[models.py]

import datetime

from flask_bcrypt import generate_password_hash
from flask_login import UserMixin
from peewee import *


DATABASE = SqliteDatabase('social.db')


class User(UserMixin, Model):
	username = CharField(unique=True)
	email = CharField(unique=True)
	password = CharField(max_length=100)
	joined_at = DateTimeField(default=datetime.datetime.now)
	is_admin = BooleanField(default=False)

	class Meta:
		database = DATABASE
		order_by = ('-joined_at',)

	@classmethod
	def create_user(cls, username, email, password, admin=False):
		try:
			cls.create(
				username=username,
				email=email,
				password=generate_password_hash(password),
				is_admin=admin
				)
		except IntegrityError:
			raise ValueError("User already exists")

def initialize():
	DATABASE.connect()
	DATABASE.create_tables([User], safe=True)
	DATABASE.close()

[forms.py]

from flask_wtf import Form
from wtforms import StringField, PasswordField
from wtforms.validators import DataRequired, Regexp, ValidationError, Email, Length, EqualTo

from models import User


def name_exists(form, field):
	if User.select().where(User.username == field.data ).exists():
		raise ValidationError('User with that name already exists!')

def email_exists(form, field):
	if User.select().where(User.email == field.data ).exists():
		raise ValidationError('User with that email already exists!')

class RegisterForm(Form):
	username = StringField(
		'Username',
		validators = [
				DataRequired(),
				Regexp(
					r'^[a-zA-Z0-9_]+$', 
					message="Only letters, numbers and underscores are allowedself."
				),
				name_exists
		])
	
	email = StringField(
		'Email',
		validators = [
				DataRequired(),
				Email(),
				email_exists
		])

	password = PasswordField(
		'Password',
		validators = [
				DataRequired(),
				Length(min=2),
				EqualTo('password2', message='Passwords must match!')
		])

	password2 = PasswordField(
		'Confirm Password',
		validators = [DataRequired()]
		)

class LoginForm(Form):
	email = StringField('Email', validators=[DataRequired(), Email()])
	password = PasswordField('Password', validators=[DataRequired()])

[app.py]

from flask import Flask, g, render_template, redirect, url_for, flash
from flask_bcrypt import check_password_hash
from flask_login import LoginManager, login_user, logout_user, login_required

import forms
import models

DEBUG = True
PORT = 8000
HOST = '0.0.0.0'

app = Flask(__name__)
app.secret_key = 'jnkla@sdioa!sdjoo^paud&1293*hoads.ln10'

login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = 'login'

@login_manager.user_loader
def load_user(userID):
	try:
		models.User.get(models.User.id == userID)
	except models.DoesNotExist:
		return None

@app.before_request
def before_request():
    """Connect to the database before each request"""
    g.db = models.DATABASE
    g.db.connect()
    

@app.after_request
def after_request(response):
    """Close the database connection after each request"""
    g.db.close()
    return response

@app.route('/register', methods=['POST', 'GET'])
def register():
	form = forms.RegisterForm()		#Create form instance with validated values
	if form.validate_on_submit(): 	#If all submitted data is valid
		flash("You have been registered successfully!", "success")
		models.User.create_user(
			username=form.username.data, 
			email=form.email.data, 
			password=form.password.data, 
			)
		return redirect(url_for('index'))
	return render_template('register.html', form=form)


@app.route('/login', methods=['GET', 'POST'])
def login():
    form = forms.LoginForm()
    if form.validate_on_submit():
        try:
            user = models.User.get(models.User.email == form.email.data)
        except models.DoesNotExist:
            flash("Your email does not match your password!", "error")
        else:
            if check_password_hash(user.password, form.password.data):
                login_user(user)
                flash("You've been logged in successfully", "success")
                return redirect(url_for('index'))
            else:
                flash("Your email does not match your password!", "error")
    return render_template('login.html', form=form)

@app.route('/logout')
@login_required
def logout():
    logout_user()
    flash("You've successfully logged out", "success")
    return redirect(url_for('index'))

@app.route('/')
def index():
	return "Hey!"


if __name__ == '__main__':
    models.initialize()
    try:
    	models.User.create_user(
    		username='basharghadanfar', 
    		email='10.tens@gmail.com', 
    		password='123456', 
    		admin=True
    	)
    except ValueError:
    	pass
    app.run(debug=DEBUG, port=PORT, host=HOST)

[macros.html]

{% macro render_field(field) %}

<div class="field">
    {{ field(placeholder=field.label.text) }}
    {% if field.errors %}
        {% for error in field.errors %}
        <div class="notification error">{{error}}</div>
        {% endfor %}
    {% endif %}
</div>

{% endmacro %}

[register.html]

{% from 'macros.html' import render_field %}

<form method="POST" action="" class="form">
    {{ form.hidden_tag() }}
    {% for field in form %}
        {{ render_field(field) }}
    {% endfor %}
    <button type="submit" id="submit">Register!</button>
</form>

[login.html]

{% from 'macros.html' import render_field %}

<form method="POST" action="" class="form">
    {{ form.hidden_tag() }}
    {% for field in form %}
        {{ render_field(field) }}
    {% endfor %}
    <button type="submit" id="submit">Login!</button>
</form>