import json
import bcrypt
from flask_login import UserMixin
import os

class User(UserMixin):
    def __init__(self, username):
        self.id = username
        self.username = username

    @staticmethod
    def get(user_id):
        users = load_users()
        if user_id in users:
            return User(user_id)
        return None

def init_auth_file():
    """Initialize auth.json if it doesn't exist"""
    if not os.path.exists('auth.json'):
        with open('auth.json', 'w') as f:
            json.dump({}, f)

def load_users():
    """Load users from auth.json"""
    init_auth_file()
    with open('auth.json', 'r') as f:
        return json.load(f)

def save_users(users):
    """Save users to auth.json"""
    with open('auth.json', 'w') as f:
        json.dump(users, f, indent=2)

def hash_password(password):
    """Hash a password using bcrypt"""
    return bcrypt.hashpw(password.encode('utf-8'), bcrypt.gensalt()).decode('utf-8')

def verify_password(stored_password_hash, provided_password):
    """Verify a password against its hash"""
    return bcrypt.checkpw(
        provided_password.encode('utf-8'),
        stored_password_hash.encode('utf-8')
    )

def create_user(username, password):
    """Create a new user with hashed password"""
    users = load_users()
    if username not in users:
        users[username] = {
            'password_hash': hash_password(password)
        }
        save_users(users)
        return True
    return False

def verify_user(username, password):
    """Verify user credentials"""
    users = load_users()
    if username in users:
        stored_hash = users[username]['password_hash']
        return verify_password(stored_hash, password)
    return False

def change_password(username, current_password, new_password):
    """Change user password if current password is correct"""
    if verify_user(username, current_password):
        users = load_users()
        users[username]['password_hash'] = hash_password(new_password)
        save_users(users)
        return True
    return False

# Initialize default users with secure passwords
def init_default_users():
    """Initialize default users if they don't exist"""
    init_auth_file()
    users = load_users()
    
    default_users = ['chaulmark', 'ekragh']
    default_password = 'changeme123'  # Temporary password that users should change
    
    for username in default_users:
        if username not in users:
            create_user(username, default_password)