from flask import render_template, redirect, url_for, flash, request, current_app, jsonify, session
from flask_login import login_user, logout_user, login_required, current_user
from urllib.parse import urlparse
from app import db
from app.models import User
from app.routes import auth_bp
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, BooleanField, SubmitField
from wtforms.validators import DataRequired, Length, EqualTo, ValidationError
from werkzeug.exceptions import BadRequest

# Login form
class LoginForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired()])
    password = PasswordField('Password', validators=[DataRequired()])
    remember_me = BooleanField('Remember Me')
    submit = SubmitField('Sign In')

# Registration form
class RegistrationForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired(), Length(min=3, max=64)])
    password = PasswordField('Password', validators=[DataRequired(), Length(min=8)])
    password2 = PasswordField('Confirm Password', validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Register')

    def validate_username(self, username):
        user = User.query.filter_by(username=username.data).first()
        if user is not None:
            raise ValidationError('Please use a different username.')

@auth_bp.route('/login', methods=['GET', 'POST'])
def login():
    if current_user.is_authenticated:
        return redirect(url_for('dashboard.index'))
    
    form = LoginForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.username.data).first()
        
        if user is None or not user.check_password(form.password.data):
            flash('Invalid username or password', 'error')
            return redirect(url_for('auth.login'))
        
        login_user(user, remember=form.remember_me.data)
        
        next_page = request.args.get('next')
        if not next_page or urlparse(next_page).netloc != '':
            next_page = url_for('dashboard.index')
            
        return redirect(next_page)
    
    return render_template('auth/login.html', title='Sign In', form=form)

@auth_bp.route('/logout')
@login_required
def logout():
    logout_user()
    flash('You have been logged out', 'info')
    return redirect(url_for('auth.login'))

@auth_bp.route('/register', methods=['GET', 'POST'])
def register():
    if current_user.is_authenticated:
        return redirect(url_for('dashboard.index'))
    
    form = RegistrationForm()
    if form.validate_on_submit():
        user = User(username=form.username.data)
        user.set_password(form.password.data)
        db.session.add(user)
        db.session.commit()
        flash('Registration successful! You can now log in.', 'success')
        return redirect(url_for('auth.login'))
    
    return render_template('auth/register.html', title='Register', form=form)

@auth_bp.route('/update_profile', methods=['POST'])
@login_required
def update_profile():
    """Update user profile information"""
    username = request.form.get('username')
    
    if not username or username.strip() == '':
        flash('Username cannot be empty', 'error')
        return redirect(url_for('auth.profile'))
    
    # Check if username is already taken by another user
    existing_user = User.query.filter(User.username == username, User.id != current_user.id).first()
    if existing_user:
        flash('Username is already taken', 'error')
        return redirect(url_for('auth.profile'))
    
    # Update username
    current_user.username = username
    db.session.commit()
    flash('Profile updated successfully', 'success')
    return redirect(url_for('auth.profile'))

@auth_bp.route('/change_password', methods=['POST'])
@login_required
def change_password():
    """Change user password"""
    current_password = request.form.get('current_password')
    new_password = request.form.get('new_password')
    confirm_password = request.form.get('confirm_password')
    
    # Validate input
    if not all([current_password, new_password, confirm_password]):
        flash('All fields are required', 'error')
        return redirect(url_for('auth.profile'))
    
    if new_password != confirm_password:
        flash('New passwords do not match', 'error')
        return redirect(url_for('auth.profile'))
    
    # Check current password
    if not current_user.check_password(current_password):
        flash('Current password is incorrect', 'error')
        return redirect(url_for('auth.profile'))
    
    # Set new password
    current_user.set_password(new_password)
    db.session.commit()
    flash('Password changed successfully', 'success')
    return redirect(url_for('auth.profile'))

@auth_bp.route('/update_preferences', methods=['POST'])
@login_required
def update_preferences():
    """Update user preferences like theme"""
    theme_preference = request.form.get('theme_preference', 'system')
    
    # Store in session for now, but could be added to user model
    session['theme_preference'] = theme_preference
    
    flash('Preferences updated successfully', 'success')
    return redirect(url_for('auth.profile'))

@auth_bp.route('/profile')
@login_required
def profile():
    # Get theme preference from session or default to system
    theme_preference = session.get('theme_preference', 'system')
    
    return render_template('auth/profile.html', 
                          title='User Profile',
                          theme_preference=theme_preference)