"""OpenVPN process management."""

import os
import sys
import shutil
import subprocess
import tempfile
from pathlib import Path
from typing import Optional
from dataclasses import dataclass

from config import OPENVPN_SEARCH_PATHS, OPENVPN_CONFIG_DIR


@dataclass
class VPNStatus:
    """VPN connection status."""
    connected: bool
    vpn_ip: Optional[str] = None
    error: Optional[str] = None


class VPNManager:
    """Manages OpenVPN connections."""

    def __init__(self):
        self.process: Optional[subprocess.Popen] = None
        self.config_file: Optional[Path] = None
        self.log_file: Optional[Path] = None
        self._openvpn_path: Optional[str] = None

    def find_openvpn_binary(self) -> Optional[str]:
        """Find the OpenVPN binary on the system.

        Searches platform-specific paths and returns the first found binary.
        Returns None if not found.
        """
        if self._openvpn_path:
            return self._openvpn_path

        # First, check configured search paths
        for path in OPENVPN_SEARCH_PATHS:
            if Path(path).exists() and Path(path).is_file():
                self._openvpn_path = path
                return path

        # Try to find via PATH environment (works on all platforms)
        openvpn_in_path = shutil.which("openvpn")
        if openvpn_in_path:
            self._openvpn_path = openvpn_in_path
            return openvpn_in_path

        # macOS: Check for Tunnelblick's bundled OpenVPN
        if sys.platform == 'darwin':
            tunnelblick_base = Path("/Applications/Tunnelblick.app/Contents/Resources/openvpn")
            if tunnelblick_base.exists():
                # Find latest openvpn version directory
                for version_dir in sorted(tunnelblick_base.glob("openvpn-*"), reverse=True):
                    openvpn_binary = version_dir / "openvpn"
                    if openvpn_binary.exists():
                        self._openvpn_path = str(openvpn_binary)
                        return str(openvpn_binary)

        return None

    def check_openvpn_installed(self) -> bool:
        """Check if OpenVPN is installed."""
        return self.find_openvpn_binary() is not None

    def connect(self, config_content: str) -> VPNStatus:
        """Connect using provided OpenVPN config."""
        if self.process and self.process.poll() is None:
            return VPNStatus(connected=False, error="Already connected")

        openvpn_binary = self.find_openvpn_binary()
        if not openvpn_binary:
            return VPNStatus(
                connected=False,
                error="OpenVPN is not installed. Please install OpenVPN first.\n\n"
                      "Installation:\n"
                      "  Linux (Debian/Ubuntu): sudo apt install openvpn\n"
                      "  Linux (Fedora/RHEL): sudo dnf install openvpn\n"
                      "  macOS: brew install openvpn\n"
                      "  Windows: Download from https://openvpn.net/community-downloads/"
            )

        # Write config to temp file
        self.config_file = OPENVPN_CONFIG_DIR / "mguard-temp.ovpn"
        self.config_file.write_text(config_content)

        # Log file
        self.log_file = OPENVPN_CONFIG_DIR / "mguard.log"

        try:
            if os.name == 'nt':
                # Windows: Direct call (requires admin privileges)
                self.process = subprocess.Popen(
                    [openvpn_binary, "--config", str(self.config_file), "--log", str(self.log_file)],
                    creationflags=subprocess.CREATE_NO_WINDOW
                )
            else:
                # Linux/macOS: Use sudo openvpn
                self.process = subprocess.Popen(
                    ["sudo", openvpn_binary, "--config", str(self.config_file), "--log", str(self.log_file)],
                    stdout=subprocess.DEVNULL,
                    stderr=subprocess.DEVNULL
                )

            # Wait a bit for connection
            import time
            time.sleep(3)

            if self.process.poll() is not None:
                # Process ended, check for errors
                if self.log_file.exists():
                    log_content = self.log_file.read_text()
                    return VPNStatus(connected=False, error=f"Connection failed: {log_content[-500:]}")
                return VPNStatus(connected=False, error="Connection failed")

            return VPNStatus(connected=True)

        except PermissionError:
            return VPNStatus(
                connected=False,
                error="Permission denied. Run as administrator/root."
            )
        except Exception as e:
            return VPNStatus(connected=False, error=str(e))

    def disconnect(self) -> VPNStatus:
        """Disconnect VPN."""
        if not self.process:
            return VPNStatus(connected=False)

        try:
            self.process.terminate()
            self.process.wait(timeout=5)
        except subprocess.TimeoutExpired:
            self.process.kill()

        self.process = None

        # Clean up temp config
        if self.config_file and self.config_file.exists():
            self.config_file.unlink()

        return VPNStatus(connected=False)

    def get_status(self) -> VPNStatus:
        """Get current VPN status."""
        if not self.process:
            return VPNStatus(connected=False)

        if self.process.poll() is not None:
            # Process has ended
            self.process = None
            return VPNStatus(connected=False)

        # Try to get VPN IP from log
        vpn_ip = None
        if self.log_file and self.log_file.exists():
            try:
                log_content = self.log_file.read_text()
                # Parse for IP assignment
                for line in log_content.split('\n'):
                    if 'ifconfig' in line.lower() and 'netmask' in line.lower():
                        parts = line.split()
                        for i, part in enumerate(parts):
                            if part == 'ifconfig' and i + 1 < len(parts):
                                vpn_ip = parts[i + 1]
                                break
            except Exception:
                pass

        return VPNStatus(connected=True, vpn_ip=vpn_ip)

    def is_connected(self) -> bool:
        """Check if VPN is connected."""
        return self.process is not None and self.process.poll() is None

    def get_openvpn_info(self) -> dict:
        """Get information about the OpenVPN installation."""
        binary = self.find_openvpn_binary()
        return {
            "installed": binary is not None,
            "path": binary,
            "platform": sys.platform,
            "search_paths": OPENVPN_SEARCH_PATHS
        }