import dateutil.parser
import datetime
from werkzeug.security import generate_password_hash, check_password_hash
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer

from flask import current_app

from flask_login import UserMixin

from . import db
from . import login_manager


class Role(db.Model):
    __tablename__ = 'roles'
    
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64), unique=True)
    users = db.relationship('User', backref='role', lazy='dynamic')

    def __repr__(self):
        return '<Role %r>' % self.name


class User(UserMixin, db.Model):
    __tablename__ = 'users'
    
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(128), unique=True, index=True)
    username = db.Column(db.String(64), unique=True, index=True)
    password_hash = db.Column(db.String(128))
    full_name = db.Column(db.String(255), index=True)
    avatar = db.Column(db.String(255), index=True)
    created_at = db.Column(db.DateTime)
    role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))
    confirmed = db.Column(db.Boolean, default=False)
    
    @property
    def password(self):
        raise AttributeError('password is not a readable attribute')

    @password.setter
    def password(self, password):
        self.password_hash = generate_password_hash(password)

    def verify_password(self, password):
        return check_password_hash(self.password_hash, password)
    
    # generates confirmation token for user email confirmation
    def generate_confirmation_token(self, expiration=3600):
        s = Serializer(current_app.config['SECRET_KEY'], expiration)
        return s.dumps({'confirm': self.id})
    
    # confirms user email by id
    def confirm(self, token):
        s = Serializer(current_app.config['SECRET_KEY'])
        try:
            data = s.loads(token)
        except:
            return False
        if data.get('confirm') != self.id:
            return False
        self.confirmed = True
        db.session.add(self)
        return True
    
    # generates token for password reset
    def generate_reset_token(self, expiration=3600):
        s = Serializer(current_app.config['SECRET_KEY'], expiration)
        return s.dumps({'reset': self.id})
        
    def reset_password(self, token, new_password):
        s = Serializer(current_app.config['SECRET_KEY'])
        try:
            data = s.loads(token)
        except:
            return False
        if data.get('reset') != self.id:
            return False
        self.password = new_password
        db.session.add(self)
        return True
    
    def __repr__(self):
        return '<User %r>' % self.username

@login_manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))