#!/usr/bin/env python3
"""
Script to extract Tailscale DERP server IPv4 addresses from tailscale.json
and generate a Clash rule list file for direct connection.
"""

import json
import ipaddress
from pathlib import Path

def load_tailscale_data(json_file):
    """Load tailscale.json data"""
    with open(json_file, 'r', encoding='utf-8') as f:
        return json.load(f)

def extract_ipv4_addresses(data):
    """Extract all IPv4 addresses from tailscale regions data"""
    ipv4_addresses = set()
    
    for region_id, region_data in data['Regions'].items():
        for node in region_data.get('Nodes', []):
            ipv4 = node.get('IPv4')
            if ipv4:
                try:
                    # Validate IPv4 address
                    ipaddress.IPv4Address(ipv4)
                    ipv4_addresses.add(ipv4)
                except ipaddress.AddressValueError:
                    print(f"Invalid IPv4 address: {ipv4}")
    
    return sorted(ipv4_addresses)

def generate_clash_rules(ipv4_addresses, output_file):
    """Generate Clash rule list file"""
    with open(output_file, 'w', encoding='utf-8') as f:
        f.write("# Tailscale DERP Servers - Direct Connection Rules\n")
        f.write("# Generated from tailscale.json\n")
        f.write("# All Tailscale DERP relay servers should use direct connection\n\n")
        
        for ip in ipv4_addresses:
            f.write(f"IP-CIDR,{ip}/32\n")

def main():
    json_file = Path("tailscale.json")
    output_file = Path("Rules/Tailscale.list")
    
    if not json_file.exists():
        print(f"Error: {json_file} not found")
        return
    
    # Create Rules directory if it doesn't exist
    output_file.parent.mkdir(exist_ok=True)
    
    try:
        # Load tailscale data
        data = load_tailscale_data(json_file)
        
        # Extract IPv4 addresses
        ipv4_addresses = extract_ipv4_addresses(data)
        
        print(f"Found {len(ipv4_addresses)} unique IPv4 addresses")
        
        # Generate Clash rules
        generate_clash_rules(ipv4_addresses, output_file)
        
        print(f"Generated {output_file} successfully!")
        print(f"Rules created for {len(ipv4_addresses)} Tailscale DERP server IPs")
        
    except Exception as e:
        print(f"Error: {e}")

if __name__ == "__main__":
    main()