using System.Diagnostics;
using Microsoft.Win32;

namespace CVRManager.Services;

public static class SteamIntegration
{
    public static string? SteamPath
    {
        get
        {
            var p = Registry.GetValue(@"HKEY_CURRENT_USER\Software\Valve\Steam", "SteamPath", null) as string;
            return p == null ? null : Path.GetFullPath(p);
        }
    }

    public static string? SteamExe => SteamPath is { } p ? Path.Combine(p, "steam.exe") : null;

    public static bool IsRunning => Process.GetProcessesByName("steam").Length > 0;

    public static bool IsAppRunning =>
        Registry.GetValue($@"HKEY_CURRENT_USER\Software\Valve\Steam\Apps\{Paths.AppId}", "Running", 0) is 1;

    public static async Task<bool> EnsureRunningAsync(Action<string> log)
    {
        if (IsRunning) return true;
        var exe = SteamExe;
        if (exe == null || !File.Exists(exe)) return false;
        log("Steam is not running; starting it in the background so playtime is counted...");
        Process.Start(new ProcessStartInfo(exe, "-silent") { UseShellExecute = true });
        for (var i = 0; i < 40; i++)
        {
            await Task.Delay(500);
            var pid = Registry.GetValue(@"HKEY_CURRENT_USER\Software\Valve\Steam\ActiveProcess", "pid", 0) as int? ?? 0;
            if (pid != 0 && IsRunning) { await Task.Delay(2000); return true; }
        }
        return IsRunning;
    }

    public static List<(string GameDir, string Manifest)> FindExistingInstalls()
    {
        var result = new List<(string, string)>();
        var steam = SteamPath;
        if (steam == null) return result;
        var libs = new List<string> { steam };
        try
        {
            var vdf = Path.Combine(steam, "steamapps", "libraryfolders.vdf");
            if (File.Exists(vdf))
            {
                var doc = Vdf.ParseDocument(File.ReadAllText(vdf));
                if (doc.Dict("libraryfolders") is { } lf)
                    foreach (var e in lf.Values.OfType<Dictionary<string, object>>())
                        if (e.Str("path") is { Length: > 0 } p) libs.Add(p);
            }
        }
        catch { }

        foreach (var lib in libs.Distinct(StringComparer.OrdinalIgnoreCase))
        {
            var manifest = Path.Combine(lib, "steamapps", $"appmanifest_{Paths.AppId}.acf");
            if (!File.Exists(manifest)) continue;
            try
            {
                var dir = Vdf.ParseDocument(File.ReadAllText(manifest)).Dict("AppState")?.Str("installdir") ?? "ChilloutVR";
                var game = Path.Combine(lib, "steamapps", "common", dir);
                if (Directory.Exists(game)) result.Add((game, manifest));
            }
            catch { }
        }
        return result;
    }
}