import path from 'path'
import { mkdtempSync, rmSync, existsSync } from 'fs'
import { join } from 'path'
import { tmpdir } from 'os'
import { test, expect, _electron as electron, type Page } from '@playwright/test'

const ROOT = path.join(import.meta.dirname, '..')

const LIGHT_THEMES = ['ricepaper', 'mist', 'teagarden'] as const

async function launchApp(userDataDir: string) {
  return electron.launch({
    args: [ROOT],
    env: {
      ...process.env,
      BILIN_E2E: '1',
      BILIN_E2E_USER_DATA: userDataDir
    }
  })
}

async function skipOnboarding(page: Page): Promise<void> {
  await page.waitForLoadState('domcontentloaded')
  await expect(page.locator('#app')).toBeVisible({ timeout: 20_000 })
  if (await page.getByText('欢迎使用笔临').isVisible()) {
    await page.getByRole('button', { name: '跳过' }).click()
    await expect(page.getByText('欢迎使用笔临')).toBeHidden({ timeout: 10_000 })
  }
}

async function openSettings(page: Page): Promise<void> {
  await page.getByRole('button', { name: /系统设置/ }).click()
  await expect(page.locator('#settings-page')).toBeVisible()
}

function parseRgb(color: string): [number, number, number] | null {
  const m = color.match(/rgba?\((\d+),\s*(\d+),\s*(\d+)/)
  if (!m) return null
  return [Number(m[1]), Number(m[2]), Number(m[3])]
}

function relativeLuminance(r: number, g: number, b: number): number {
  const [rs, gs, bs] = [r, g, b].map((c) => {
    const s = c / 255
    return s <= 0.03928 ? s / 12.92 : Math.pow((s + 0.055) / 1.055, 2.4)
  })
  return 0.2126 * rs + 0.7152 * gs + 0.0722 * bs
}

function contrastRatio(fg: string, bg: string): number {
  const fgRgb = parseRgb(fg)
  const bgRgb = parseRgb(bg)
  if (!fgRgb || !bgRgb) return 0
  const l1 = relativeLuminance(...fgRgb)
  const l2 = relativeLuminance(...bgRgb)
  const lighter = Math.max(l1, l2)
  const darker = Math.min(l1, l2)
  return (lighter + 0.05) / (darker + 0.05)
}

test.describe('Theme contrast', () => {
  let userDataDir: string

  test.beforeEach(() => {
    userDataDir = mkdtempSync(join(tmpdir(), 'bilin-e2e-contrast-'))
  })

  test.afterEach(() => {
    if (userDataDir && existsSync(userDataDir)) {
      try {
        rmSync(userDataDir, { recursive: true, force: true, maxRetries: 3, retryDelay: 200 })
      } catch {
        /* ignore */
      }
    }
  })

  for (const theme of LIGHT_THEMES) {
    test(`E2E-CONTRAST: ${theme} theme has readable form controls`, async () => {
      const app = await launchApp(userDataDir)
      const page = await app.firstWindow()
      await skipOnboarding(page)
      await openSettings(page)

      await page.getByTestId('settings-theme').selectOption(theme)
      await expect(page.locator('html')).toHaveAttribute('data-theme', theme)

      await expect(page.getByRole('heading', { name: '系统设置' })).toBeVisible()
      await expect(page.locator('.setting-item').first()).toBeVisible()

      const penNameOk = await page.evaluate(() => {
        const el = document.querySelector('[data-testid="settings-pen-name"]') as HTMLElement | null
        if (!el) return false
        const cs = getComputedStyle(el)
        const fg = cs.color
        const bg = cs.backgroundColor
        if (fg === 'rgba(0, 0, 0, 0)' || bg === 'rgba(0, 0, 0, 0)') return false
        if (fg === bg) return false
        return true
      })
      expect(penNameOk).toBe(true)

      const ratio = await page.evaluate(() => {
        const el = document.querySelector('[data-testid="settings-pen-name"]') as HTMLElement
        const cs = getComputedStyle(el)
        return { fg: cs.color, bg: cs.backgroundColor }
      })
      expect(contrastRatio(ratio.fg, ratio.bg)).toBeGreaterThanOrEqual(4.5)

      await app.close()
    })
  }

  test('E2E-CONTRAST: light themes show visible headings on main page', async () => {
    const app = await launchApp(userDataDir)
    const page = await app.firstWindow()
    await skipOnboarding(page)
    await openSettings(page)

    for (const theme of LIGHT_THEMES) {
      await page.getByTestId('settings-theme').selectOption(theme)
      await page.locator('.logo-area').click()
      await expect(page.locator('#settings-page')).toBeHidden()

      const headingVisible = await page.evaluate(() => {
        const selectors = ['h1', 'h2', 'button', '.setting-item']
        for (const sel of selectors) {
          const el = document.querySelector(`#app ${sel}`) as HTMLElement | null
          if (!el) continue
          const cs = getComputedStyle(el)
          if (cs.visibility === 'hidden' || cs.display === 'none') continue
          const fg = cs.color
          if (fg === 'rgba(0, 0, 0, 0)') continue
          return true
        }
        return false
      })
      expect(headingVisible).toBe(true)

      await page.getByRole('button', { name: '⚙ 系统设置' }).click()
      await expect(page.locator('#settings-page')).toBeVisible()
    }

    await app.close()
  })
})