import { expect, test, type Page } from '@playwright/test'

// Real mouse selection over the rendered chapter, against a mocked API: the interaction #4
// verified is exercised as a continuous drag, not through a preset button.
const original = 'Take a small step\nevery day.\n'
const fragments: [string, 'word' | 'space' | 'punctuation'][] = [
  ['Take', 'word'], [' ', 'space'], ['a', 'word'], [' ', 'space'], ['small', 'word'], [' ', 'space'],
  ['step', 'word'], ['\n', 'space'], ['every', 'word'], [' ', 'space'], ['day', 'word'], ['.', 'punctuation'], ['\n', 'space'],
]
let cp = 0
let utf16 = 0
const tokens = fragments.map(([text, kind]) => {
  const token = { text, kind, start: cp, end: cp + [...text].length, startUtf16: utf16, endUtf16: utf16 + text.length }
  cp = token.end
  utf16 = token.endUtf16
  return token
})
const book = { id: 1, title: 'Phrase chapter', language: 'en' }
const timestamps = { createdAt: '2026-01-01T00:00:00Z', updatedAt: '2026-01-01T00:00:00Z' }
const chapter = { id: 55, bookId: 1, ordinal: 1, title: 'Phrase chapter', status: 'ready', charCount: [...original].length, errorReason: '', errorMessage: '', jobId: 5, contentSha256: 'fictional-sha', originalText: original, ...timestamps }

async function openChapter(page: Page, options: { phrases?: unknown[]; onPhrase?: (body: Record<string, unknown>) => void } = {}) {
  const user = { id: 42, username: 'fictional-phrase', role: 'learner' }
  await page.addInitScript(() => sessionStorage.setItem('lexgo-learner-token', 'fictional-session'))
  await page.route('**/api/v1/**', async route => {
    const path = new URL(route.request().url()).pathname
    const method = route.request().method()
    let data: unknown = null
    let status = 200
    if (path === '/api/v1/me') data = user
    else if (path === '/api/v1/space') data = { ownerId: user.id, language: 'en' }
    else if (path === '/api/v1/books') data = { items: [] }
    else if (path === '/api/v1/chapters/55/tokens') data = { textSha256: 'fictional-sha', tokens, phrases: options.phrases ?? [] }
    else if (path === '/api/v1/chapters/55') data = { book, chapter, navigation: { previousChapterId: null, nextChapterId: null } }
    else if (path === '/api/v1/lookup') data = { status: 'not_found', query: 'Take', matchedForm: null, candidates: [], entries: [] }
    else if (path === '/api/v1/phrases' && method === 'POST') {
      options.onPhrase?.(route.request().postDataJSON() as Record<string, unknown>)
      status = 201
      data = {
        term: { id: 9, term: 'take a small', originalForm: 'Take a small', definition: '拿一小步', examples: [], status: 'new', level: 0, kind: 'phrase', wordCount: 3 },
        created: true,
      }
    } else if (path === '/api/v1/terms/9') data = { term: { id: 9, term: 'take a small', originalForm: 'Take a small', definition: '拿一小步', examples: ['Take a small step.'], status: 'new', level: 0, kind: 'phrase', wordCount: 3 } }
    await route.fulfill({ status, json: { code: 200, data } })
  })
  await page.goto('/chapters/55')
  await expect(page.locator('.reader-text')).toBeVisible()
}

/**
 * Drags from the centre of one word to the centre of another, like a person selecting text.
 *
 * A synthetic drag sometimes stops one word short or collapses entirely in Chromium, especially
 * while other tests load the same dev server, so the drag is repeated until the highlighted run
 * has the expected number of words. The retry condition is the property the test is about, not
 * just "a panel appeared": a real regression in selection handling still fails all attempts.
 */
async function dragWords(page: Page, from: string, to: string, words: number) {
  const word = page.locator('.reader-word')
  const start = word.filter({ hasText: new RegExp(`^${from}$`) }).first()
  const end = word.filter({ hasText: new RegExp(`^${to}$`) }).first()
  const range = page.getByTestId('phrase-range')
  for (let attempt = 1; attempt <= 4; attempt += 1) {
    // The boxes are read again on every attempt: an open panel reflows the page, so a cached
    // coordinate would drag to the wrong place and keep the retry failing for the same reason.
    const startBox = (await start.boundingBox())!
    const endBox = (await end.boundingBox())!
    const startX = startBox.x + startBox.width / 2
    const startY = startBox.y + startBox.height / 2
    await page.mouse.move(startX, startY)
    await page.mouse.down()
    // A couple of pixels first: the browser only starts extending the selection once the pointer
    // has actually moved, and a single jump can be treated as a click.
    await page.mouse.move(startX + 3, startY, { steps: 2 })
    await page.mouse.move(endBox.x + endBox.width / 2, endBox.y + endBox.height / 2, { steps: 12 })
    // Under load the browser may not have extended the selection by the time the button is
    // released, which is what produces a run that stops one word short.
    await page.waitForTimeout(80)
    await page.mouse.up()
    try {
      await expect(range).toContainText(`短语 · ${words} 个单词`, { timeout: 2500 })
      return
    } catch (reason) {
      if (attempt === 4) throw reason
      // Close whatever panel the partial selection opened, so the next attempt starts clean.
      await page.keyboard.press('Escape')
      await expect(page.locator('.lookup-panel')).toHaveCount(0)
    }
  }
}

test('drag a continuous phrase, save it and highlight it', async ({ page }) => {
  let body: Record<string, unknown> | undefined
  await openChapter(page, { onPhrase: value => { body = value } })

  await dragWords(page, 'Take', 'small', 3)
  const range = page.getByTestId('phrase-range')
  await expect(range).toContainText('短语 · 3 个单词')
  // A phrase that is not stored yet is labelled as a new entry.
  await expect(page.locator('.lookup-panel')).toContainText('新词条')
  await page.getByLabel(/^我的释义/).fill('拿一小步')
  await page.screenshot({ path: '../.local/evidence/issue11-phrase-selected.png' })
  await page.getByTestId('term-save').click()
  await expect(page.getByText('已保存 · 新词')).toBeVisible()
  // The code point range covers the whole run including its interior separator.
  expect(body).toMatchObject({ chapterId: 55, start: 0, end: 12, definition: '拿一小步', status: 'new' })
  // The saved phrase is underlined in the text.
  await expect(page.locator('.reader-word.is-phrase')).toHaveCount(3)
})

test('adjust the endpoints by whole words from the panel', async ({ page }) => {
  await openChapter(page)
  await dragWords(page, 'Take', 'small', 3)
  await expect(page.getByTestId('phrase-range')).toContainText('3 个单词')
  await page.getByTestId('range-end-right').click()
  await expect(page.getByTestId('phrase-range')).toContainText('4 个单词')
  await page.getByTestId('range-start-right').click()
  await expect(page.getByTestId('phrase-range')).toContainText('3 个单词')
  await page.getByTestId('range-start-left').click()
  await expect(page.getByTestId('phrase-range')).toContainText('4 个单词')
})

test('open a saved phrase from its highlight', async ({ page }) => {
  await openChapter(page, { phrases: [{ id: 9, status: 'new', wordCount: 3, startToken: 0, endToken: 4 }] })
  await expect(page.locator('.reader-word.is-phrase')).toHaveCount(3)
  await page.locator('.reader-word.is-phrase').first().click()
  await expect(page.getByTestId('phrase-range')).toContainText('已保存')
  await expect(page.getByLabel(/^我的释义/)).toHaveValue('拿一小步')
  await page.screenshot({ path: '../.local/evidence/issue11-phrase-saved.png' })
})

test('a phrase review card masks the whole run as one blank', async ({ page }) => {
  const user = { id: 42, username: 'fictional-phrase', role: 'learner' }
  await page.addInitScript(() => sessionStorage.setItem('lexgo-learner-token', 'fictional-session'))
  await page.route('**/api/v1/**', async route => {
    const path = new URL(route.request().url()).pathname
    let data: unknown = null
    if (path === '/api/v1/me') data = user
    else if (path === '/api/v1/space') data = { ownerId: user.id, language: 'en' }
    else if (path === '/api/v1/reviews/queue') {
      data = {
        items: [{
          id: 9, term: 'a small step', originalForm: 'a small step', definition: '一小步',
          examples: ['Take a small step, every day.'], status: 'new', level: 0, kind: 'phrase', wordCount: 3,
          dueAt: '2026-01-01T00:00:00Z', reviewCount: 0,
        }],
        total: 1,
      }
    }
    await route.fulfill({ json: { code: 200, data } })
  })
  await page.goto('/review')
  await expect(page.getByTestId('review-position')).toContainText('到期复习 · 1 / 1')
  await expect(page.getByText('Take _____, every day.')).toBeVisible()
  await expect(page.getByText('短语 · 3 个单词')).toBeVisible()
  await page.getByTestId('review-reveal').click()
  await expect(page.getByTestId('review-definition')).toHaveText('一小步')
  await page.screenshot({ path: '../.local/evidence/issue11-phrase-review.png' })
})