middleware.js

const Blog = require("./models/blog");
const Comment = require("./models/comment");

module.exports.isLoggedIn = (req, res, next) => {
  if (!req.isAuthenticated()) {
    req.session.returnTo = req.originalUrl;
    req.flash("error", "You must be signed in first");
    return res.redirect("/login");
  }
  next();
};

module.exports.isAuthor = async (req, res, next) => {
  const { id } = req.params;
  const blog = await Blog.findById(id);
  if (!blog.author.equals(req.user._id)) {
    req.flash("error", "You do not have permission to do that!");
    return res.redirect(`/blogs/${blog._id}`);
  }
  next();
};

module.exports.isCommentAuthor = async (req, res, next) => {
  const { id, commentId } = req.params;
  const comment = await Comment.findById(commentId);
  if (!comment.author.equals(req.user._id)) {
    req.flash("error", "You do not have permission to do that!");
    return res.redirect(`/blogs/${blog._id}`);
  }
  next();
};