rangevote/rangevote.js

var express = require('express')
var bodyParser = require('body-parser')
var fs=require('fs')
var hashindex=require('hash-index')
var fc=require("./filechunker.js");

var app = express()

var TemplateVoteRange=new fc("./rangevote.html");
var TemplateVotePlur =new fc("./plurvote.html");

var Candidates=[
    "Chris Christie",
    "Donald Trump",
    "Mike Pence",
    "Nikki Haley",
    "Ron DeSantis",
    "Tim Scott",
    "Vivek Ramaswamy",
];

function CanId(c)
{
    let w=c.split(" ");
    let lastname=w[w.length-1].toLowerCase();
    let id=lastname.split("-");
    let rval=id[id.length-1];
    return(rval);
}



// Set up data structures for Range Votes and Plur Votes
var Experiment;

fs.readFile('./rangevote.json', 'utf8', (err, data) => {
    if (err) {
        Experiment={};
        Experiment.RangeVotes=new Map();
        Experiment.RangePower=new Map();
        Experiment.RangeResult=new Map();
        Experiment.PlurVotes=new Map();
        Experiment.PlurResult=new Map();
        Experiment.PlurCount=0;
    }
    else Experiment=JSON.parse(data,MapReviver);
    for (let c of Candidates)
    {
        let k=CanId(c);
        let v=Experiment.RangePower.get(k);
        if (typeof(v)!='number' || v==NaN || v==Infinity) Experiment.RangePower.set(k,0);
        v=Experiment.RangeResult.get(k);
        if (typeof(v)!='number' || v==NaN || v==Infinity) Experiment.RangeResult.set(k,0);
        v=Experiment.PlurResult.get(k);
        if (typeof(v)!='number' || v==NaN || v==Infinity) Experiment.PlurResult.set(k,0);
    }
})


function LogErr(err)
{
    if (err) console.log(err);
}

function MapReplacer(key, value) {
  if(value instanceof Map) {
    return {
      dataType: 'Map',
      value: Array.from(value.entries()), // or with spread: value: [...value]
    };
  } else {
    return value;
  }
}

function MapReviver(key, value) {
  if(typeof value === 'object' && value !== null) {
    if (value.dataType === 'Map') {
      return new Map(value.value);
    }
  }
  return value;
}

function Persist()
{
    var str=JSON.stringify(Experiment,MapReplacer);
    fs.writeFile("./rangevote.json",str,LogErr);
}



// Construct the static page for range voting
var RangeHTML="";
for (let c of Candidates)
{
    RangeHTML=RangeHTML+'      <tr>'+
	'          <td>'+c+'</td><td><input style="width:95%" type="range" min="-1" max="100" value="-1" id="i-'+CanId(c)+'" name="n-'+CanId(c)+'" /></td><td><span id="o-'+CanId(c)+'">No Opinion</span></td></tr>\n';
}
RangeHTML=TemplateVoteRange.Chunks[0]+RangeHTML+TemplateVoteRange.Chunks[1];


// Construct the static page for Plurality Voting
var PlurHTML="";
for (let c of Candidates)
{
    PlurHTML=PlurHTML+'      <tr>'+
	'          <td><input type="radio" value="v-'+CanId(c)+'" name="pick" /></td><td>'+c+'</td></tr>\n';
}
PlurHTML=TemplateVotePlur.Chunks[0]+PlurHTML+TemplateVotePlur.Chunks[1];


// create application/json parser
var jsonParser = bodyParser.json()

// create application/x-www-form-urlencoded parser
var urlencodedParser = bodyParser.urlencoded({ extended: false })

app.get('/', (req, res) => {
let kind=hashindex(req.socket.remoteAddress+"saltA",2);
if (kind==0) res.send(RangeHTML);
else         res.send(PlurHTML);
})

function lerp(a,b,c,d,e)
{
    if (a<b) a=b;
    if (a>c) a=c;
    let rval=d+(a-b)*(e-d)/(c-b);
    return(rval);
}


function PlurVote(ip,NewChoice)
{
    let OldChoice=Experiment.PlurVotes.get(ip);
    if (typeof(OldChoice)=='string') { Experiment.PlurResult.set(OldChoice,Experiment.PlurResult.get(OldChoice)-1); Experiment.PlurCount-=1; }
    if (!NewChoice) return;
    NewChoice=CanId(NewChoice);
    if (typeof(NewChoice)=='string') { Experiment.PlurResult.set(NewChoice,Experiment.PlurResult.get(NewChoice)+1); Experiment.PlurCount+=1; }
    Experiment.PlurVotes.set(ip,NewChoice);
    console.log(Experiment);
}


function AddToRangeResult(vote,mult=1)
{
    for (let[key,val] of vote) if (key) if (val>=0)
    {
	Experiment.RangeResult.set(key,Experiment.RangeResult.get(key)+val*mult);
	Experiment.RangePower.set(key,Experiment.RangePower.get(key)+mult);
    }
}




function RangeVote(ip,entries)
{
    let r0=null,r1=null;
    for (let [key,val] of entries) if (typeof(key)=="string" && val>=0)
    {
        if (r0==null) { r0=val; r1=val; }
	r0=Math.min(r0,val);
	r1=Math.max(r1,val);
    }
    if (r1<=r0) return;
    let NewVote=new Map()
    for (let [key,val] of entries) if (typeof(key)=="string")
    {
	let id=CanId(key);
	let norm=Math.round(lerp(val,r0,r1,0,100));
	if (val>=0) NewVote.set(id,norm);
    }
    let OldVote=Experiment.RangeVotes.get(ip);
    if (OldVote) AddToRangeResult(OldVote,-1);
    Experiment.RangeVotes.set(ip,NewVote);
    AddToRangeResult(NewVote,1);
}


// POST /login gets urlencoded bodies
app.post('/range_vote', urlencodedParser, function (req, res) {
    RangeVote(req.socket.remoteAddress,Object.entries(req.body));
    let str="Results from "+Experiment.RangeVotes.size+" Voters:<br>";
    for (let c of Candidates)
    {
	let key=CanId(c);
	if (Experiment.RangePower.get(key)>0) str=str+c+': '+Math.round(Experiment.RangeResult.get(key)/Experiment.RangePower.get(key))+'% ('+Experiment.RangePower.get(key)+' Voters)<br>';
    }
    Persist();
    res.send(str);
})

app.post('/plur_vote', urlencodedParser, function (req, res) {
    PlurVote(req.socket.remoteAddress,req.body.pick);
    let str="Results from "+Experiment.PlurVotes.size+" Voters:<br>";
    for (let c of Candidates)
    {
	let key=CanId(c);
	if (Experiment.PlurResult.get(key)>0) str=str+c+': '+Math.round(100.0*Experiment.PlurResult.get(key)/Experiment.PlurCount)+'%<br>';
    }
    Persist();
    res.send(str);
})


app.listen(3000,function(req,res) { console.log("Listening for connections"); })