txt')).toBeVisible()
      await expect(window.getByText('sub')).toBeVisible()
      await expect(window.getByText('same.txt')).toBeVisible()
      // 目录折叠/展开
      await window.getByText('sub').click()
      await expect(window.getByText('same.txt')).toHaveCount(0)
      await window.getByText('sub').click()
      await expect(window.getByText('same.txt')).toBeVisible()
      // 搜索过滤
      await window.getByPlaceholder('搜索文件名…').fill('crlf')
      await expect(window.getByText('crlf.txt')).toBeVisible()
      await expect(window.getByText('real.txt')).toHaveCount(0)
      await window.getByPlaceholder('搜索文件名…').fill('')
      // 导出文件夹报告（真实写盘）
      const savePath = join(root, 'folder-report.txt')
      await stubSaveDialog(app, savePath)
      await window.getByRole('button', { name: '导出报告' }).click()
      await window.getByRole('button', { name: '纯文本' }).click()
      await expect(window.getByText(/报告已保存/)).toBeVisible()
      const txt = await readFile(savePath, 'utf-8')
      expect(txt).toContain('DiffLens 文件夹对比报告')
      expect(txt).toContain('判定口径：语义判等开启')
      expect(txt).toContain('共 1 个文件存在差异')
      expect(txt).toContain('语义同')
      await app.close()
    } finally {
      await removeTmpDir(root)
    }
  })

  test('忽略规则：目录整树剪枝不参与对比（应用后重扫）', async () => {
    const root = await makeTmpDir('difflens-e2e-ignore-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(join(leftDir, 'node_modules', 'pkg'), { recursive: true })
      await mkdir(join(rightDir, 'node_modules', 'pkg'), { recursive: true })
      await wf(join(leftDir, 'keep.txt'), 'identical')
      await wf(join(rightDir, 'keep.txt'), 'identical')
      await wf(join(leftDir, 'node_modules', 'pkg', 'x.js'), 'left')
      await wf(join(rightDir, 'node_modules', 'pkg', 'x.js'), 'right')

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[leftDir], [rightDir]])
      await window.getByRole('button', { name: '对比文件夹' }).click()
      // 无规则：node_modules 内差异文件参与对比
      await expect(window.getByText('不同 1')).toBeVisible()
      await expect(window.getByText('x.js')).toBeVisible()

      // 应用忽略规则：node_modules/ 整树剪枝
      await window.getByRole('button', { name: '忽略规则' }).click()
      await window.getByPlaceholder(/每行一条/).fill('node_modules/')
      await window.getByText('应用并重扫').click()
      // 重扫完成：无差异（keep.txt 一致，node_modules 被忽略）
      await expect(window.getByText('不同 0')).toBeVisible()
      await expect(window.getByText('没有差异文件（两侧内容全部一致）')).toBeVisible()
      await expect(window.getByText('x.js')).toHaveCount(0)
      await app.close()
    } finally {
      await removeTmpDir(root)
    }
  })

  test('增量缓存跨会话持久化：落盘文件存在且重启后重扫正确', async () => {
    const root = await makeTmpDir('difflens-e2e-cachestore-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(leftDir, { recursive: true })
      await mkdir(rightDir, { recursive: true })
      await wf(join(leftDir, 'same.txt'), 'identical')
      await wf(join(rightDir, 'same.txt'), 'identical')
      await wf(join(leftDir, 'diff.txt'), 'left v1')
      await wf(join(rightDir, 'diff.txt'), 'right v1')

      // 第一实例：扫描后缓存异步落盘 userData/scan-cache.json
      const first = await launchApp()
      await stubOpenDialogSeq(first.app, [[leftDir], [rightDir]])
      await first.window.getByRole('button', { name: '对比文件夹' }).click()
      await expect(first.window.getByText('相同 1')).toBeVisible()
      const cachePath = await first.app.evaluate(({ app }) => app.getPath('userData')).then(
        (userData) => join(userData, 'scan-cache.json')
      )
      await first.app.close()

      // 落盘文件存在且含本目录对的缓存条目（等待异步写盘完成）
      let raw = ''
      for (let i = 0; i < 20; i++) {
        raw = await readFile(cachePath, 'utf-8').catch(() => '')
        if (raw.includes('same.txt')) break
        await new Promise((r) => setTimeout(r, 200))
      }
      expect(raw).toContain('same.txt')
      expect(raw).toContain('diff.txt')
      // 结构为合法存储（版本 + 目录对键）
      const stored = JSON.parse(raw)
      expect(stored.version).toBe(1)
      expect(Object.keys(stored.pairs).length).toBeGreaterThanOrEqual(1)

      // 第二实例（同 userData，渲染端无内存缓存）：主进程注入盘上缓存，重扫结果正确
      const second = await launchApp({ fresh: false })
      await stubOpenDialogSeq(second.app, [[leftDir], [rightDir]])
      await second.window.getByRole('button', { name: '对比文件夹' }).click()
      await expect(second.window.getByText('相同 1')).toBeVisible()
      await expect(second.window.getByText('不同 1')).toBeVisible()
      await second.app.close()
    } finally {
      await removeTmpDir(root)
    }
  })

  test('快照基线：保存后修复差异并新增文件，加载快照对照变迁', async () => {
    const root = await makeTmpDir('difflens-e2e-snapshot-')
    try {
      const leftDir = join(root, 'left')
      const rightDir = join(root, 'right')
      const { mkdir, writeFile: wf } = await import('fs/promises')
      await mkdir(leftDir, { recursive: true })
      await mkdir(rightDir, { recursive: true })
      await wf(join(leftDir, 'same.txt'), 'identical')
      await wf(join(rightDir, 'same.txt'), 'identical')
      await wf(join(leftDir, 'diff.txt'), 'left v1')
      await wf(join(rightDir, 'diff.txt'), 'right v1')

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[leftDir], [rightDir]])
      await window.getByRole('button', { name: '对比文件夹' }).click()
      await expect(window.getByText('相同 1')).toBeVisible()
      await expect(window.getByText('不同 1')).toBeVisible()

      // 保存快照（真实写盘）
      const snapPath = join(root, 'baseline.json')
      await stubSaveDialog(app, snapPath)
      await window.getByRole('button', { name: '保存快照' }).click()
      await expect(window.getByText(/快照已保存/)).toBeVisible()
      const snapRaw = await readFile(snapPath, 'utf-8')
      expect(snapRaw).toContain('"version": 1')
      expect(snapRaw).toContain('diff.txt')

      // 修复 diff.txt（两侧一致）+ 新增 new.txt → 重扫
      await wf(join(rightDir, 'diff.txt'), 'left v1')
      await wf(join(leftDir, 'new.txt'), 'n')
      await wf(join(rightDir, 'new.txt'), 'n')
      await window.getByRole('button', { name: '重新扫描' }).click()
      await expect(window.getByText('相同 3')).toBeVisible()

      // 加载快照对照：diff.txt 已修复、new.txt 新文件
      await stubOpenDialogSeq(app, [[snapPath]])
      await window.getByRole('button', { name: '加载快照' }).click()
      await expect(window.getByText(/已加载快照/)).toBeVisible()
      await expect(window.getByText('已修复 1')).toBeVisible()
      await expect(window.getByText('新文件 1')).toBeVisible()
      // 对照条目行（平铺）与变迁标注可见
      await expect(window.getByText('diff.txt')).toBeVisible()
      await expect(window.getByText('new.txt')).toBeVisible()
      // 对照模式导出报告：条目表为变迁对照表（真实写盘断言变迁明细）
      const cmpPath = join(root, 'compare-report.txt')
      await stubSaveDialog(app, cmpPath)
      await window.getByRole('button', { name: '导出报告' }).click()
      await window.getByRole('button', { name: '纯文本' }).click()
      await expect(window.getByText(/报告已保存/)).toBeVisible()
      const cmp = await readFile(cmpPath, 'utf-8')
      expect(cmp).toContain('快照对照：修复 1')
      expect(cmp).toContain('已修复')
      expect(cmp).toContain('新文件')
      expect(cmp).toContain('保持一致')
      // 退出对照恢复
      await window.getByRole('button', { name: '退出对照' }).click()
      await expect(window.getByText('相同 3')).toBeVisible()
      await app.close()
    } finally {
      await removeTmpDir(root)
    }
  })
})

test.describe('拖拽导入（真实 Chromium DataTransfer 链路）', () => {
  test('空面板拖入文件：内容渲染与文件名显示', async () => {
    const { app, window } = await launchApp()
    await dropFiles(window, '.pane-empty', [
      { name: 'dropped-left.txt', content: 'drag line 1\ndrag line 2' }
    ])
    // 文件名出现在面板头，内容渲染（file.arrayBuffer → decodeBuffer IPC → 编码探测全链路）
    await expect(window.locator('.pane-file').filter({ hasText: 'dropped-left.txt' })).toBeVisible()
    await expect(window.getByText('drag line 1').first()).toBeVisible()
    await app.close()
  })

  test('双侧拖入形成对比：差异渲染', async () => {
    const { app, window } = await launchApp()
    await dropFiles(window, '.pane-empty', [
      { name: 'a.txt', content: 'same\nleft-unique' }
    ])
    // 左侧装载后进入对比视图：右侧为 DiffView 面板（.pane-right），不再是空态
    await dropFiles(window, '.pane-right', [
      { name: 'b.txt', content: 'same\nright-unique' }
    ])
    await expect(window.getByText('有差异')).toBeVisible()
    await expect(window.getByText('left-unique').first()).toBeVisible()
    await expect(window.getByText('right-unique').first()).toBeVisible()
    await app.close()
  })

  test('拖入非文本扩展名被拒绝并提示', async () => {
    const { app, window } = await launchApp()
    await dropFiles(window, '.pane-empty', [
      { name: 'image.png', content: 'fake-binary', type: 'image/png' }
    ])
    await expect(window.getByText(/仅支持文本文件：image\.png/)).toBeVisible()
    // 保持空态（无导出入口）
    await expect(window.getByRole('button', { name: '导出报告' })).toHaveCount(0)
    await app.close()
  })

  test('多文件拖入提示已取第一个并加载首个文件', async () => {
    const { app, window } = await launchApp()
    await dropFiles(window, '.pane-empty', [
      { name: 'first.txt', content: 'first content' },
      { name: 'second.txt', content: 'second content' }
    ])
    await expect(window.getByText(/一次只能导入一个文件/)).toBeVisible()
    await expect(
      window.locator('.pane-file').filter({ hasText: 'first.txt' })
    ).toBeVisible()
    await app.close()
  })
})

test.describe('偏好持久化（跨实例重启）', () => {
  test('重启后恢复比较选项与视图开关', async () => {
    // 第一实例 fresh 清掉历史残留，建立干净基线后再写入偏好
    const first = await launchApp({ fresh: true })
    await pasteText(first.window, 'left', 'alpha')
    await first.window.getByLabel('忽略大小写').check()
    await first.window.getByLabel('仅看差异').check()
    await expect(first.window.getByLabel('忽略大小写')).toBeChecked()
    // 等 localStorage 写回完成再关闭
    await first.window.waitForTimeout(500)
    await first.app.close()

    // 同一 userData 下重启（不清理）：偏好应恢复
    const second = await launchApp({ fresh: false })
    await pasteText(second.window, 'left', 'alpha')
    await expect(second.window.getByLabel('忽略大小写')).toBeChecked()
    await expect(second.window.getByLabel('仅看差异')).toBeChecked()
    await second.app.close()
  })
})

test.describe('大文件性能基准（耗时上限断言）', () => {
  // 口径说明：万级行 diff 在 worker 后台实测为秒级；上限按慢机约 4 倍余量放宽
  // 防 CI flaky（用例超时 60s 兜底）。断言失败即性能回归，需排查引擎/IO 退化。
  test('5 万行多差异文件：后台计算完成在耗时上限内', async () => {
    const dir = await makeTmpDir('difflens-e2e-perf-diff-')
    try {
      const n = 50000
      const pad = (i: number): string => String(i).padStart(5, '0')
      const left = Array.from({ length: n }, (_, i) => `L${pad(i)}-${'x'.repeat(30)}`)
      const right = [...left]
      // 20 处分散修改（每 2500 行一处）
      for (let i = 0; i < n; i += 2500) right[i] = `R${pad(i)}-${'y'.repeat(30)}`
      const lp = await writeTextFixture(dir, 'big-left.txt', left.join('\n'))
      const rp = await writeTextFixture(dir, 'big-right.txt', right.join('\n'))

      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[lp], [rp]])
      await window.getByRole('button', { name: '打开左侧' }).click()
      await window.getByText('L00000-').first().waitFor()
      // 计时：打开右侧 → worker 重路径计算完成（有差异徽章出现）
      const t0 = Date.now()
      await window.getByRole('button', { name: '打开右侧' }).click()
      await window.getByText('有差异').first().waitFor()
      const elapsed = Date.now() - t0
      expect(elapsed).toBeLessThan(15000)
      // 完整性：双侧 5 万行均已加载
      await expect(window.locator('.status-item').filter({ hasText: '50000 行' })).toHaveCount(2)
      await app.close()
    } finally {
      await removeTmpDir(dir)
    }
  })

  test('大体积 GBK 文件：worker 后台解码渲染在耗时上限内', async () => {
    const dir = await makeTmpDir('difflens-e2e-perf-gbk-')
    try {
      // 约 300KB（≥ 解码 worker 快路径阈值 256KB），15000 行
      const bigLines = Array.from({ length: 15000 }, (_, i) => `中文大文件行${i}数据`).join('\n')
      const bigPath = await writeTextFixture(dir, 'big-gbk.txt', bigLines, 'gbk')
      const { app, window } = await launchApp()
      await stubOpenDialogSeq(app, [[bigPath]])
      const t0 = Date.now()
      await window.getByRole('button', { name: '打开左侧' }).click()
      // 完整渲染以状态栏总行数为准（末行在虚拟滚动视口外）
      await expect(
        window.locator('.status-item').filter({ hasText: '15000 行' })
      ).toBeVisible()
      const elapsed = Date.now() - t0
      expect(elapsed).toBeLessThan(10000)
      await expect(window.getByText('中文大文件行0数据')).toBeVisible()
      await app.close()
    } finally {
      await removeTmpDir(dir)
    }
  })
})