using System.Diagnostics;
using System.Net.NetworkInformation;
using System.Runtime.InteropServices;
using Microsoft.Extensions.Logging;

namespace QemuVmManager.Core;

public interface INetworkManager
{
    Task<bool> IsBridgeAvailableAsync(string bridgeName);
    Task<bool> CreateBridgeAsync(string bridgeName, string? interfaceName = null);
    Task<bool> DeleteBridgeAsync(string bridgeName);
    Task<List<string>> GetAvailableBridgesAsync();
    Task<List<string>> GetNetworkInterfacesAsync();
    Task<bool> AddInterfaceToBridgeAsync(string bridgeName, string interfaceName);
    Task<bool> RemoveInterfaceFromBridgeAsync(string bridgeName, string interfaceName);
    Task<string?> GetBridgeIpAddressAsync(string bridgeName);
    Task<bool> ConfigureBridgeAsync(string bridgeName, string ipAddress, string netmask);
}

public class NetworkManager : INetworkManager
{
    private readonly ILogger<NetworkManager>? _logger;

    public NetworkManager(ILogger<NetworkManager>? logger = null)
    {
        _logger = logger;
    }

    public async Task<bool> IsBridgeAvailableAsync(string bridgeName)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await CheckLinuxBridgeAsync(bridgeName);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await CheckWindowsBridgeAsync(bridgeName);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await CheckMacOSBridgeAsync(bridgeName);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "Failed to check bridge availability for {BridgeName}", bridgeName);
            return false;
        }
    }

    public async Task<bool> CreateBridgeAsync(string bridgeName, string? interfaceName = null)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await CreateLinuxBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await CreateWindowsBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await CreateMacOSBridgeAsync(bridgeName, interfaceName);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to create bridge {BridgeName}", bridgeName);
            return false;
        }
    }

    public async Task<bool> DeleteBridgeAsync(string bridgeName)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await DeleteLinuxBridgeAsync(bridgeName);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await DeleteWindowsBridgeAsync(bridgeName);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await DeleteMacOSBridgeAsync(bridgeName);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to delete bridge {BridgeName}", bridgeName);
            return false;
        }
    }

    public async Task<List<string>> GetAvailableBridgesAsync()
    {
        var bridges = new List<string>();
        
        try
        {
            if (OperatingSystem.IsLinux())
            {
                bridges.AddRange(await GetLinuxBridgesAsync());
            }
            else if (OperatingSystem.IsWindows())
            {
                bridges.AddRange(await GetWindowsBridgesAsync());
            }
            else if (OperatingSystem.IsMacOS())
            {
                bridges.AddRange(await GetMacOSBridgesAsync());
            }
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "Failed to get available bridges");
        }
        
        return bridges;
    }

    public async Task<List<string>> GetNetworkInterfacesAsync()
    {
        var interfaces = new List<string>();
        
        try
        {
            var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
            
            foreach (var ni in networkInterfaces)
            {
                // Filter out loopback and virtual interfaces
                if (ni.NetworkInterfaceType != NetworkInterfaceType.Loopback &&
                    ni.OperationalStatus == OperationalStatus.Up &&
                    !ni.Name.Contains("vEthernet") &&
                    !ni.Name.Contains("VirtualBox") &&
                    !ni.Name.Contains("VMware"))
                {
                    interfaces.Add(ni.Name);
                }
            }
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "Failed to get network interfaces");
        }
        
        return interfaces;
    }

    public async Task<bool> AddInterfaceToBridgeAsync(string bridgeName, string interfaceName)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await AddInterfaceToLinuxBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await AddInterfaceToWindowsBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await AddInterfaceToMacOSBridgeAsync(bridgeName, interfaceName);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to add interface {InterfaceName} to bridge {BridgeName}", interfaceName, bridgeName);
            return false;
        }
    }

    public async Task<bool> RemoveInterfaceFromBridgeAsync(string bridgeName, string interfaceName)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await RemoveInterfaceFromLinuxBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await RemoveInterfaceFromWindowsBridgeAsync(bridgeName, interfaceName);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await RemoveInterfaceFromMacOSBridgeAsync(bridgeName, interfaceName);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to remove interface {InterfaceName} from bridge {BridgeName}", interfaceName, bridgeName);
            return false;
        }
    }

    public async Task<string?> GetBridgeIpAddressAsync(string bridgeName)
    {
        try
        {
            var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
            
            foreach (var ni in networkInterfaces)
            {
                if (ni.Name.Equals(bridgeName, StringComparison.OrdinalIgnoreCase))
                {
                    var ipProps = ni.GetIPProperties();
                    var unicastAddresses = ipProps.UnicastAddresses;
                    
                    foreach (var addr in unicastAddresses)
                    {
                        if (addr.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                        {
                            return addr.Address.ToString();
                        }
                    }
                }
            }
            
            return null;
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "Failed to get IP address for bridge {BridgeName}", bridgeName);
            return null;
        }
    }

    public async Task<bool> ConfigureBridgeAsync(string bridgeName, string ipAddress, string netmask)
    {
        try
        {
            if (OperatingSystem.IsLinux())
            {
                return await ConfigureLinuxBridgeAsync(bridgeName, ipAddress, netmask);
            }
            else if (OperatingSystem.IsWindows())
            {
                return await ConfigureWindowsBridgeAsync(bridgeName, ipAddress, netmask);
            }
            else if (OperatingSystem.IsMacOS())
            {
                return await ConfigureMacOSBridgeAsync(bridgeName, ipAddress, netmask);
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to configure bridge {BridgeName}", bridgeName);
            return false;
        }
    }

    // Linux-specific implementations
    private async Task<bool> CheckLinuxBridgeAsync(string bridgeName)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "brctl",
                Arguments = $"show {bridgeName}",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return false;

        await process.WaitForExitAsync();
        return process.ExitCode == 0;
    }

    private async Task<bool> CreateLinuxBridgeAsync(string bridgeName, string? interfaceName)
    {
        // Create bridge
        var createProcess = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "sudo",
                Arguments = $"brctl addbr {bridgeName}",
                UseShellExecute = false,
                CreateNoWindow = true
            }
        };

        var started = createProcess.Start();
        if (!started) return false;

        await createProcess.WaitForExitAsync();
        if (createProcess.ExitCode != 0) return false;

        // Add interface if specified
        if (!string.IsNullOrEmpty(interfaceName))
        {
            return await AddInterfaceToLinuxBridgeAsync(bridgeName, interfaceName);
        }

        return true;
    }

    private async Task<bool> DeleteLinuxBridgeAsync(string bridgeName)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "sudo",
                Arguments = $"brctl delbr {bridgeName}",
                UseShellExecute = false,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return false;

        await process.WaitForExitAsync();
        return process.ExitCode == 0;
    }

    private async Task<List<string>> GetLinuxBridgesAsync()
    {
        var bridges = new List<string>();
        
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "brctl",
                Arguments = "show",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return bridges;

        var output = await process.StandardOutput.ReadToEndAsync();
        await process.WaitForExitAsync();

        if (process.ExitCode == 0)
        {
            var lines = output.Split('\n', StringSplitOptions.RemoveEmptyEntries);
            foreach (var line in lines.Skip(1)) // Skip header
            {
                var parts = line.Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length > 0)
                {
                    bridges.Add(parts[0]);
                }
            }
        }

        return bridges;
    }

    private async Task<bool> AddInterfaceToLinuxBridgeAsync(string bridgeName, string interfaceName)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "sudo",
                Arguments = $"brctl addif {bridgeName} {interfaceName}",
                UseShellExecute = false,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return false;

        await process.WaitForExitAsync();
        return process.ExitCode == 0;
    }

    private async Task<bool> RemoveInterfaceFromLinuxBridgeAsync(string bridgeName, string interfaceName)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "sudo",
                Arguments = $"brctl delif {bridgeName} {interfaceName}",
                UseShellExecute = false,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return false;

        await process.WaitForExitAsync();
        return process.ExitCode == 0;
    }

    private async Task<bool> ConfigureLinuxBridgeAsync(string bridgeName, string ipAddress, string netmask)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = "sudo",
                Arguments = $"ip addr add {ipAddress}/{netmask} dev {bridgeName}",
                UseShellExecute = false,
                CreateNoWindow = true
            }
        };

        var started = process.Start();
        if (!started) return false;

        await process.WaitForExitAsync();
        return process.ExitCode == 0;
    }

    // Windows-specific implementations (simplified - would need more complex implementation)
    private async Task<bool> CheckWindowsBridgeAsync(string bridgeName)
    {
        // Windows bridge checking would require PowerShell or WMI
        // For now, return false as Windows bridge setup is more complex
        return false;
    }

    private async Task<bool> CreateWindowsBridgeAsync(string bridgeName, string? interfaceName)
    {
        // Windows bridge creation requires PowerShell or Hyper-V
        // For now, return false as this requires more complex implementation
        return false;
    }

    private async Task<bool> DeleteWindowsBridgeAsync(string bridgeName)
    {
        // Windows bridge deletion requires PowerShell or Hyper-V
        return false;
    }

    private async Task<List<string>> GetWindowsBridgesAsync()
    {
        // Windows bridge enumeration would require PowerShell or WMI
        return new List<string>();
    }

    private async Task<bool> AddInterfaceToWindowsBridgeAsync(string bridgeName, string interfaceName)
    {
        return false;
    }

    private async Task<bool> RemoveInterfaceFromWindowsBridgeAsync(string bridgeName, string interfaceName)
    {
        return false;
    }

    private async Task<bool> ConfigureWindowsBridgeAsync(string bridgeName, string ipAddress, string netmask)
    {
        return false;
    }

    // macOS-specific implementations
    private async Task<bool> CheckMacOSBridgeAsync(string bridgeName)
    {
        try
        {
            var process = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = "ifconfig",
                    Arguments = bridgeName,
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    CreateNoWindow = true
                }
            };

            var started = process.Start();
            if (!started) return false;

            await process.WaitForExitAsync();
            return process.ExitCode == 0;
        }
        catch
        {
            return false;
        }
    }

    private async Task<bool> CreateMacOSBridgeAsync(string bridgeName, string? interfaceName)
    {
        try
        {
            // On macOS, bridge creation is complex and typically requires system configuration
            // For now, we'll check if the bridge already exists and return true if it does
            var exists = await CheckMacOSBridgeAsync(bridgeName);
            if (exists)
            {
                _logger?.LogInformation("Bridge {BridgeName} already exists on macOS", bridgeName);
                return true;
            }

            _logger?.LogWarning("Bridge creation on macOS requires manual system configuration");
            _logger?.LogInformation("You can use existing bridge0 or create bridges manually");
            return false;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to create bridge {BridgeName} on macOS", bridgeName);
            return false;
        }
    }

    private async Task<bool> DeleteMacOSBridgeAsync(string bridgeName)
    {
        // Bridge deletion on macOS requires system configuration
        _logger?.LogWarning("Bridge deletion on macOS requires manual system configuration");
        return false;
    }

    private async Task<List<string>> GetMacOSBridgesAsync()
    {
        var bridges = new List<string>();
        
        try
        {
            var process = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = "ifconfig",
                    Arguments = "-a",
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    CreateNoWindow = true
                }
            };

            var started = process.Start();
            if (!started) return bridges;

            var output = await process.StandardOutput.ReadToEndAsync();
            await process.WaitForExitAsync();

            if (process.ExitCode == 0)
            {
                var lines = output.Split('\n', StringSplitOptions.RemoveEmptyEntries);
                foreach (var line in lines)
                {
                    if (line.Contains("bridge") && line.Contains(":"))
                    {
                        var parts = line.Split(':');
                        if (parts.Length > 0)
                        {
                            var bridgeName = parts[0].Trim();
                            if (!string.IsNullOrEmpty(bridgeName) && !bridges.Contains(bridgeName))
                            {
                                bridges.Add(bridgeName);
                            }
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "Failed to get macOS bridges");
        }
        
        return bridges;
    }

    private async Task<bool> AddInterfaceToMacOSBridgeAsync(string bridgeName, string interfaceName)
    {
        // Interface management on macOS bridges requires system configuration
        _logger?.LogWarning("Interface management on macOS bridges requires manual system configuration");
        return false;
    }

    private async Task<bool> RemoveInterfaceFromMacOSBridgeAsync(string bridgeName, string interfaceName)
    {
        // Interface management on macOS bridges requires system configuration
        _logger?.LogWarning("Interface management on macOS bridges requires manual system configuration");
        return false;
    }

    private async Task<bool> ConfigureMacOSBridgeAsync(string bridgeName, string ipAddress, string netmask)
    {
        try
        {
            var process = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = "sudo",
                    Arguments = $"ifconfig {bridgeName} {ipAddress} netmask 255.255.255.0",
                    UseShellExecute = false,
                    CreateNoWindow = true
                }
            };

            var started = process.Start();
            if (!started) return false;

            await process.WaitForExitAsync();
            return process.ExitCode == 0;
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Failed to configure bridge {BridgeName} on macOS", bridgeName);
            return false;
        }
    }
}