text: from app import db
  from app.main import bp
  from flask import render_template, redirect, flash, url_for, request, g, jsonify, current_app
  from app.main.forms import EditProfileForm, PostForm, SearchForm
  from app.translate import translate
  from flask_login import current_user, login_required
  from flask_babel import _, get_locale
  from app.models import User, Post
  from datetime import datetime
  from guess_language import guess_language
  
  
  @bp.route('/', methods=['GET', 'POST'])
  @bp.route('/index', methods=['GET', 'POST'])
  @login_required
  def index():
      form = PostForm()
      if form.validate_on_submit():
          language = guess_language(form.post.data)
          if language == 'UNKNOWN' or len(language) > 5:
              language = ''
          post = Post(body=form.post.data, author=current_user, language=language)
          db.session.add(post)
          db.session.commit()
          flash(_('Your post is now live!'))
          return redirect(url_for('main.index'))
      page = request.args.get('page', 1, type=int)
      posts = current_user.followed_posts().paginate(page, current_app.config['POSTS_PER_PAGE'], False)
      next_url = url_for('main.index', page=posts.next_num) if posts.has_next else None
      prev_url = url_for('main.index', page=posts.prev_num) if posts.has_prev else None
      return render_template('index.html', title=_("Home"), posts=posts.items, form=form, next_url=next_url, prev_url=prev_url)
  
  
  
  
  
  @bp.route('/user/<username>')
  @login_required
  def user(username):
      user = User.query.filter_by(username=username).first_or_404()
      page = request.args.get('page', 1, type=int)
      posts = user.posts.order_by(Post.timestamp.desc()).paginate(
          page, current_app.config['POSTS_PER_PAGE'], False)
      next_url = url_for('main.user', username=user.username, page=posts.next_num) if posts.has_next else None
      prev_url = url_for('main.user', username=user.username, page=posts.prev_num) if posts.has_prev else None
      return render_template('user.html', user=user, posts=posts.items, next_url=next_url, prev_url=prev_url)
  
  @bp.route('/edit_profile', methods=['GET', 'POST'])
  @login_required
  def edit_profile():
      form = EditProfileForm(current_user.username)
      if form.validate_on_submit():
          current_user.username = form.username.data
          current_user.about_me = form.about_me.data 
          db.session.commit()
          flash(_('Your changes have been saved.'))
          return redirect(url_for('main.edit_profile'))
      elif request.method == 'GET':
          form.username.data = current_user.username
          form.about_me.data = current_user.about_me
      return render_template('edit_profile.html', title=_('Edit Profile'), form=form)
  
  @bp.route('/follow/<username>')
  @login_required
  def follow(username):
      user = User.query.filter_by(username=username).first()
      if user is None:
          flash(_('User %(username)s not found.', username=username))
          return redirect(url_for('main.index'))
      if user == current_user:
          flash(_('You cannot follow yourself!'))
          return redirect(url_for('main.user', username=username))
      current_user.follow(user)
      db.session.commit()
      flash(_("You are following %(username)s!", username=username))
      return redirect(url_for('main.user', username=username))
  
  @bp.route('/unfollow/<username>')
  @login_required
  def unfollow(username):
      user = User.query.filter_by(username=username).first()
      if user is None:
          flash(_('User %(username)s not found.', username=username))
          return redirect(url_for('main.index'))
      if user == current_user:
          flash(_('You cannot unfollow yourself!'))
          return redirect(url_for('main.user', username=username))
      current_user.unfollow(user)
      db.session.commit()
      flash(_("You are not following %(username).", username=username))
      return redirect(url_for('main.user', username=username))
  
  @bp.route('/explore')
  @login_required
  def explore():
      page = request.args.get('page', 1, type=int)
      posts = Post.query.order_by(Post.timestamp.desc()).paginate(page, current_app.config["POSTS_PER_PAGE"], False)
      next_url = url_for('main.explore', page=posts.next_num) \
          if posts.has_next else None
      prev_url = url_for('main.explore', page=posts.prev_num) \
          if posts.has_prev else None
      return render_template('index.html', title=_('Explore'), posts=posts.items, next_url=next_url, prev_url=prev_url)
  
  
  @bp.route('/search')
  @login_required
  def search():
      if not g.search_form.validate():
          return redirect(url_for('main.explore'))
      page = request.args.get('page', 1, type=int)
      posts, total = Post.search(g.search_form.q.data, page, current_app.config['POSTS_PER_PAGE'])
      next_url = url_for('main.search', q=g.search_form.q.data, page=page+1) \
          if total > page * current_app.config['POSTS_PER_PAGE'] else None
      prev_url = url_for('main.search', q=g.search_form.q.data, page=page-1) \
          if page > 1 else None
      return render_template('search.html', title=_('Search'), posts=posts, next_url=next_url, prev_url=prev_url)
  
  
  @bp.route('/translate', methods=['POST'])
  @login_required
  def translate_text():
      return jsonify({'text': translate(request.form['text'],
                                        request.form['source_language'],
                                        request.form['dest_language'])})
  
  
  @bp.before_request
  def before_request():
      # current_user comes from user_loader callback so already in db session
      if current_user.is_authenticated:
          current_user.last_seen = datetime.utcnow()
          db.session.commit()
          g.search_form = SearchForm()
      g.locale = str(get_locale())