"""
IKEv2 Server Implementation for Outline VPN
"""

import os
import subprocess
import tempfile
from typing import Dict, Optional
import uuid
from datetime import datetime, timedelta

class IKEv2Server:
    def __init__(self, server_ip: str, logger):
        self.server_ip = server_ip
        self.logger = logger
        self.ca_dir = "ca"
        self.cert_dir = "certs"
        self.config_dir = "config"
        self._setup_directories()
        self._initialize_ca()

    def _setup_directories(self):
        """Create necessary directories"""
        for directory in [self.ca_dir, self.cert_dir, self.config_dir]:
            os.makedirs(directory, exist_ok=True)

    def _initialize_ca(self):
        """Initialize Certificate Authority if not already done"""
        ca_key = os.path.join(self.ca_dir, "ca.key")
        ca_cert = os.path.join(self.ca_dir, "ca.crt")

        if not os.path.exists(ca_key) or not os.path.exists(ca_cert):
            # Generate CA private key
            subprocess.run([
                "openssl", "genrsa",
                "-out", ca_key,
                "4096"
            ], check=True)

            # Generate CA certificate
            subprocess.run([
                "openssl", "req",
                "-x509",
                "-new",
                "-nodes",
                "-key", ca_key,
                "-sha256",
                "-days", "3650",
                "-out", ca_cert,
                "-subj", f"/CN=Outline VPN CA"
            ], check=True)

    def generate_certificate(self, user_id: str) -> Dict[str, str]:
        """Generate client certificate for IKEv2"""
        cert_name = f"client_{user_id}"
        key_path = os.path.join(self.cert_dir, f"{cert_name}.key")
        csr_path = os.path.join(self.cert_dir, f"{cert_name}.csr")
        cert_path = os.path.join(self.cert_dir, f"{cert_name}.crt")
        p12_path = os.path.join(self.cert_dir, f"{cert_name}.p12")

        try:
            # Generate client private key
            subprocess.run([
                "openssl", "genrsa",
                "-out", key_path,
                "2048"
            ], check=True)

            # Generate CSR
            subprocess.run([
                "openssl", "req",
                "-new",
                "-key", key_path,
                "-out", csr_path,
                "-subj", f"/CN=client_{user_id}"
            ], check=True)

            # Sign client certificate with CA
            subprocess.run([
                "openssl", "x509",
                "-req",
                "-in", csr_path,
                "-CA", os.path.join(self.ca_dir, "ca.crt"),
                "-CAkey", os.path.join(self.ca_dir, "ca.key"),
                "-CAcreateserial",
                "-out", cert_path,
                "-days", "365",
                "-sha256"
            ], check=True)

            # Create PKCS12 bundle
            export_password = str(uuid.uuid4())
            subprocess.run([
                "openssl", "pkcs12",
                "-export",
                "-in", cert_path,
                "-inkey", key_path,
                "-out", p12_path,
                "-password", f"pass:{export_password}"
            ], check=True)

            # Read certificate files
            with open(cert_path, 'r') as f:
                cert_data = f.read()
            with open(key_path, 'r') as f:
                key_data = f.read()
            with open(os.path.join(self.ca_dir, "ca.crt"), 'r') as f:
                ca_data = f.read()
            
            return {
                'certificate': cert_data,
                'private_key': key_data,
                'ca_certificate': ca_data,
                'p12_bundle': p12_path,
                'p12_password': export_password
            }

        except Exception as e:
            self.logger.error("Error generating certificate: " + str(e))
            raise

    def generate_strongswan_config(self, user_id: str, psk: str) -> str:
        """Generate strongSwan configuration for a user"""
        config = f"""
conn outline-{user_id}
    auto=add
    compress=no
    type=tunnel
    keyexchange=ikev2
    fragmentation=yes
    forceencaps=yes
    
    # Local/Server configuration
    left=%any
    leftsubnet=0.0.0.0/0
    leftcert=/etc/ipsec.d/certs/server.crt
    leftsendcert=always
    leftid=@outline.vpn
    
    # Remote/Client configuration
    right=%any
    rightid=%any
    rightauth=eap-mschapv2
    rightsourceip=10.10.10.0/24
    rightdns=8.8.8.8,8.8.4.4
    
    # Security parameters
    ike=aes256-sha256-modp2048,aes128-sha1-modp2048
    esp=aes256-sha256,aes128-sha1
    dpdaction=clear
    dpddelay=300s
    rekey=no
"""
        config_path = os.path.join(self.config_dir, f"outline-{user_id}.conf")
        with open(config_path, 'w') as f:
            f.write(config)
        
        return config_path

    def add_user(self, user_id: str, username: str, password: str, psk: str):
        """Add a new VPN user"""
        # Generate certificates
        cert_data = self.generate_certificate(user_id)
        
        # Generate strongSwan config
        config_path = self.generate_strongswan_config(user_id, psk)
        
        # Add user credentials to strongSwan secrets
        secrets_path = os.path.join(self.config_dir, "ipsec.secrets")
        with open(secrets_path, 'a') as f:
            f.write(f'{username} : EAP "{password}"\n')
            f.write(f'{self.server_ip} %any : PSK "{psk}"\n')

        return cert_data

    def remove_user(self, user_id: str):
        """Remove a VPN user"""
        # Remove certificates
        cert_name = f"client_{user_id}"
        for ext in ['.key', '.csr', '.crt', '.p12']:
            path = os.path.join(self.cert_dir, f"{cert_name}{ext}")
            if os.path.exists(path):
                os.remove(path)

        # Remove config
        config_path = os.path.join(self.config_dir, f"outline-{user_id}.conf")
        if os.path.exists(config_path):
            os.remove(config_path)

        # Remove from secrets (would need to rewrite the file)
        # This is a bit more complex and would require parsing and rewriting ipsec.secrets


    async def start(self):
        """Start the IKEv2 service"""
        self.logger.info("Starting IKEv2 service...")
        # Placeholder for actual IKEv2 service startup logic
        # This might involve starting strongSwan or similar
        pass

    async def stop(self):
        """Stop the IKEv2 service"""
        self.logger.info("Stopping IKEv2 service...")
        # Placeholder for actual IKEv2 service shutdown logic
        pass