const fs = require('fs')
const path = require('path')
const { createCanvas, DOMMatrix, ImageData, Path2D } = require('@napi-rs/canvas')

global.DOMMatrix = DOMMatrix
global.ImageData = ImageData
global.Path2D = Path2D
if (!process.getBuiltinModule) process.getBuiltinModule = name => require(name)

async function main() {
  const pdfjs = await import('pdfjs-dist/legacy/build/pdf.mjs')
  const root = path.resolve(__dirname, '..', '..')
  const pdfPath = path.resolve(root, 'doc', '大连元利流体技术有限公司MES系统用户操作手册_V1.1_2026-07-23.pdf')
  const pageNumber = Number(process.argv[2] || 1)
  const outputPath = path.resolve(__dirname, `pdf-page-${pageNumber}.png`)
  const task = pdfjs.getDocument({ data: new Uint8Array(fs.readFileSync(pdfPath)), disableWorker: true })
  const pdf = await task.promise
  if (pageNumber < 1 || pageNumber > pdf.numPages) throw new Error(`Page ${pageNumber} is outside 1-${pdf.numPages}`)
  const page = await pdf.getPage(pageNumber)
  const viewport = page.getViewport({ scale: 1.5 })
  const canvas = createCanvas(Math.ceil(viewport.width), Math.ceil(viewport.height))
  const context = canvas.getContext('2d')
  context.fillStyle = '#ffffff'
  context.fillRect(0, 0, canvas.width, canvas.height)
  await page.render({ canvasContext: context, viewport }).promise
  fs.writeFileSync(outputPath, canvas.toBuffer('image/png'))
  console.log(`PDF pages: ${pdf.numPages}`)
  console.log(`Rendered: ${outputPath}`)
}

main().catch(error => {
  console.error(error.stack || error.message)
  process.exitCode = 1
})