text: from flask import flash, redirect, render_template, request, url_for
  from flask_login import (current_user, login_required, login_user, logout_user)
  from flask_rq import get_queue
  
  from . import account
  from .. import db
  from ..email import send_email
  from ..models import User
  from .forms import (ChangeEmailForm, ChangePasswordForm, CreatePasswordForm,
                      LoginForm, RegistrationForm, RequestResetPasswordForm,
                      ResetPasswordForm)
  
  
  @account.route('/login', methods=['GET', 'POST'])
  def login():
      """Log in an existing user."""
      form = LoginForm()
      if form.validate_on_submit():
          user = User.query.filter_by(email=form.email.data).first()
          if user is not None and user.password_hash is not None and \
                  user.verify_password(form.password.data):
              login_user(user, form.remember_me.data)
              flash('You are now logged in. Welcome back!', 'success')
              return redirect(request.args.get('next') or url_for('main.index'))
          else:
              flash('Invalid email or password.', 'form-error')
      return render_template('account/login.html', form=form)
  
  
  @account.route('/register', methods=['GET', 'POST'])
  def register():
      """Register a new user, and send them a confirmation email."""
      form = RegistrationForm()
      if form.validate_on_submit():
          user = User(
              first_name=form.first_name.data,
              last_name=form.last_name.data,
              email=form.email.data,
              password=form.password.data)
          db.session.add(user)
          db.session.commit()
          token = user.generate_confirmation_token()
          confirm_link = url_for('account.confirm', token=token, _external=True)
          get_queue().enqueue(
              send_email,
              recipient=user.email,
              subject='Confirm Your Account',
              template='account/email/confirm',
              user=user,
              confirm_link=confirm_link)
          flash('A confirmation link has been sent to {}.'.format(user.email),
                'warning')
          return redirect(url_for('main.index'))
      return render_template('account/register.html', form=form)
  
  
  @account.route('/logout')
  @login_required
  def logout():
      logout_user()
      flash('You have been logged out.', 'info')
      return redirect(url_for('main.index'))
  
  
  @account.route('/manage', methods=['GET', 'POST'])
  @account.route('/manage/info', methods=['GET', 'POST'])
  @login_required
  def manage():
      """Display a user's account information."""
      return render_template('account/manage.html', user=current_user, form=None)
  
  
  @account.route('/reset-password', methods=['GET', 'POST'])
  def reset_password_request():
      """Respond to existing user's request to reset their password."""
      if not current_user.is_anonymous:
          return redirect(url_for('main.index'))
      form = RequestResetPasswordForm()
      if form.validate_on_submit():
          user = User.query.filter_by(email=form.email.data).first()
          if user:
              token = user.generate_password_reset_token()
              reset_link = url_for(
                  'account.reset_password', token=token, _external=True)
              get_queue().enqueue(
                  send_email,
                  recipient=user.email,
                  subject='Reset Your Password',
                  template='account/email/reset_password',
                  user=user,
                  reset_link=reset_link,
                  next=request.args.get('next'))
          flash('A password reset link has been sent to {}.'.format(
              form.email.data), 'warning')
          return redirect(url_for('account.login'))
      return render_template('account/reset_password.html', form=form)
  
  
  @account.route('/reset-password/<token>', methods=['GET', 'POST'])
  def reset_password(token):
      """Reset an existing user's password."""
      if not current_user.is_anonymous:
          return redirect(url_for('main.index'))
      form = ResetPasswordForm()
      if form.validate_on_submit():
          user = User.query.filter_by(email=form.email.data).first()
          if user is None:
              flash('Invalid email address.', 'form-error')
              return redirect(url_for('main.index'))
          if user.reset_password(token, form.new_password.data):
              flash('Your password has been updated.', 'form-success')
              return redirect(url_for('account.login'))
          else:
              flash('The password reset link is invalid or has expired.',
                    'form-error')
              return redirect(url_for('main.index'))
      return render_template('account/reset_password.html', form=form)
  
  
  @account.route('/manage/change-password', methods=['GET', 'POST'])
  @login_required
  def change_password():
      """Change an existing user's password."""
      form = ChangePasswordForm()
      if form.validate_on_submit():
          if current_user.verify_password(form.old_password.data):
              current_user.password = form.new_password.data
              db.session.add(current_user)
              db.session.commit()
              flash('Your password has been updated.', 'form-success')
              return redirect(url_for('main.index'))
          else:
              flash('Original password is invalid.', 'form-error')
      return render_template('account/manage.html', form=form)
  
  
  @account.route('/manage/change-email', methods=['GET', 'POST'])
  @login_required
  def change_email_request():
      """Respond to existing user's request to change their email."""
      form = ChangeEmailForm()
      if form.validate_on_submit():
          if current_user.verify_password(form.password.data):
              new_email = form.email.data
              token = current_user.generate_email_change_token(new_email)
              change_email_link = url_for(
                  'account.change_email', token=token, _external=True)
              get_queue().enqueue(
                  send_email,
                  recipient=new_email,
                  subject='Confirm Your New Email',
                  template='account/email/change_email',
                  # current_user is a LocalProxy, we want the underlying user
                  # object
                  user=current_user._get_current_object(),
                  change_email_link=change_email_link)
              flash('A confirmation link has been sent to {}.'.format(new_email),
                    'warning')
              return redirect(url_for('main.index'))
          else:
              flash('Invalid email or password.', 'form-error')
      return render_template('account/manage.html', form=form)
  
  
  @account.route('/manage/change-email/<token>', methods=['GET', 'POST'])
  @login_required
  def change_email(token):
      """Change existing user's email with provided token."""
      if current_user.change_email(token):
          flash('Your email address has been updated.', 'success')
      else:
          flash('The confirmation link is invalid or has expired.', 'error')
      return redirect(url_for('main.index'))
  
  
  @account.route('/confirm-account')
  @login_required
  def confirm_request():
      """Respond to new user's request to confirm their account."""
      token = current_user.generate_confirmation_token()
      confirm_link = url_for('account.confirm', token=token, _external=True)
      get_queue().enqueue(
          send_email,
          recipient=current_user.email,
          subject='Confirm Your Account',
          template='account/email/confirm',
          # current_user is a LocalProxy, we want the underlying user object
          user=current_user._get_current_object(),
          confirm_link=confirm_link)
      flash('A new confirmation link has been sent to {}.'.format(
          current_user.email), 'warning')
      return redirect(url_for('main.index'))
  
  
  @account.route('/confirm-account/<token>')
  @login_required
  def confirm(token):
      """Confirm new user's account with provided token."""
      if current_user.confirmed:
          return redirect(url_for('main.index'))
      if current_user.confirm_account(token):
          flash('Your account has been confirmed.', 'success')
      else:
          flash('The confirmation link is invalid or has expired.', 'error')
      return redirect(url_for('main.index'))
  
  
  @account.route(
      '/join-from-invite/<int:user_id>/<token>', methods=['GET', 'POST'])
  def join_from_invite(user_id, token):
      """
      Confirm new user's account with provided token and prompt them to set
      a password.
      """
      if current_user is not None and current_user.is_authenticated:
          flash('You are already logged in.', 'error')
          return redirect(url_for('main.index'))
  
      new_user = User.query.get(user_id)
      if new_user is None:
          return redirect(404)
  
      if new_user.password_hash is not None:
          flash('You have already joined.', 'error')
          return redirect(url_for('main.index'))
  
      if new_user.confirm_account(token):
          form = CreatePasswordForm()
          if form.validate_on_submit():
              new_user.password = form.password.data
              db.session.add(new_user)
              db.session.commit()
              flash('Your password has been set. After you log in, you can '
                    'go to the "Your Account" page to review your account '
                    'information and settings.', 'success')
              return redirect(url_for('account.login'))
          return render_template('account/join_invite.html', form=form)
      else:
          flash('The confirmation link is invalid or has expired. Another '
                'invite email with a new link has been sent to you.', 'error')
          token = new_user.generate_confirmation_token()
          invite_link = url_for(
              'account.join_from_invite',
              user_id=user_id,
              token=token,
              _external=True)
          get_queue().enqueue(
              send_email,
              recipient=new_user.email,
              subject='You Are Invited To Join',
              template='account/email/invite',
              user=new_user,
              invite_link=invite_link)
      return redirect(url_for('main.index'))
  
  
  @account.before_app_request
  def before_request():
      """Force user to confirm email before accessing login-required routes."""
      if current_user.is_authenticated \
              and not current_user.confirmed \
              and request.endpoint[:8] != 'account.' \
              and request.endpoint != 'static':
          return redirect(url_for('account.unconfirmed'))
  
  
  @account.route('/unconfirmed')
  def unconfirmed():
      """Catch users with unconfirmed emails."""
      if current_user.is_anonymous or current_user.confirmed:
          return redirect(url_for('main.index'))
      return render_template('account/unconfirmed.html')
  