PowerToys/src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WebSearch/Helpers/DefaultBrowserInfo.cs

// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using ManagedCommon;

namespace Microsoft.CmdPal.Ext.WebSearch.Helpers;

/// <summary>
/// Contains information (e.g. path to executable, name...) about the default browser.
/// </summary>
public static class DefaultBrowserInfo
{
    private static readonly Lock _updateLock = new();

    /// <summary>Gets the path to the MS Edge browser executable.</summary>
    public static string MSEdgePath => System.IO.Path.Combine(
        Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86),
        @"Microsoft\Edge\Application\msedge.exe");

    /// <summary>Gets the command line pattern of the MS Edge.</summary>
    public const string MSEdgeArgumentsPattern = "--single-argument %1";

    public const string MSEdgeName = "Microsoft Edge";

    /// <summary>Gets the path to default browser's executable.</summary>
    public static string? Path { get; private set; }

    /// <summary>Gets <see cref="Path"/> since the icon is embedded in the executable.</summary>
    public static string? IconPath => Path;

    /// <summary>Gets the user-friendly name of the default browser.</summary>
    public static string? Name { get; private set; }

    /// <summary>Gets the command line pattern of the default browser.</summary>
    public static string? ArgumentsPattern { get; private set; }

    public static bool IsDefaultBrowserSet => !string.IsNullOrEmpty(Path);

    public const long UpdateTimeout = 300;

    private static long _lastUpdateTickCount = -UpdateTimeout;

    private static bool _updatedOnce;
    private static bool _errorLogged;

    /// <summary>
    /// Updates only if at least more than 300ms has passed since the last update, to avoid multiple calls to <see cref="Update"/>.
    /// (because of multiple plugins calling update at the same time.)
    /// </summary>
    public static void UpdateIfTimePassed()
    {
        var curTickCount = Environment.TickCount64;
        if (curTickCount - _lastUpdateTickCount >= UpdateTimeout)
        {
            _lastUpdateTickCount = curTickCount;
            Update();
        }
    }

    /// <summary>
    /// Consider using <see cref="UpdateIfTimePassed"/> to avoid updating multiple times.
    /// (because of multiple plugins calling update at the same time.)
    /// </summary>
    public static void Update()
    {
        lock (_updateLock)
        {
            if (!_updatedOnce)
            {
                // Log.Info("I've tried updating the chosen Web Browser info at least once.", typeof(DefaultBrowserInfo));
                _updatedOnce = true;
            }

            try
            {
                var progId = GetRegistryValue(
                    @"HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Associations\UrlAssociations\http\UserChoice",
                    "ProgId");
                var appName = GetRegistryValue($@"HKEY_CLASSES_ROOT\{progId}\Application", "ApplicationName")
                    ?? GetRegistryValue($@"HKEY_CLASSES_ROOT\{progId}", "FriendlyTypeName");

                if (appName != null)
                {
                    // Handle indirect strings:
                    if (appName.StartsWith('@'))
                    {
                        appName = GetIndirectString(appName);
                    }

                    appName = appName
                        .Replace("URL", null, StringComparison.OrdinalIgnoreCase)
                        .Replace("HTML", null, StringComparison.OrdinalIgnoreCase)
                        .Replace("Document", null, StringComparison.OrdinalIgnoreCase)
                        .Replace("Web", null, StringComparison.OrdinalIgnoreCase)
                        .TrimEnd();
                }

                Name = appName;

                var commandPattern = GetRegistryValue($@"HKEY_CLASSES_ROOT\{progId}\shell\open\command", null);

                if (string.IsNullOrEmpty(commandPattern))
                {
                    throw new ArgumentOutOfRangeException(
                        nameof(commandPattern),
                        "Default browser program command is not specified.");
                }

                if (commandPattern.StartsWith('@'))
                {
                    commandPattern = GetIndirectString(commandPattern);
                }

                // HACK: for firefox installed through Microsoft store
                // When installed through Microsoft Firefox the commandPattern does not have
                // quotes for the path. As the Program Files does have a space
                // the extracted path would be invalid, here we add the quotes to fix it
                const string FirefoxExecutableName = "firefox.exe";
                if (commandPattern.Contains(FirefoxExecutableName) && commandPattern.Contains(@"\WindowsApps\") && (!commandPattern.StartsWith('\"')))
                {
                    var pathEndIndex = commandPattern.IndexOf(FirefoxExecutableName, StringComparison.Ordinal) + FirefoxExecutableName.Length;
                    commandPattern = commandPattern.Insert(pathEndIndex, "\"");
                    commandPattern = commandPattern.Insert(0, "\"");
                }

                if (commandPattern.StartsWith('\"'))
                {
                    var endQuoteIndex = commandPattern.IndexOf('\"', 1);
                    if (endQuoteIndex != -1)
                    {
                        Path = commandPattern.Substring(1, endQuoteIndex - 1);
                        ArgumentsPattern = commandPattern.Substring(endQuoteIndex + 1).Trim();
                    }
                }
                else
                {
                    var spaceIndex = commandPattern.IndexOf(' ');
                    if (spaceIndex != -1)
                    {
                        Path = commandPattern.Substring(0, spaceIndex);
                        ArgumentsPattern = commandPattern.Substring(spaceIndex + 1).Trim();
                    }
                }

                // Packaged applications could be an URI. Example: shell:AppsFolder\Microsoft.MicrosoftEdge.Stable_8wekyb3d8bbwe!App
                if (!System.IO.Path.Exists(Path) && !Uri.TryCreate(Path, UriKind.Absolute, out _))
                {
                    throw new ArgumentException(
                        $"Command validation failed: {commandPattern}",
                        nameof(commandPattern));
                }

                if (string.IsNullOrEmpty(Path))
                {
                    throw new ArgumentOutOfRangeException(
                        nameof(Path),
                        "Default browser program path could not be determined.");
                }
            }
            catch (Exception)
            {
                // Fallback to MS Edge
                Path = MSEdgePath;
                Name = MSEdgeName;
                ArgumentsPattern = MSEdgeArgumentsPattern;

                if (!_errorLogged)
                {
                    // Log.Exception("Exception when retrieving browser path/name. Path and Name are set to use Microsoft Edge.", e, typeof(DefaultBrowserInfo));
                    Logger.LogError("Exception when retrieving browser path/name. Path and Name are set to use Microsoft Edge.");
                    _errorLogged = true;
                }
            }

            string? GetRegistryValue(string registryLocation, string? valueName)
            {
                return Microsoft.Win32.Registry.GetValue(registryLocation, valueName, null) as string;
            }

            string GetIndirectString(string str)
            {
                var stringBuilder = new StringBuilder(128);
                unsafe
                {
                    var buffer = stackalloc char[128];
                    var capacity = 128;
                    var firstChar = str[0];
                    var strPtr = &firstChar;

                    // S_OK == 0
                    fixed (char* pszSourceLocal = str)
                    {
                        if (global::Windows.Win32.PInvoke.SHLoadIndirectString(
                            pszSourceLocal,
                            buffer,
                            (uint)capacity,
                            default) == 0)
                        {
                            return new string(buffer);
                        }
                    }
                }

                throw new ArgumentNullException(nameof(str), "Could not load indirect string.");
            }
        }
    }
}