const express = require('express');
const fs = require('fs');
const app = express(); 

const AdvancableBuffer = require('./backend/utilities/AdvancableBuffer.js');
  
// handling CORS 
app.use((req, res, next) => { 
    res.header("Access-Control-Allow-Origin",  
               "http://localhost:4200"); 
    res.header("Access-Control-Allow-Headers",  
               "Origin, X-Requested-With, Content-Type, Accept"); 
    next(); 
}); 
  
const upload = require('./backend/routes/upload-replay');

function readStringAndAdvance(buffer, start, numBytes)
{
    let pos = start
    let string = buffer.subarray(pos, pos+=numBytes);
    return {str : string.toString(), pos : pos};
}

function readUInt16AndAdvance(buffer, start)
{
  let pos = start;
  let t = buffer.subarray(pos, pos+=1);
  let value = t.readInt8(0)
  return {value: value, pos: pos};
}

function readInt8AndAdvance(buffer, start)
{
  let pos = start;
  let t = buffer.subarray(pos, pos+=2);
  let value = t.readUInt16LE(0)
  return {value: value, pos: pos};
}

// route for handling requests from the Angular client 
app.post('/api/upload-replay', upload.single('file'),  (req, res) => {
  let file = req.file;
  console.log("File uploaded: ", req.file);
  fs.readFile(file.path, function(err, buffer)
  {
    buff = new AdvancableBuffer(buffer);
    console.log(buffer)
    let header_magic = buff.readString(3);
    console.log(header_magic);

    let version = buff.readUInt16();
    console.log(version)

    if (version < 5 || version >7 )
    {
      console.log("Unsupported version")
      return;
    }

    let format = buff.readInt8();
    if (format != 66)
    {
      console.log("Unsupported format")
      return;
    }

    let compressionofRefTable = buff.readInt8();

    if (compressionofRefTable != 67 && compressionofRefTable != 85)
    {
      console.log("Unsupported compression format, Ref")
      return;
    }

    let compressionofRefBody = buff.readInt8();
    if (compressionofRefBody != 67 && compressionofRefBody != 85)
    {
      console.log("Unsupported compression format, Body")
      return;
    }

    let unknownByte = '';
    if (version >= 4)
    {
      unknownByte = buff.readString(1);
    }

    let id = buff.readUInt32();
    console.log(id)

    if (version >=6)
    {
      userData = buff.readBytes()
    }

    let numNodes = buff.readUInt32();
  })
}); 
  
app.listen(3000, () => { 
    console.log('Server listening on port 3000'); 
});