Add 'api.js', Modify 'index.js'

+const SpotifyWebApi = require('spotify-web-api-node'); // spotify api
+//const { search } = require('.');
+var spotifyApi = new SpotifyWebApi({
+    clientId: "faf7865d62b5488da2f6bca05e63a075", //your id
+    clientSecret: "b888f07e8986499aa70950b0235d81eb", //your secret
+    redirectUri: 'http://localhost:3000/callback' //redirectUri
+  });
+
+const scopes = [
+    'ugc-image-upload',
+    'user-read-playback-state',
+    'user-modify-playback-state',
+    'user-read-currently-playing',
+    'streaming',
+    'app-remote-control',
+    'user-read-email',
+    'user-read-private',
+    'playlist-read-collaborative',
+    'playlist-modify-public',
+    'playlist-read-private',
+    'playlist-modify-private',
+    'user-library-modify',
+    'user-library-read',
+    'user-top-read',
+    'user-read-playback-position',
+    'user-read-recently-played',
+    'user-follow-read',
+    'user-follow-modify'
+  ];
+
+var access_token;
+
+function redirect(res){
+    res.redirect(spotifyApi.createAuthorizeURL(scopes));
+}
+module.exports.redirect = redirect;
+
+
+function callback(req, res) {
+    const error = req.query.error;
+    const code = req.query.code;
+    const state = req.query.state;
+  
+    if (error) {
+      console.error('Callback Error:', error);
+      res.send(`Callback Error: ${error}`);
+      return;
+    }
+  
+    spotifyApi
+      .authorizationCodeGrant(code)
+      .then(data => {
+        access_token = data.body['access_token'];
+        const refresh_token = data.body['refresh_token'];
+        const expires_in = data.body['expires_in'];
+  
+        spotifyApi.setAccessToken(access_token);
+        spotifyApi.setRefreshToken(refresh_token);
+  
+        console.log('access_token:', access_token);
+        console.log('refresh_token:', refresh_token);
+  
+        console.log(
+          `Sucessfully retreived access token. Expires in ${expires_in} s.`
+        );
+
+        setInterval(async () => {
+          const data = await spotifyApi.refreshAccessToken();
+          const access_token = data.body['access_token'];
+  
+          console.log('The access token has been refreshed!');
+          console.log('access_token:', access_token);
+          spotifyApi.setAccessToken(access_token);
+        }, expires_in / 2 * 1000);
+      })
+      .catch(error => {
+        console.error('Error getting Tokens:', error);
+        res.send(`Error getting Tokens: ${error}`);
+    });
+	
+}
+module.exports.callback = callback;
+
+
+// Search artists whose name, album or artist contains 'hip hop'
+function searchArtists(genre, callback){
+  spotifyApi.searchArtists(genre)
+  .then(function(data) {
+    console.log('Search artists success', data.body.artists.items);
+    callback(data.body.artists.items[19].id)
+  }, function(err) {
+    console.error(err);
+  });
+}
+module.exports.searchArtists = searchArtists;
+
+// Get an artist
+function getArtist(artistid,callback){
+  spotifyApi.getArtist(artistid)
+  .then(function(data) {
+    console.log('getArtist success', data.body);
+    callback(data.body);
+  }, function(err) {
+    console.error(err);
+  });
+}
+module.exports.getArtist = getArtist;
+//followers.total
+//images[0]
+//name
+//popularity
+//id
+// Get albums by a certain artist
+
+function getArtistAlbums(artistid,callback){
+  spotifyApi.getArtistAlbums(artistid)
+  .then(function(data) {
+    console.log('getArtistAlbums success', data.body.items[0].id);
+    callback(data.body.items[0].id);
+  }, function(err) {
+    console.error(err);
+  });
+}
+module.exports.getArtistAlbums = getArtistAlbums;
+
+
+// function search(){
+//   SearchUrl = `https://open.spotify.com/artist/4kyWODlwZxF4tiAe4LblhX`
+//   request(SearchUrl, (error, response, body) => {
+//     var data = body;
+//     console.log(body)
+//     // for (var j = 0; j < 10; j++) {
+//     //   var team_id = data["info"]["participants"][j]["teamId"]
+//     //   if (p_id == summoner_puuid) {
+//     //       my_info["kills"] += match["info"]["participants"][j]["kills"]
+//     //       win = match["info"]["participants"][j]["win"];
+//     //   }
+//     // }
+//   })
+// }
+// module.exports.search = search;
+// var item = data.body.artists.items.find((item,idx)=>{
+    //   item.popularity == "0";
+    // });
\ No newline at end of file

 const express = require("express");
+const { nextTick } = require("process");
 const router = express.Router();
+var api = require('./api');
 
-router.get('/', (req, res) => res.render('index'));
-router.get("/login", (req, res) => res.render("login", {page: "login"}));
-router.get("/signup", (req, res) => res.render("signup", {page: "signup"}));
+router.get('/', (req, res) => {
+    api.redirect(res);
+  });
+
+router.get('/callback', (req, res) => {
+    api.callback(req,res);
+    res.render('index');
+});
+
+router.get("/select", (req, res) => { 
+    res.render("select", {page: "select"})
+});
+
+router.get("/rock", (req, res) => {
+  var genre = 'rock';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("rock", {artistdata: artistdata});
+    });
+  }); 
+});
+router.get("/electronic", (req, res) => {
+  var genre = 'electronic';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("electronic", {artistdata: artistdata});
+    });
+  }); 
+});
+router.get("/hiphop", (req, res) => {
+  var genre = 'hiphop';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("hiphop", {artistdata: artistdata});
+    });
+  }); 
+});
+router.get("/acoustic", (req, res) => {
+  var genre = 'acoustic';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("acoustic", {artistdata: artistdata});
+    });
+  }); 
+});
+router.get("/jazz", (req, res) => {
+  var genre = 'jazz';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("jazz", {artistdata: artistdata});
+    });
+  }); 
+});
+router.get("/pop", (req, res) => {
+  var genre = 'pop';
+  api.searchArtists(genre,function(artistid){
+    api.getArtist(artistid,function(artistdata){
+      res.render("pop", {artistdata: artistdata});
+    });
+  }); 
+});
 
 module.exports = router;