app.js:

const express = require("express");
const fs = require("fs");
const session = require("express-session");
const fileUpload = require("express-fileupload");
const app = express();


app.set("view engine", "ejs");
app.use(express.static("public"));
app.use(express.urlencoded({ extended: true }));
app.use(fileUpload());
app.use(session({
  secret: "mysecretkey",
  resave: false,
  saveUninitialized: false
}));

const predefinedGenres = ['Rock', 'Pop', 'Jazz', 'Hip Hop', 'Electronic', 'Blues'];

function getMusicianById(id) {
  const data = fs.readFileSync("./db/musicians.json");
  const musicians = JSON.parse(data);

  return musicians.musicians.find(musician => musician.id === id);
}

function requireLogin(req, res, next) {
  if (req.session.musicianId) {
    next();
  } else {
    res.redirect("/login");
  }
}

function search(query) {
  const data = fs.readFileSync('./db/musicians.json');
  const musicians = JSON.parse(data).musicians.map(musician => {
    return {
      name: musician.name,
      genre: musician.genre,
      originalName: musician.name,
      profileLink: `/profile/${musician.id}`,
      thumbnail: musician.thumbnail,
      soundcloud: musician.soundcloud
    };
  });
  let results = musicians;
  if (query) {
    const lowerQuery = query.toLowerCase();
    results = musicians.filter(musician => {
      const nameScore = musician.name.toLowerCase().startsWith(lowerQuery) ? 2 : musician.name.toLowerCase().includes(lowerQuery) ? 1 : 0;
      const genreScore = musician.genre.toLowerCase().startsWith(lowerQuery) ? 2 : musician.genre.toLowerCase().includes(lowerQuery) ? 1 : 0;
      return nameScore + genreScore > 0;
    }).sort((a, b) => {
      const aNameScore = a.name.toLowerCase().startsWith(lowerQuery) ? 2 : a.name.toLowerCase().includes(lowerQuery) ? 1 : 0;
      const bNameScore = b.name.toLowerCase().startsWith(lowerQuery) ? 2 : b.name.toLowerCase().includes(lowerQuery) ? 1 : 0;
      const aGenreScore = a.genre.toLowerCase().startsWith(lowerQuery) ? 2 : a.genre.toLowerCase().includes(lowerQuery) ? 1 : 0;
      const bGenreScore = b.genre.toLowerCase().startsWith(lowerQuery) ? 2 : b.genre.toLowerCase().includes(lowerQuery) ? 1 : 0;
      return (bNameScore + bGenreScore) - (aNameScore + aGenreScore);
    });
  }
  return results;
}

app.use((req, res, next) => {
  if (req.session.musicianId) {
    const musician = getMusicianById(req.session.musicianId);
    res.locals.musician = musician;
    res.locals.userLoggedIn = true;
    res.locals.username = musician.name;
  } else {
    res.locals.userLoggedIn = false;
  }

  next();
});

app.get("/", (req, res) => {
  const data = fs.readFileSync("./db/musicians.json");
  const musicians = JSON.parse(data);

  res.render("index", { musicians: musicians.musicians });
});

app.get("/register", (req, res) => {
  if (req.session.musicianId) {
    const musician = getMusicianById(req.session.musicianId);
    res.redirect("/profile/" + musician.id);
  } else {
    res.render("register");
  }
});

app.post("/register", (req, res) => {
  if (req.session.musicianId) {
    const musician = getMusicianById(req.session.musicianId);
    res.redirect("/profile/" + musician.id);
  } else {
    const data = fs.readFileSync("./db/musicians.json");
    const musicians = JSON.parse(data);

    const newMusician = {
      id: musicians.musicians.length + 1,
      name: req.body.name,
      genre: req.body.genre,
      instrument: req.body.instrument,
      soundcloud: req.body.soundcloud,
      password: req.body.password,
      location: req.body.location,
      login: req.body.login
    };

    if (req.files && req.files.thumbnail) {
      const file = req.files.thumbnail;
      const filename = "musician_" + newMusician.id + "_" + file.name;
      file.mv("./public/img/" + filename);

      newMusician.thumbnail = filename;
    }

    musicians.musicians.push(newMusician);
    fs.writeFileSync("./db/musicians.json", JSON.stringify(musicians));

    req.session.musicianId = newMusician.id;
    res.redirect("/profile/" + newMusician.id);
  }
});

app.get("/profile/:id", (req, res) => {
  const musician = getMusicianById(parseInt(req.params.id));

  if (musician) {
    res.render("profile", { musician: musician });
  } else {
    res.status(404).send("Musician not found");
  }
});

app.get("/login", (req, res) => {
  res.render("login");
});

app.post("/login", (req, res) => {
  const data = fs.readFileSync("./db/musicians.json");
  const musicians = JSON.parse(data);

  const musician = musicians.musicians.find(musician => musician.login === req.body.login && musician.password === req.body.password);

  if (musician) {
    req.session.musicianId = musician.id;
    res.redirect("/profile/" + musician.id);

  } else {
    res.render("login", { error: "Invalid login or password" });
  }
});

app.get("/logout", (req, res) => {
  req.session.destroy();
  res.redirect("/");
});

app.get('/search', (req, res) => {
const query = req.query.query || '';
const musicians = search(query);
res.locals.predefinedGenres = predefinedGenres;
res.render('search', { musicians, query });
});

app.get("/profile/:id/edit", requireLogin, (req, res) => {
  const musician = getMusicianById(parseInt(req.params.id));

  if (musician) {
    if (req.session.musicianId === musician.id) { // Check if the logged-in user is the owner of the profile
      res.render("edit-profile", { musician: musician });
    } else {
      res.status(403).send("Access denied");
    }
  } else {
    res.status(404).send("Musician not found");
  }
});





app.post('/profile/:id/edit', requireLogin, (req, res) => {
  const musician = getMusicianById(parseInt(req.params.id));

  if (musician) {
    if (!req.body.name || !req.body.genre) {
      res.status(400).send('Please fill out all fields');
    
    } else {
      musician.name = req.body.name;
      musician.genre = req.body.genre;
      musician.instrument = req.body.instrument;
      musician.soundcloud = req.body.soundcloud;
      musician.location = req.body.location;
      musician.bio = req.body.bio;

      if (req.files && req.files.thumbnail) {
        const file = req.files.thumbnail;
        const filename = 'musician_' + musician.id + '_' + file.name;
        file.mv('./public/img/' + filename);
        musician.thumbnail = filename;
      }

      const data = fs.readFileSync('./db/musicians.json');
      const musicians = JSON.parse(data);
      const index = musicians.musicians.findIndex(m => m.id === musician.id);
      musicians.musicians[index] = musician;

      fs.writeFileSync('./db/musicians.json', JSON.stringify(musicians));

      res.redirect('/profile/' + musician.id);
    }
  } else {
    res.status(404).send('Musician not found');
  }
});

function isValidSoundCloudUrl(url) {
  return url.startsWith('https://soundcloud.com/');
}

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

profile.ejs:
<!DOCTYPE html>
<html>
  <head>
    <title><%= musician.name %> - Musician Profile</title>
  </head>
  <body>
    <img src="/img/<%= musician.thumbnail %>" alt="<%= musician.name %>">
    <h1><%= musician.name %></h1>
    <p><strong>Genre:</strong> <%= musician.genre %></p>
    <p><strong>Instrument:</strong> <%= musician.instrument %></p>
    <p><strong>Location:</strong> <%= musician.location %></p>
    <p><strong>Bio:</strong> <%= musician.bio %></p>
    <iframe width="100%" height="300" scrolling="no" frameborder="no" src="<%= musician.soundcloud %>"></iframe>
    <a href="/profile/<%= musician.id %>/edit">Edit profile</a>

    <div id="edit-profile-modal" class="modal">
      <div class="modal-content">
        <span class="close">&times;</span>
        <h2>Edit Profile</h2>
        <form action="/profile/<%= musician.id %>/edit" method="POST" enctype="multipart/form-data">
          <div>
            <label for="name">Name:</label>
            <input type="text" id="name" name="name" value="<%= musician.name %>">
          </div>
          <div>
            <label for="genre">Genre:</label>
            <input type="text" id="genre" name="genre" value="<%= musician.genre %>">
          </div>
          <div>
            <label for="instrument">Instrument:</label>
            <input type="text" id="instrument" name="instrument" value="<%= musician.instrument %>">
          </div>
          <div>
            <label for="location">Location:</label>
            <input type="text" id="location" name="location" value="<%= musician.location %>">
          </div>
          <div>
            <label for="bio">Bio:</label>
            <textarea id="bio" name="bio"><%= musician.bio %></textarea>
          </div>
          <div>
            <label for="soundcloud">SoundCloud:</label>
            <input type="text" id="soundcloud" name="soundcloud" value="<%= musician.soundcloud %>">
          </div>
          <div>
            <label for="thumbnail">Thumbnail:</label>
            <input type="file" id="thumbnail" name="thumbnail">
          </div>
          <button type="submit">Save</button>
        </form>
      </div>
    </div>

    <script>
      const modal = document.getElementById("edit-profile-modal");
      const btn = document.getElementsByTagName("a")[0];
      const span = document.getElementsByClassName("close")[0];

      btn.onclick = function() {
        modal.style.display = "block";
      }

      span.onclick = function() {
        modal.style.display = "none";
      }

      window.onclick = function(event) {
        if (event.target == modal) {
          modal.style.display = "none";
        }
      }
    </script>
  </body>
</html>
надо проверить, залогинен ли пользователь, перед тем как дать ему возможность редактировать профиль. В данный момент я под логином разных пользователей могу редактировать их профили. надо скрывать форму для редактирования для других пользователей