from flask import Blueprint, request, jsonify, current_app
from flask_jwt_extended import jwt_required, get_jwt_identity
from email_validator import validate_email, EmailNotValidError
from backend.services.auth_service import register_user, login_user, get_user_by_id, request_password_reset, reset_user_password
from backend.models.user import User
from backend.utils.country_language_data import COUNTRIES, LANGUAGES

auth_bp = Blueprint('auth', __name__)

def validate_email_format(email: str) -> tuple[bool, str]:
    """
    Validate email format using email-validator library.

    Args:
        email: Email string to validate

    Returns:
        Tuple of (is_valid, validated_email_or_error_message)
    """
    try:
        validated = validate_email(email)
        return True, validated['email']
    except EmailNotValidError as e:
        return False, str(e)

@auth_bp.route('/', methods=['OPTIONS'])
def handle_options():
    """Handle OPTIONS requests for preflight CORS checks."""
    return '', 200

@auth_bp.route('/register', methods=['OPTIONS'])
def handle_register_options():
    """Handle OPTIONS requests for preflight CORS checks for register route."""
    return '', 200

@auth_bp.route('/register', methods=['POST'])
def register():
    """
    Register a new user.

    Request Body:
        email (str): User email
        password (str): User password
        country (str, optional): User country (ISO 3166-1 alpha-2 code)
        language (str, optional): User language (ISO 639-1 code)

    Returns:
        JSON: Registration result
    """
    try:
        data = request.get_json()

        # Validate required fields
        if not data or not all(k in data for k in ('email', 'password')):
            return jsonify({
                'success': False,
                'message': 'Email and password are required'
            }), 400

        email = data['email']
        password = data['password']
        country = data.get('country')  # Optional: User country (ISO 3166-1 alpha-2 code)
        language = data.get('language')  # Optional: User language (ISO 639-1 code)

        # Validate email format using email-validator
        is_valid_email, validated_email_or_error = validate_email_format(email)
        if not is_valid_email:
            return jsonify({
                'success': False,
                'message': f'Invalid email format: {validated_email_or_error}'
            }), 400

        # Use validated email (it may be normalized)
        email = validated_email_or_error

        # Validate password strength
        password_validation = validate_password_strength(password)
        if not password_validation['valid']:
            return jsonify({
                'success': False,
                'message': password_validation['message']
            }), 400

        # Optional: Validate country and language parameters if provided
        if country:
            # Validate if country is a valid ISO 3166-1 alpha-2 code
            if not isinstance(country, str) or len(country) != 2 or not country.isalpha():
                return jsonify({
                    'success': False,
                    'message': 'Country must be a valid ISO 3166-1 alpha-2 code (2 alphabetic characters)'
                }), 400

        if language:
            # Validate if language is a valid ISO 639-1 code
            if not isinstance(language, str) or len(language) != 2 or not language.isalpha():
                return jsonify({
                    'success': False,
                    'message': 'Language must be a valid ISO 639-1 code (2 alphabetic characters)'
                }), 400

        # Register user with preferences
        result = register_user(email, password, country, language)

        if result['success']:
            return jsonify(result), 201
        else:
            # Avoid exposing specific reasons for registration failure (security)
            if 'already exist' in result.get('message', '').lower():
                return jsonify({
                    'success': False,
                    'message': 'Account with this email already exists'
                }), 400
            return jsonify(result), 400

    except Exception as e:
        current_app.logger.error(f"Registration error: {str(e)}")
        return jsonify({
            'success': False,
            'message': 'An error occurred during registration'
        }), 500

@auth_bp.route('/login', methods=['OPTIONS'])
def handle_login_options():
    """Handle OPTIONS requests for preflight CORS checks for login route."""
    from flask import current_app
    current_app.logger.info(f"OPTIONS request for /login from {request.remote_addr}")
    current_app.logger.info(f"Request headers: {dict(request.headers)}")
    return '', 200

@auth_bp.route('/login', methods=['POST'])
def login():
    """
    Authenticate and login a user.

    Request Body:
        email (str): User email
        password (str): User password
        remember_me (bool): Remember me flag for extended session (optional)

    Returns:
        JSON: Login result with JWT token
    """
    try:
        # Log the incoming request
        current_app.logger.info(f"Login request received from {request.remote_addr}")
        current_app.logger.info(f"Request headers: {dict(request.headers)}")

        data = request.get_json()

        # Validate required fields
        if not data or not all(k in data for k in ('email', 'password')):
            current_app.logger.warning("Login failed: Missing email or password")
            return jsonify({
                'success': False,
                'message': 'Email and password are required'
            }), 400

        email = data['email']
        password = data['password']
        remember_me = data.get('remember_me', False)

        # Validate email format
        is_valid_email, validated_email_or_error = validate_email_format(email)
        if not is_valid_email:
            current_app.logger.warning(f"Login attempt with invalid email format: {email}")
            # Do not reveal that email format is invalid to avoid enumeration
            return jsonify({
                'success': False,
                'message': 'Invalid email or password'
            }), 401

        # Use validated email (it may be normalized)
        email = validated_email_or_error

        # Login user
        result = login_user(email, password, remember_me)

        if result['success']:
            # Set CORS headers explicitly
            response_data = jsonify(result)
            response_data.headers.add('Access-Control-Allow-Origin', 'http://localhost:3000')
            response_data.headers.add('Access-Control-Allow-Credentials', 'true')
            current_app.logger.info(f"Login successful for user {email}")
            return response_data, 200
        else:
            current_app.logger.warning(f"Login failed for user {email}: {result.get('message', 'Unknown error')}")
            return jsonify(result), 401

    except Exception as e:
        current_app.logger.error(f"Login error: {str(e)}", exc_info=True)
        return jsonify({
            'success': False,
            'message': 'An error occurred during login'
        }), 500

@auth_bp.route('/logout', methods=['OPTIONS'])
def handle_logout_options():
    """Handle OPTIONS requests for preflight CORS checks for logout route."""
    return '', 200

@auth_bp.route('/logout', methods=['POST'])
@jwt_required()
def logout():
    """
    Logout current user.

    Returns:
        JSON: Logout result
    """
    try:
        current_app.logger.info(f"Logout request for user: {get_jwt_identity()}")
        return jsonify({
            'success': True,
            'message': 'Logged out successfully'
        }), 200

    except Exception as e:
        current_app.logger.error(f"Logout error: {str(e)}")
        return jsonify({
            'success': False,
            'message': 'An error occurred during logout'
        }), 500

@auth_bp.route('/user', methods=['OPTIONS'])
def handle_user_options():
    """Handle OPTIONS requests for preflight CORS checks for user route."""
    return '', 200

@auth_bp.route('/user', methods=['GET'])
@jwt_required()
def get_current_user():
    """
    Get current authenticated user.

    Returns:
        JSON: Current user data
    """
    try:
        user_id = get_jwt_identity()
        current_app.logger.info(f"Get user profile request for user: {user_id}")
        user_data = get_user_by_id(user_id)

        if user_data:
            # Remove sensitive information from user data
            safe_user_data = {k: v for k, v in user_data.items() if k not in ['password', 'password_hash']}
            return jsonify({
                'success': True,
                'user': safe_user_data
            }), 200
        else:
            return jsonify({
                'success': False,
                'message': 'User not found'
            }), 404

    except Exception as e:
        current_app.logger.error(f"Get user error: {str(e)}")
        return jsonify({
            'success': False,
            'message': 'An error occurred while fetching user data'
        }), 500

@auth_bp.route('/registration-options', methods=['GET'])
def get_registration_options():
    """
    Get registration options including countries and languages.

    Returns:
        JSON: Registration options
    """
    try:
        return jsonify({
            'success': True,
            'countries': COUNTRIES,
            'languages': LANGUAGES
        }), 200

    except Exception as e:
        current_app.logger.error(f"Get registration options error: {str(e)}")
        return jsonify({
            'success': False,
            'message': 'An error occurred while fetching registration options'
        }), 500

@auth_bp.route('/forgot-password', methods=['OPTIONS'])
def handle_forgot_password_options():
    """Handle OPTIONS requests for preflight CORS checks for forgot password route."""
    return '', 200


@auth_bp.route('/forgot-password', methods=['POST'])
def forgot_password():
    """
    Request password reset for a user.

    Request Body:
        email (str): User email

    Returns:
        JSON: Password reset request result
    """
    try:
        data = request.get_json()

        # Validate required fields
        if not data or 'email' not in data:
            return jsonify({
                'success': False,
                'message': 'Email is required'
            }), 400

        email = data['email']

        # Validate email format
        is_valid_email, validated_email_or_error = validate_email_format(email)
        if not is_valid_email:
            # Don't reveal that email format is invalid to prevent enumeration
            current_app.logger.warning(f"Forgot password request with invalid email format: {email}")
            # Return success to prevent user enumeration
            return jsonify({
                'success': True,
                'message': 'If an account exists with this email, password reset instructions have been sent.'
            }), 200

        # Use validated email (it may be normalized)
        email = validated_email_or_error

        # Request password reset (this should be handled in a way that doesn't reveal user existence)
        result = request_password_reset(current_app.supabase, email)

        # Always return success to prevent user enumeration
        return jsonify({
            'success': True,
            'message': 'If an account exists with this email, password reset instructions have been sent.'
        }), 200

    except Exception as e:
        current_app.logger.error(f"Forgot password error: {str(e)}")
        # Even on error, don't reveal if user exists
        return jsonify({
            'success': True,
            'message': 'If an account exists with this email, password reset instructions have been sent.'
        }), 200


@auth_bp.route('/reset-password', methods=['OPTIONS'])
def handle_reset_password_options():
    """Handle OPTIONS requests for preflight CORS checks for reset password route."""
    return '', 200

@auth_bp.route('/reset-password', methods=['GET'])
def show_reset_password_form():
    """
    Serve the password reset form.
    This endpoint is accessed via the link sent in the password reset email.
    The token will be available as a query parameter (e.g., ?token=abc123).
    The SPA frontend should read this token and display the form accordingly.
    """
    # Log the access for monitoring
    current_app.logger.info("Password reset form page accessed.")
    # For an SPA, serving index.html allows the frontend router to take over.
    # The frontend can access query parameters like 'token' using its router or window.location.
    # No specific action is needed here other than ensuring the route is recognized.
    # The main app.py serve_frontend will ultimately serve the SPA's index.html.
    return '', 200 # Let the main SPA handler take over

@auth_bp.route('/reset-password', methods=['POST'])
def reset_password():
    """
    Reset user password with token.

    Request Body:
        token (str): Password reset token
        password (str): New password

    Returns:
        JSON: Password reset result
    """
    try:
        data = request.get_json()

        # Validate required fields
        if not data or not all(k in data for k in ('token', 'password')):
            return jsonify({
                'success': False,
                'message': 'Token and password are required'
            }), 400

        token = data['token']
        password = data['password']

        # Validate password strength
        password_validation = validate_password_strength(password)
        if not password_validation['valid']:
            return jsonify({
                'success': False,
                'message': password_validation['message']
            }), 400

        # Reset password
        result = reset_user_password(current_app.supabase, token, password)

        if result['success']:
            return jsonify(result), 200
        else:
            return jsonify(result), 400

    except Exception as e:
        current_app.logger.error(f"Reset password error: {str(e)}")
        return jsonify({
            'success': False,
            'message': 'An error occurred while resetting your password'
        }), 500

def validate_password_strength(password: str) -> dict:
    """
    Validates password strength based on security requirements.

    Args:
        password: Password string to validate

    Returns:
        Dictionary with validation result and message
    """
    if len(password) < 8:
        return {
            'valid': False,
            'message': 'Password must be at least 8 characters long'
        }

    # Check for complexity requirements
    has_upper = any(c.isupper() for c in password)
    has_lower = any(c.islower() for c in password)
    has_digit = any(c.isdigit() for c in password)
    has_special = any(c in "!@#$%^&*()_+-=[]{}|;:,.<>?" for c in password)

    if not has_upper:
        return {
            'valid': False,
            'message': 'Password must contain at least one uppercase letter'
        }

    if not has_lower:
        return {
            'valid': False,
            'message': 'Password must contain at least one lowercase letter'
        }

    if not has_digit:
        return {
            'valid': False,
            'message': 'Password must contain at least one number'
        }

    if not has_special:
        return {
            'valid': False,
            'message': 'Password must contain at least one special character'
        }

    return {
        'valid': True,
        'message': 'Password is valid'
    }