using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ResourceMonitorService.Configuration;
using ResourceMonitorService.Models;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;

namespace ResourceMonitorService.Services
{
    public interface IGameDetectionService
    {
        Task<GameInfo?> GetCurrentlyRunningGameAsync();
        Task<List<GameInfo>> GetAllDetectedGamesAsync();
        Task<bool> IsGameRunningFullscreenAsync();
        Task<float> GetGameFpsAsync(string processName);
    }

    public class GameDetectionService : IGameDetectionService
    {
        private readonly ILogger<GameDetectionService> _logger;
        private readonly MonitoringSettings _settings;

        // Windows API imports for fullscreen detection
        [DllImport("user32.dll")]
        private static extern IntPtr GetForegroundWindow();

        [DllImport("user32.dll")]
        private static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

        [DllImport("user32.dll")]
        private static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

        [DllImport("user32.dll")]
        private static extern int GetWindowTextLength(IntPtr hWnd);

        [DllImport("user32.dll")]
        private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);

        [DllImport("user32.dll")]
        private static extern bool IsWindowVisible(IntPtr hWnd);

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }

        public GameDetectionService(ILogger<GameDetectionService> logger, IOptions<MonitoringSettings> settings)
        {
            _logger = logger;
            _settings = settings.Value;
        }

        public async Task<GameInfo?> GetCurrentlyRunningGameAsync()
        {
            try
            {
                return await Task.Run(() =>
                {
                    var processes = Process.GetProcesses();

                    foreach (var process in processes)
                    {
                        try
                        {
                            if (process.MainModule?.FileName == null)
                                continue;

                            var filePath = process.MainModule.FileName;
                            var gameInfo = DetectGameFromPath(filePath, process);

                            if (gameInfo != null)
                            {
                                gameInfo.IsFullscreen = IsGameRunningFullscreenAsync().Result;
                                gameInfo.FPS = GetGameFpsAsync(process.ProcessName).Result;
                                return gameInfo;
                            }
                        }
                        catch (Exception ex)
                        {
                            // Handle access exceptions silently - some processes can't be accessed
                            _logger.LogTrace(ex, "Could not access process {ProcessName}", process.ProcessName);
                        }
                    }

                    return null;
                });
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error detecting currently running game");
                return null;
            }
        }

        public async Task<List<GameInfo>> GetAllDetectedGamesAsync()
        {
            try
            {
                return await Task.Run(() =>
                {
                    var games = new List<GameInfo>();
                    var processes = Process.GetProcesses();

                    foreach (var process in processes)
                    {
                        try
                        {
                            if (process.MainModule?.FileName == null)
                                continue;

                            var filePath = process.MainModule.FileName;
                            var gameInfo = DetectGameFromPath(filePath, process);

                            if (gameInfo != null)
                            {
                                games.Add(gameInfo);
                            }
                        }
                        catch (Exception ex)
                        {
                            _logger.LogTrace(ex, "Could not access process {ProcessName}", process.ProcessName);
                        }
                    }

                    return games;
                });
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error getting all detected games");
                return new List<GameInfo>();
            }
        }

        public async Task<bool> IsGameRunningFullscreenAsync()
        {
            try
            {
                return await Task.Run(() =>
                {
                    var foregroundWindow = GetForegroundWindow();
                    if (foregroundWindow == IntPtr.Zero)
                        return false;

                    if (!IsWindowVisible(foregroundWindow))
                        return false;

                    if (!GetWindowRect(foregroundWindow, out RECT rect))
                        return false;

                    // Get screen dimensions
                    var primaryScreen = System.Windows.Forms.Screen.PrimaryScreen;
                    if (primaryScreen == null)
                        return false;
                    var screenWidth = primaryScreen.Bounds.Width;
                    var screenHeight = primaryScreen.Bounds.Height;

                    // Check if window covers the entire screen
                    var windowWidth = rect.Right - rect.Left;
                    var windowHeight = rect.Bottom - rect.Top;

                    return windowWidth >= screenWidth && windowHeight >= screenHeight;
                });
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not determine if game is running fullscreen");
                return false;
            }
        }

        public async Task<float> GetGameFpsAsync(string processName)
        {
            try
            {
                return await Task.Run(() =>
                {
                    // This is a simplified FPS detection - in reality, you'd need more sophisticated methods
                    // such as hooking into DirectX/OpenGL or using external tools like RTSS

                    // For now, we'll return 0 as a placeholder
                    // In a real implementation, you might:
                    // 1. Use Windows Performance Toolkit (WPT) ETW events
                    // 2. Hook into D3D11/D3D12 present calls
                    // 3. Use NVIDIA's NVAPI or AMD's ADL
                    // 4. Parse log files from games that output FPS
                    
                    return 0f;
                });
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not get FPS for process {ProcessName}", processName);
                return 0f;
            }
        }

        private GameInfo? DetectGameFromPath(string filePath, Process process)
        {
            try
            {
                // First check configured game root folders
                var gameFromRootFolder = DetectGameFromRootFolders(filePath, process);
                if (gameFromRootFolder != null)
                {
                    return gameFromRootFolder;
                }

                // Check each configured game platform path
                foreach (var platformPath in _settings.GamePlatformPaths)
                {
                    if (filePath.Contains(platformPath, StringComparison.OrdinalIgnoreCase))
                    {
                        var platform = GetPlatformFromPath(platformPath);
                        var gameName = ExtractGameNameFromPath(filePath, platformPath);

                        return new GameInfo
                        {
                            GameName = gameName,
                            ExecutableName = Path.GetFileName(filePath),
                            FullPath = filePath,
                            ProcessId = process.Id,
                            MemoryUsage = (ulong)process.WorkingSet64,
                            CpuTime = process.TotalProcessorTime,
                            StartTime = process.StartTime,
                            Platform = platform,
                            IsFullscreen = false, // Will be set by caller
                            FPS = 0f // Will be set by caller
                        };
                    }
                }

                // Additional checks for common game launchers and executables
                var fileName = Path.GetFileNameWithoutExtension(filePath).ToLowerInvariant();
                
                // Exclude known system processes and applications
                var systemExclusions = new[]
                {
                    "officeclicktorun", "winword", "excel", "powerpoint", "outlook",
                    "teams", "skype", "chrome", "firefox", "edge", "explorer",
                    "notepad", "calculator", "cmd", "powershell", "taskmgr",
                    "svchost", "dwm", "csrss", "winlogon", "lsass", "services",
                    "wininit", "audiodg", "conhost", "rundll32", "msiexec",
                    "setup", "installer", "update", "vshost", "devenv"
                };

                // Skip if it's a known system process
                if (systemExclusions.Any(exclusion => fileName.Contains(exclusion)))
                {
                    return null;
                }

                var knownGameExecutables = new[]
                {
                    "game", "launcher", "client"
                    // Removed generic terms like "main", "start", "run" that match too many system processes
                };

                var gameIndicators = new[]
                {
                    "unreal", "unity", "godot", "gamemaker", "rpgmaker",
                    "steam", "epic", "origin", "uplay", "battle.net"
                };

                // Check if it's likely a game based on executable name or path
                // Made the condition more restrictive to reduce false positives
                if ((knownGameExecutables.Any(exe => fileName.Equals(exe) || fileName.StartsWith(exe + ".")) ||
                     gameIndicators.Any(indicator => filePath.Contains(indicator, StringComparison.OrdinalIgnoreCase))) &&
                    !filePath.Contains("Program Files\\Common Files", StringComparison.OrdinalIgnoreCase))
                {
                    // Try to determine platform and game name from other indicators
                    var platform = DeterminePlatformFromProcess(process, filePath);
                    var gameName = DetermineGameNameFromProcess(process, filePath);

                    if (!string.IsNullOrEmpty(gameName))
                    {
                        return new GameInfo
                        {
                            GameName = gameName,
                            ExecutableName = Path.GetFileName(filePath),
                            FullPath = filePath,
                            ProcessId = process.Id,
                            MemoryUsage = (ulong)process.WorkingSet64,
                            CpuTime = process.TotalProcessorTime,
                            StartTime = process.StartTime,
                            Platform = platform,
                            IsFullscreen = false,
                            FPS = 0f
                        };
                    }
                }

                return null;
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Error detecting game from path {FilePath}", filePath);
                return null;
            }
        }

        private string GetPlatformFromPath(string platformPath)
        {
            return platformPath.ToLowerInvariant() switch
            {
                var path when path.Contains("steamapps") => "Steam",
                var path when path.Contains("epic games") => "Epic Games Store",
                var path when path.Contains("gog galaxy") => "GOG Galaxy",
                var path when path.Contains("origin games") => "EA Origin",
                var path when path.Contains("ubisoft game launcher") => "Ubisoft Connect",
                _ => "Unknown"
            };
        }

        private string ExtractGameNameFromPath(string filePath, string platformPath)
        {
            try
            {
                var parts = filePath.Split(new[] { platformPath }, StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length > 1)
                {
                    var gamePath = parts[1];
                    var gameFolder = gamePath.Split(Path.DirectorySeparatorChar, StringSplitOptions.RemoveEmptyEntries)[0];
                    return gameFolder;
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not extract game name from path {FilePath}", filePath);
            }

            return Path.GetFileNameWithoutExtension(filePath);
        }

        private string DeterminePlatformFromProcess(Process process, string filePath)
        {
            try
            {
                // Check parent processes for launcher indicators
                var currentProcess = process;
                for (int i = 0; i < 3; i++) // Check up to 3 levels up
                {
                    try
                    {
                        var parentId = GetParentProcessId(currentProcess.Id);
                        if (parentId == 0) break;

                        var parentProcess = Process.GetProcessById(parentId);
                        var parentName = parentProcess.ProcessName.ToLowerInvariant();

                        if (parentName.Contains("steam"))
                            return "Steam";
                        if (parentName.Contains("epic"))
                            return "Epic Games Store";
                        if (parentName.Contains("origin"))
                            return "EA Origin";
                        if (parentName.Contains("uplay") || parentName.Contains("ubisoft"))
                            return "Ubisoft Connect";
                        if (parentName.Contains("gog"))
                            return "GOG Galaxy";

                        currentProcess = parentProcess;
                    }
                    catch
                    {
                        break;
                    }
                }

                // Fallback: check file path for platform indicators
                if (filePath.Contains("Program Files (x86)"))
                    return "Windows Store/Other";
                if (filePath.Contains("WindowsApps"))
                    return "Microsoft Store";

                return "Standalone";
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not determine platform for process {ProcessName}", process.ProcessName);
                return "Unknown";
            }
        }

        private string DetermineGameNameFromProcess(Process process, string filePath)
        {
            try
            {
                // Try to get a meaningful name from various sources
                
                // 1. Try from file properties
                var versionInfo = FileVersionInfo.GetVersionInfo(filePath);
                if (!string.IsNullOrEmpty(versionInfo.ProductName) && 
                    !versionInfo.ProductName.Equals(versionInfo.FileName, StringComparison.OrdinalIgnoreCase))
                {
                    return versionInfo.ProductName;
                }

                // 2. Try from directory name
                var directory = Path.GetDirectoryName(filePath);
                if (!string.IsNullOrEmpty(directory))
                {
                    var directoryName = Path.GetFileName(directory);
                    if (!string.IsNullOrEmpty(directoryName) && 
                        !directoryName.Equals("bin", StringComparison.OrdinalIgnoreCase) &&
                        !directoryName.Equals("exe", StringComparison.OrdinalIgnoreCase))
                    {
                        return directoryName;
                    }
                }

                // 3. Fallback to executable name
                return Path.GetFileNameWithoutExtension(filePath);
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not determine game name for process {ProcessName}", process.ProcessName);
                return process.ProcessName;
            }
        }

        private GameInfo? DetectGameFromRootFolders(string filePath, Process process)
        {
            try
            {
                foreach (var rootFolder in _settings.GameRootFolders)
                {
                    if (filePath.StartsWith(rootFolder, StringComparison.OrdinalIgnoreCase))
                    {
                        var gameName = ExtractGameNameFromRootFolder(filePath, rootFolder);
                        
                        return new GameInfo
                        {
                            GameName = gameName,
                            ExecutableName = Path.GetFileName(filePath),
                            FullPath = filePath,
                            ProcessId = process.Id,
                            MemoryUsage = (ulong)process.WorkingSet64,
                            CpuTime = process.TotalProcessorTime,
                            StartTime = process.StartTime,
                            Platform = "Standalone", // Games in root folders are typically standalone
                            IsFullscreen = false, // Will be set by caller
                            FPS = 0f // Will be set by caller
                        };
                    }
                }

                return null;
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Error detecting game from root folders for path {FilePath}", filePath);
                return null;
            }
        }

        private string ExtractGameNameFromRootFolder(string filePath, string rootFolder)
        {
            try
            {
                // Remove the root folder from the path to get the relative game path
                var relativePath = filePath.Substring(rootFolder.Length).TrimStart('\\', '/');
                
                // Split by directory separator and take the first part as the game folder
                var pathParts = relativePath.Split(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }, 
                    StringSplitOptions.RemoveEmptyEntries);
                
                if (pathParts.Length > 0)
                {
                    var gameFolder = pathParts[0];
                    
                    // If the game folder name is reasonable, use it
                    if (!string.IsNullOrEmpty(gameFolder) && 
                        !gameFolder.Equals("bin", StringComparison.OrdinalIgnoreCase) &&
                        !gameFolder.Equals("exe", StringComparison.OrdinalIgnoreCase) &&
                        !gameFolder.Equals("data", StringComparison.OrdinalIgnoreCase))
                    {
                        return gameFolder;
                    }
                }

                // Fallback: try to get the game name from file properties
                var versionInfo = FileVersionInfo.GetVersionInfo(filePath);
                if (!string.IsNullOrEmpty(versionInfo.ProductName) && 
                    !versionInfo.ProductName.Equals(versionInfo.FileName, StringComparison.OrdinalIgnoreCase))
                {
                    return versionInfo.ProductName;
                }

                // Last resort: use the executable name
                return Path.GetFileNameWithoutExtension(filePath);
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Could not extract game name from root folder path {FilePath}", filePath);
                return Path.GetFileNameWithoutExtension(filePath);
            }
        }

        private int GetParentProcessId(int processId)
        {
            try
            {
                using var searcher = new System.Management.ManagementObjectSearcher(
                    $"SELECT ParentProcessId FROM Win32_Process WHERE ProcessId = {processId}");
                using var collection = searcher.Get();
                foreach (System.Management.ManagementObject obj in collection)
                {
                    return Convert.ToInt32(obj["ParentProcessId"]);
                }
            }
            catch (Exception ex)
            {
                _logger.LogTrace(ex, "Could not get parent process ID for {ProcessId}", processId);
            }
            return 0;
        }
    }
}