const express = require("express");
const multer = require("multer");
const pdf = require("pdf-parse");
const fs = require('fs');


const app = express();
app.use(express.json());
app.use(express.urlencoded({extended: true}));
app.use((req, res, next) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Headers", "Content-Type, x-requested-with");
  next();
});

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, "uploads/");
  },
  filename: function (req, file, cb) {
    cb(null, file.originalname);
  }
});

const options = {
  normalizeWhitespace: true,
  pdfjsDataRangeTransportFactory: function () {
    return new pdfjsDataRangeTransport();
  }
};

function extractTextFromPDF(pdfUrl) {
  return new Promise((resolve, reject) => {
    // 读取PDF文件
    const dataBuffer = fs.readFileSync(pdfUrl);

    // 提取文本
    pdf(dataBuffer).then(data => {
      const numPages = data.numpages;
      const extractedText = [];

      // 遍历每一页
      for (let i = 1; i <= numPages; i++) {
        const page = data.pages[i - 1];

        // 获取当前页的文本内容
        let pageText = page.text;

        // 排除页眉和页脚的文本
        const header = '页眉的文本';
        const footer = '页脚的文本';
        const regex = new RegExp(`(${header}|${footer})`, 'g');
        pageText = pageText.replace(regex, '');

        extractedText.push(pageText);
      }

      resolve(extractedText.join(' '));
    }).catch(error => {
      reject(error);
    });
  });
}

const upload = multer({storage: storage});
let hasPrinted = false;
app.post("/upload", upload.single("file"), (req, res) => {
  const filePath = req.file.path;
  extractTextFromPDF(filePath).then(text => {
    console.log(text);
  }).catch(error => {
    console.error(error);
  });
});
//   let dataBuffer = fs.readFileSync(filePath);
//   pdf(dataBuffer, options).then(function (data) {
//     if (!hasPrinted) {
//       console.log(data.text);
//       hasPrinted = true
//     }
//   });
// } catch (error) {
//   res.status(500).json({error: error.message});
// }
// hasPrinted = false
// });

app.listen(3000, () => {
  console.log("Server started on port 3000");
});