from flask import Blueprint, render_template, request, redirect, url_for, flash
from flask_login import login_user, logout_user, login_required, current_user
from werkzeug.security import check_password_hash
from app.models import User, db
from app.forms import LoginForm, RegisterForm, ForgotPasswordForm
import re

auth = Blueprint('auth', __name__)

@auth.route('/login', methods=['GET', 'POST'])
def login():
    """User login page"""
    if current_user.is_authenticated:
        return redirect(url_for('main.index'))
    
    form = LoginForm()
    if form.validate_on_submit():
        user = User.query.filter_by(email=form.email.data).first()
        
        if user and user.check_password(form.password.data):
            login_user(user, remember=form.remember_me.data)
            next_page = request.args.get('next')
            if not next_page or not next_page.startswith('/'):
                next_page = url_for('community.index')
            flash(f'Welcome back, {user.nickname}!', 'success')
            return redirect(next_page)
        else:
            flash('Invalid email or password.', 'error')
    
    return render_template('auth/login.html', form=form)

@auth.route('/register', methods=['GET', 'POST'])
def register():
    """User registration page"""
    if current_user.is_authenticated:
        return redirect(url_for('main.index'))
    
    form = RegisterForm()
    if form.validate_on_submit():
        # Check if user already exists
        if User.query.filter_by(email=form.email.data).first():
            flash('Email address already registered.', 'error')
            return render_template('auth/register.html', form=form)
        
        if User.query.filter_by(nickname=form.nickname.data).first():
            flash('Nickname already taken.', 'error')
            return render_template('auth/register.html', form=form)
        
        # Validate password strength
        if not is_valid_password(form.password.data):
            flash('Password must be at least 8 characters long and contain at least one letter and one number.', 'error')
            return render_template('auth/register.html', form=form)
        
        # Create new user
        user = User(
            nickname=form.nickname.data,
            email=form.email.data
        )
        user.set_password(form.password.data)
        
        try:
            db.session.add(user)
            db.session.commit()
            flash('Registration successful! You can now log in.', 'success')
            return redirect(url_for('auth.login'))
        except Exception as e:
            db.session.rollback()
            flash('An error occurred during registration. Please try again.', 'error')
    
    return render_template('auth/register.html', form=form)

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

@auth.route('/forgot-password', methods=['GET', 'POST'])
def forgot_password():
    """Forgot password page"""
    if current_user.is_authenticated:
        return redirect(url_for('main.index'))
    
    form = ForgotPasswordForm()
    if form.validate_on_submit():
        user = User.query.filter_by(email=form.email.data).first()
        if user:
            # TODO: Implement email sending for password reset
            flash('If an account with that email exists, we\'ve sent password reset instructions.', 'info')
        else:
            flash('If an account with that email exists, we\'ve sent password reset instructions.', 'info')
        return redirect(url_for('auth.login'))
    
    return render_template('auth/forgot_password.html', form=form)

def is_valid_password(password):
    """Validate password strength"""
    if len(password) < 8:
        return False
    if not re.search(r'[A-Za-z]', password):
        return False
    if not re.search(r'\d', password):
        return False
    return True