using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;

namespace SlamCross.Services;

public static class GameLocatorService
{
    public static string? FindSteamAppsPath(string exeName)
    {
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            return FindSteamAppsLinux(exeName);
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            return FindSteamAppsWindows(exeName);
        return null;
    }

    private static string? FindSteamAppsLinux(string exeName)
    {
        try
        {
            var proc = Process.GetProcessesByName(exeName).FirstOrDefault();
            if (proc?.MainModule?.FileName is string exe)
            {
                var dir = Path.GetDirectoryName(exe);
                while (dir != null)
                {
                    if (Path.GetFileName(dir) == "steamapps")
                        return dir;
                    dir = Path.GetDirectoryName(dir);
                }
            }
        }
        catch { }

        var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
        string[] candidates =
        [
            Path.Combine(home, ".local/share/Steam/steamapps"),
            Path.Combine(home, ".steam/steam/steamapps"),
            "/usr/local/games/steamapps",
        ];
        return candidates.FirstOrDefault(Directory.Exists);
    }

    private static string? FindSteamAppsWindows(string exeName)
    {
        try
        {
            var proc = Process.GetProcessesByName(exeName).FirstOrDefault();
            if (proc?.MainModule?.FileName is string exe)
            {
                var gameDir = "common\\" + GetGameFolderName(exeName) + "\\";
                var idx = exe.IndexOf(gameDir, StringComparison.OrdinalIgnoreCase);
                if (idx >= 0) return exe[..idx];
            }
        }
        catch { }
        return null;
    }

    private static string GetGameFolderName(string exeName) => exeName switch
    {
        "cs2" => "Counter-Strike Global Offensive",
        _ => exeName
    };

}