let PDFLib: any = null

interface PDFLibModule {
  PDFDocument: {
    load(bytes: ArrayBuffer, options?: { ignoreEncryption?: boolean }): Promise<any>
  }
  PDFName: {
    of(name: string): any
  }
  PDFDict: any
  PDFArray: any
}

const loadPdfLib = (): Promise<PDFLibModule> => {
  return new Promise((resolve, reject) => {
    if (PDFLib) {
      resolve(PDFLib)
      return
    }

    const script = document.createElement('script')
    script.src = '/static/js/pdf-lib.min.js'
    script.onload = () => {
      PDFLib = (window as any).PDFLib
      resolve(PDFLib)
    }
    script.onerror = reject
    document.head.appendChild(script)
  })
}

const checkActionForJavaScript = (
  action: any,
  PDFDict: any,
  PDFName: any,
  PDFArray: any,
): boolean => {
  if (!(action instanceof PDFDict)) return false

  const subtype = action.lookup(PDFName.of('S'))
  if (subtype?.toString() === '/JavaScript') {
    return true
  }

  const js = action.lookup(PDFName.of('JS'))
  if (js) {
    return true
  }

  const next = action.lookup(PDFName.of('Next'))
  if (next instanceof PDFArray) {
    for (let i = 0; i < next.size(); i++) {
      if (checkActionForJavaScript(next.lookup(i), PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  } else if (next instanceof PDFDict) {
    if (checkActionForJavaScript(next, PDFDict, PDFName, PDFArray)) {
      return true
    }
  }

  return false
}

const checkFieldForJavaScript = (
  field: any,
  PDFDict: any,
  PDFName: any,
  PDFArray: any,
): boolean => {
  if (!(field instanceof PDFDict)) return false

  const aa = field.lookup(PDFName.of('AA'))
  if (aa instanceof PDFDict) {
    const actionKeys = ['K', 'F', 'V', 'C', 'E', 'X', 'D', 'U', 'Fo', 'PO', 'PC', 'PV', 'PI']
    
    for (const key of actionKeys) {
      const action = aa.lookup(PDFName.of(key))
      if (action && checkActionForJavaScript(action, PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  const kids = field.lookup(PDFName.of('Kids'))
  if (kids instanceof PDFArray) {
    for (let i = 0; i < kids.size(); i++) {
      if (checkFieldForJavaScript(kids.lookup(i), PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  return false
}

const checkAcroFormForJavaScript = (
  acroForm: any,
  PDFDict: any,
  PDFName: any,
  PDFArray: any,
): boolean => {
  if (!(acroForm instanceof PDFDict)) return false

  const co = acroForm.lookup(PDFName.of('CO'))
  if (co instanceof PDFArray) {
    for (let i = 0; i < co.size(); i++) {
      if (checkFieldForJavaScript(co.lookup(i), PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  const fields = acroForm.lookup(PDFName.of('Fields'))
  if (fields instanceof PDFArray) {
    for (let i = 0; i < fields.size(); i++) {
      if (checkFieldForJavaScript(fields.lookup(i), PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  return false
}

const checkAnnotationForJavaScript = (
  annot: any,
  PDFDict: any,
  PDFName: any,
  PDFArray: any,
): boolean => {
  if (!(annot instanceof PDFDict)) return false

  const aa = annot.lookup(PDFName.of('AA'))
  if (aa instanceof PDFDict) {
    const actionKeys = ['E', 'X', 'D', 'U', 'Fo', 'Bl', 'PO', 'PC', 'PV', 'PI']
    
    for (const key of actionKeys) {
      const action = aa.lookup(PDFName.of(key))
      if (action && checkActionForJavaScript(action, PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  const action = annot.lookup(PDFName.of('A'))
  if (action && checkActionForJavaScript(action, PDFDict, PDFName, PDFArray)) {
    return true
  }

  return false
}

const checkPageForJavaScript = (
  page: any,
  PDFDict: any,
  PDFName: any,
  PDFArray: any,
): boolean => {
  if (!(page instanceof PDFDict)) return false

  const aa = page.lookup(PDFName.of('AA'))
  if (aa instanceof PDFDict) {
    const actionKeys = ['O', 'C']
    
    for (const key of actionKeys) {
      const action = aa.lookup(PDFName.of(key))
      if (action && checkActionForJavaScript(action, PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  const annots = page.lookup(PDFName.of('Annots'))
  if (annots instanceof PDFArray) {
    for (let i = 0; i < annots.size(); i++) {
      if (checkAnnotationForJavaScript(annots.lookup(i), PDFDict, PDFName, PDFArray)) {
        return true
      }
    }
  }

  return false
}

const checkPdfJavaScript = async (bytes: ArrayBuffer): Promise<boolean> => {
  if (!PDFLib) {
    console.error('PDFLib not loaded')
    return false
  }

  try {
    const { PDFDocument, PDFName, PDFDict, PDFArray } = PDFLib
    const pdfDoc = await PDFDocument.load(bytes, { ignoreEncryption: true })
    const catalog = pdfDoc.catalog

    const names = catalog.lookup(PDFName.of('Names'))
    if (names instanceof PDFDict) {
      const javaScriptDict = names.lookup(PDFName.of('JavaScript'))
      if (javaScriptDict instanceof PDFDict) {
        console.log('检测到文档级 JavaScript')
        return true
      }
    }

    const openAction = catalog.lookup(PDFName.of('OpenAction'))
    if (openAction && checkActionForJavaScript(openAction, PDFDict, PDFName, PDFArray)) {
      console.log('检测到 OpenAction 中的 JavaScript')
      return true
    }

    const acroForm = catalog.lookup(PDFName.of('AcroForm'))
    if (acroForm && checkAcroFormForJavaScript(acroForm, PDFDict, PDFName, PDFArray)) {
      console.log('检测到表单中的 JavaScript')
      return true
    }

    const pages = catalog.lookup(PDFName.of('Pages'))
    if (pages instanceof PDFDict) {
      const kids = pages.lookup(PDFName.of('Kids'))
      if (kids instanceof PDFArray) {
        for (let i = 0; i < kids.size(); i++) {
          const page = kids.lookup(i)
          if (page instanceof PDFDict && checkPageForJavaScript(page, PDFDict, PDFName, PDFArray)) {
            console.log('检测到页面中的 JavaScript')
            return true
          }
        }
      }
    }

    return false
  } catch (error) {
    console.error('Error checking JavaScript:', error)
    return false
  }
}

export {
  loadPdfLib,
  checkPdfJavaScript,
}