const {
    SupportedTextSplitterLanguages,
    RecursiveCharacterTextSplitter,
    TokenTextSplitter
  } = require("langchain/text_splitter");

var mammoth = require("mammoth");
const fs = require('fs');
const pdf = require('pdf-parse');

async function main(){
 
    // 加载器提取纯文本
    let data = await pdfLoader("../data/pgvector.pdf")
    let text = data.text;
    console.log(text)
    const splitter = new TokenTextSplitter({
        encodingName: "gpt2",
        chunkSize: 500,
        chunkOverlap: 0,
    });
    const output = await splitter.createDocuments([text]);
    console.log(output)
  
    // 文本提取文本块
    let html = await docsLoader("../data/pgvector.docx")
    const splitter = RecursiveCharacterTextSplitter.fromLanguage("html", {
        chunkSize: 4096,
        chunkOverlap: 20,
      });
    const output = await splitter.createDocuments([html]);
    
    console.log(output);
    console.log(JSON.stringify(output[0]));
        
}
main()


async function docsLoader(path){
    return new Promise(resolve=>{
        mammoth.convertToHtml({path:  path})
        .then(function(result){
            var html = result.value; // The generated HTML
            var messages = result.messages; // Any messages, such as warnings during conversion
            console.log(html)
            console.log(messages)
            resolve(html)
        })
        .catch(function(error) {
            console.error(error);
        });
    })
}

async function pdfLoader(path){
    
    let dataBuffer = fs.readFileSync(path);
    return new Promise(resolve=>{
        pdf(dataBuffer).then(function(data) {
        
            // number of pages
            console.log(data.numpages);
            // number of rendered pages
            console.log(data.numrender);
            // PDF info
            console.log(data.info);
            // PDF metadata
            console.log(data.metadata); 
            // PDF.js version
            // check https://mozilla.github.io/pdf.js/getting_started/
            console.log(data.version);
            // PDF text
            console.log(data.text); 
            resolve(data)
        });
    })

}