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系统标准技术文档_V1.0_2026-07-24.pdf')
  const task = pdfjs.getDocument({
    data: new Uint8Array(fs.readFileSync(pdfPath)),
    disableWorker: true
  })
  const pdf = await task.promise
  const requested = process.argv.slice(2).map(Number).filter(Number.isInteger)

  if (requested.length === 0) {
    for (let pageNumber = 1; pageNumber <= pdf.numPages; pageNumber++) {
      const page = await pdf.getPage(pageNumber)
      const content = await page.getTextContent()
      const text = content.items.map(item => item.str).join(' ').replace(/\s+/g, ' ').trim()
      console.log(`${pageNumber}\t${text.slice(0, 110)}`)
    }
    return
  }

  for (const pageNumber of requested) {
    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: 1.6 })
    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
    const outputPath = path.resolve(__dirname, `technical-pdf-page-${pageNumber}.png`)
    fs.writeFileSync(outputPath, canvas.toBuffer('image/png'))
    console.log(`Rendered: ${outputPath}`)
  }
  console.log(`PDF pages: ${pdf.numPages}`)
}

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