"""User model for authentication"""
import os
import yaml
from flask_login import UserMixin
import bcrypt


class User(UserMixin):
    """User model for product owners and administrators

    Attributes:
        user_id: Unique user identifier
        username: Username for login
        email: User email address
        password_hash: Bcrypt hashed password
        role: User role ('product_owner' or 'administrator')
        product_ids: List of product IDs (for product_owner role)
        is_active: Whether user account is active
    """

    def __init__(self, user_id, username, email, password_hash, role, product_ids=None, is_active=True):
        self.user_id = user_id
        self.username = username
        self.email = email
        self.password_hash = password_hash
        self.role = role
        self.product_ids = product_ids or []
        self.is_active = is_active

    def get_id(self):
        """Get user ID for Flask-Login"""
        return self.user_id

    @property
    def is_authenticated(self):
        """Check if user is authenticated"""
        return True

    @property
    def is_anonymous(self):
        """Check if user is anonymous"""
        return False

    def check_password(self, password):
        """Verify password against stored hash

        Args:
            password: Plain text password to verify

        Returns:
            bool: True if password matches, False otherwise
        """
        return bcrypt.checkpw(password.encode('utf-8'), self.password_hash.encode('utf-8'))

    @staticmethod
    def hash_password(password):
        """Hash password using bcrypt

        Args:
            password: Plain text password

        Returns:
            str: Hashed password
        """
        salt = bcrypt.gensalt()
        return bcrypt.hashpw(password.encode('utf-8'), salt).decode('utf-8')

    def to_dict(self):
        """Convert user to dictionary for storage

        Returns:
            dict: User data
        """
        return {
            'user_id': self.user_id,
            'username': self.username,
            'email': self.email,
            'password_hash': self.password_hash,
            'role': self.role,
            'product_ids': self.product_ids,
            'is_active': self.is_active
        }

    @classmethod
    def from_dict(cls, data):
        """Create user from dictionary

        Args:
            data: Dictionary with user data

        Returns:
            User: User instance
        """
        return cls(
            user_id=data['user_id'],
            username=data['username'],
            email=data['email'],
            password_hash=data['password_hash'],
            role=data['role'],
            product_ids=data.get('product_ids', []),
            is_active=data.get('is_active', True)
        )

    @staticmethod
    def _get_users_file():
        """Get path to users YAML file

        Returns:
            str: Path to users.yaml
        """
        from flask import current_app
        return os.path.join(current_app.config['DATA_DIR'], 'users.yaml')

    @staticmethod
    def _load_all_users():
        """Load all users from storage

        Returns:
            dict: Dictionary of user_id -> user_data
        """
        users_file = User._get_users_file()

        if not os.path.exists(users_file):
            return {}

        with open(users_file, 'r') as f:
            data = yaml.safe_load(f) or {}
            return data.get('users', {})

    @staticmethod
    def _save_all_users(users_dict):
        """Save all users to storage

        Args:
            users_dict: Dictionary of user_id -> user_data
        """
        users_file = User._get_users_file()
        os.makedirs(os.path.dirname(users_file), exist_ok=True)

        with open(users_file, 'w') as f:
            yaml.dump({'users': users_dict}, f, default_flow_style=False)

    @classmethod
    def get_by_id(cls, user_id):
        """Load user by ID

        Args:
            user_id: User ID to load

        Returns:
            User or None: User instance if found, None otherwise
        """
        users = cls._load_all_users()
        user_data = users.get(user_id)

        if user_data:
            return cls.from_dict(user_data)
        return None

    @classmethod
    def get_by_username(cls, username):
        """Load user by username

        Args:
            username: Username to search for

        Returns:
            User or None: User instance if found, None otherwise
        """
        users = cls._load_all_users()

        for user_data in users.values():
            if user_data['username'] == username:
                return cls.from_dict(user_data)
        return None

    @classmethod
    def get_all(cls):
        """Get all users

        Returns:
            list: List of User instances
        """
        users = cls._load_all_users()
        return [cls.from_dict(data) for data in users.values()]

    def save(self):
        """Save user to storage"""
        users = self._load_all_users()
        users[self.user_id] = self.to_dict()
        self._save_all_users(users)

    def delete(self):
        """Delete user from storage"""
        users = self._load_all_users()
        if self.user_id in users:
            del users[self.user_id]
            self._save_all_users(users)

    @classmethod
    def create(cls, username, email, password, role, product_ids=None):
        """Create new user

        Args:
            username: Username for login
            email: User email
            password: Plain text password
            role: User role ('product_owner' or 'administrator')
            product_ids: List of product IDs (for product_owner)

        Returns:
            User: Created user instance

        Raises:
            ValueError: If username already exists or role is invalid
        """
        # Validate role
        if role not in ['product_owner', 'administrator']:
            raise ValueError(f"Invalid role: {role}")

        # Check if username exists
        if cls.get_by_username(username):
            raise ValueError(f"Username already exists: {username}")

        # Generate user ID
        users = cls._load_all_users()
        if users:
            max_id = max([int(uid.replace('usr_', '')) for uid in users.keys()])
            user_id = f"usr_{max_id + 1:04d}"
        else:
            user_id = "usr_0001"

        # Hash password
        password_hash = cls.hash_password(password)

        # Create user
        user = cls(
            user_id=user_id,
            username=username,
            email=email,
            password_hash=password_hash,
            role=role,
            product_ids=product_ids or [],
            is_active=True
        )

        user.save()
        return user