"""
Device fingerprinting utilities
Generates unique fingerprints for devices and browsers
"""

import hashlib
import json
from typing import Dict, Optional, Any


class DeviceFingerprint:
    """
    Device fingerprinting for security
    
    Creates unique fingerprints from device/browser characteristics
    to detect anomalies and prevent replay attacks
    """
    
    @staticmethod
    def generate_browser_fingerprint(
        user_agent: Optional[str] = None,
        accept_language: Optional[str] = None,
        screen_resolution: Optional[str] = None,
        timezone: Optional[str] = None,
        fonts: Optional[list] = None,
        canvas_hash: Optional[str] = None,
        webgl_hash: Optional[str] = None,
        plugins: Optional[list] = None
    ) -> str:
        """
        Generate browser fingerprint from available characteristics
        
        Args:
            user_agent: Browser user agent string
            accept_language: Accept-Language header
            screen_resolution: Screen resolution (e.g., "1920x1080")
            timezone: Browser timezone
            fonts: List of detected fonts
            canvas_hash: Canvas fingerprinting hash
            webgl_hash: WebGL fingerprinting hash
            plugins: List of browser plugins
        
        Returns:
            str: SHA-256 hash of fingerprint components
        """
        components = {
            "user_agent": user_agent or "",
            "accept_language": accept_language or "",
            "screen_resolution": screen_resolution or "",
            "timezone": timezone or "",
            "fonts": sorted(fonts) if fonts else [],
            "canvas_hash": canvas_hash or "",
            "webgl_hash": webgl_hash or "",
            "plugins": sorted(plugins) if plugins else []
        }
        
        # Create deterministic JSON string
        fingerprint_json = json.dumps(components, sort_keys=True, separators=(',', ':'))
        
        # Hash the fingerprint
        return hashlib.sha256(fingerprint_json.encode()).hexdigest()
    
    @staticmethod
    def generate_device_fingerprint(
        platform: str,
        os_version: Optional[str] = None,
        device_model: Optional[str] = None,
        hardware_id: Optional[str] = None,
        app_version: Optional[str] = None,
        install_id: Optional[str] = None
    ) -> str:
        """
        Generate mobile device fingerprint
        
        Args:
            platform: Device platform (ios/android)
            os_version: OS version
            device_model: Device model
            hardware_id: Hardware identifier
            app_version: App version
            install_id: Unique installation ID
        
        Returns:
            str: SHA-256 hash of device components
        """
        components = {
            "platform": platform.lower(),
            "os_version": os_version or "",
            "device_model": device_model or "",
            "hardware_id": hardware_id or "",
            "app_version": app_version or "",
            "install_id": install_id or ""
        }
        
        fingerprint_json = json.dumps(components, sort_keys=True, separators=(',', ':'))
        return hashlib.sha256(fingerprint_json.encode()).hexdigest()
    
    @staticmethod
    def generate_simple_fingerprint(
        user_agent: Optional[str] = None,
        ip_address: Optional[str] = None,
        accept_headers: Optional[Dict[str, str]] = None
    ) -> str:
        """
        Generate simple fingerprint from request headers
        
        Used as fallback when detailed fingerprinting is not available
        """
        components = {
            "user_agent": user_agent or "",
            "ip_address": ip_address or "",
            "accept": accept_headers.get("accept", "") if accept_headers else "",
            "accept_language": accept_headers.get("accept-language", "") if accept_headers else "",
            "accept_encoding": accept_headers.get("accept-encoding", "") if accept_headers else ""
        }
        
        fingerprint_json = json.dumps(components, sort_keys=True, separators=(',', ':'))
        return hashlib.sha256(fingerprint_json.encode()).hexdigest()
    
    @staticmethod
    def compare_fingerprints(
        fingerprint1: str,
        fingerprint2: str,
        tolerance: float = 0.0
    ) -> bool:
        """
        Compare two fingerprints
        
        Args:
            fingerprint1: First fingerprint
            fingerprint2: Second fingerprint
            tolerance: Similarity threshold (0.0 = exact match)
        
        Returns:
            bool: True if fingerprints match within tolerance
        """
        if tolerance == 0.0:
            return fingerprint1 == fingerprint2
        
        # For fuzzy matching, we could implement similarity algorithms
        # For now, exact match only
        return fingerprint1 == fingerprint2
    
    @staticmethod
    def extract_fingerprint_components(fingerprint_hash: str) -> Dict[str, Any]:
        """
        Extract components from a fingerprint (if stored separately)
        
        Note: This is a placeholder - in production, components would be
        stored alongside the hash for analysis
        """
        return {
            "hash": fingerprint_hash,
            "algorithm": "sha256",
            "components_stored": False
        }