Flow.Launcher/Flow.Launcher.Core/Plugin/PluginsLoader.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using System.Windows.Forms;
using Droplex;
using Flow.Launcher.Infrastructure;
using Flow.Launcher.Infrastructure.Logger;
using Flow.Launcher.Infrastructure.UserSettings;
using Flow.Launcher.Plugin;
using Flow.Launcher.Plugin.SharedCommands;
using Stopwatch = Flow.Launcher.Infrastructure.Stopwatch;

namespace Flow.Launcher.Core.Plugin
{
    public static class PluginsLoader
    {
        public const string PythonExecutable = "pythonw.exe";

        public static List<PluginPair> Plugins(List<PluginMetadata> metadatas, PluginsSettings settings)
        {
            var dotnetPlugins = DotNetPlugins(metadatas);
            var pythonPlugins = PythonPlugins(metadatas, settings);
            var executablePlugins = ExecutablePlugins(metadatas);
            var plugins = dotnetPlugins.Concat(pythonPlugins).Concat(executablePlugins).ToList();
            return plugins;
        }

        public static IEnumerable<PluginPair> DotNetPlugins(List<PluginMetadata> source)
        {
            var erroredPlugins = new List<string>();

            var plugins = new List<PluginPair>();
            var metadatas = source.Where(o => AllowedLanguage.IsDotNet(o.Language));

            foreach (var metadata in metadatas)
            {
                var milliseconds = Stopwatch.Debug(
                    $"|PluginsLoader.DotNetPlugins|Constructor init cost for {metadata.Name}", () =>
                    {
                        Assembly assembly = null;
                        IAsyncPlugin plugin = null;

                        try
                        {
                            var assemblyLoader = new PluginAssemblyLoader(metadata.ExecuteFilePath);
                            assembly = assemblyLoader.LoadAssemblyAndDependencies();

                            var type = assemblyLoader.FromAssemblyGetTypeOfInterface(assembly,
                                typeof(IAsyncPlugin));

                            plugin = Activator.CreateInstance(type) as IAsyncPlugin;
                        }
#if DEBUG
                        catch (Exception e)
                        {
                            throw;
                        }
#else
                        catch (Exception e) when (assembly == null)
                        {
                            Log.Exception($"|PluginsLoader.DotNetPlugins|Couldn't load assembly for the plugin: {metadata.Name}", e);
                        }
                        catch (InvalidOperationException e)
                        {
                            Log.Exception($"|PluginsLoader.DotNetPlugins|Can't find the required IPlugin interface for the plugin: <{metadata.Name}>", e);
                        }
                        catch (ReflectionTypeLoadException e)
                        {
                            Log.Exception($"|PluginsLoader.DotNetPlugins|The GetTypes method was unable to load assembly types for the plugin: <{metadata.Name}>", e);
                        }
                        catch (Exception e)
                        {
                            Log.Exception($"|PluginsLoader.DotNetPlugins|The following plugin has errored and can not be loaded: <{metadata.Name}>", e);
                        }
#endif

                        if (plugin == null)
                        {
                            erroredPlugins.Add(metadata.Name);
                            return;
                        }

                        plugins.Add(new PluginPair {Plugin = plugin, Metadata = metadata});
                    });
                metadata.InitTime += milliseconds;
            }

            if (erroredPlugins.Count > 0)
            {
                var errorPluginString = String.Join(Environment.NewLine, erroredPlugins);

                var errorMessage = "The following "
                                   + (erroredPlugins.Count > 1 ? "plugins have " : "plugin has ")
                                   + "errored and cannot be loaded:";

                _ = Task.Run(() =>
                {
                    MessageBox.Show($"{errorMessage}{Environment.NewLine}{Environment.NewLine}" +
                                    $"{errorPluginString}{Environment.NewLine}{Environment.NewLine}" +
                                    $"Please refer to the logs for more information", "",
                        MessageBoxButtons.OK, MessageBoxIcon.Warning);
                });
            }

            return plugins;
        }

        public static IEnumerable<PluginPair> PythonPlugins(List<PluginMetadata> source, PluginsSettings settings)
        {
            if (!source.Any(o => o.Language.ToUpper() == AllowedLanguage.Python))
                return new List<PluginPair>();

            if (!string.IsNullOrEmpty(settings.PythonDirectory) && FilesFolders.LocationExists(settings.PythonDirectory))
                return SetPythonPathForPluginPairs(source, Path.Combine(settings.PythonDirectory, PythonExecutable));

            var pythonPath = string.Empty;
            
            if (MessageBox.Show("Flow detected you have installed Python plugins, which " +
                                "will need Python to run. Would you like to download Python? " +
                                Environment.NewLine + Environment.NewLine +
                                "Click no if it's already installed, " +
                                "and you will be prompted to select the folder that contains the Python executable",
                    string.Empty, MessageBoxButtons.YesNo) == DialogResult.No
                && string.IsNullOrEmpty(settings.PythonDirectory))
            {
                var dlg = new FolderBrowserDialog
                {
                    SelectedPath = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles)
                };

                var result = dlg.ShowDialog();
                if (result == DialogResult.OK)
                {
                    string pythonDirectory = dlg.SelectedPath;
                    if (!string.IsNullOrEmpty(pythonDirectory))
                    {
                        pythonPath = Path.Combine(pythonDirectory, PythonExecutable);
                        if (File.Exists(pythonPath))
                        {
                            settings.PythonDirectory = pythonDirectory;
                            Constant.PythonPath = pythonPath;
                        }
                        else
                        {
                            MessageBox.Show("Can't find python in given directory");
                        }
                    }
                }
            }
            else
            {
                var installedPythonDirectory = Path.Combine(DataLocation.DataDirectory(), "PythonEmbeddable");

                // Python 3.8.9 is used for Windows 7 compatibility
                DroplexPackage.Drop(App.python_3_8_9_embeddable, installedPythonDirectory).Wait();

                pythonPath = Path.Combine(installedPythonDirectory, PythonExecutable);
                if (FilesFolders.FileExists(pythonPath))
                {
                    settings.PythonDirectory = installedPythonDirectory;
                    Constant.PythonPath = pythonPath;
                }
                else
                {
                    Log.Error("PluginsLoader",
                        $"Failed to set Python path after Droplex install, {pythonPath} does not exist",
                        "PythonPlugins");
                }
            }

            if (string.IsNullOrEmpty(settings.PythonDirectory) || string.IsNullOrEmpty(pythonPath))
            {
                MessageBox.Show(
                    "Unable to set Python executable path, please try from Flow's settings (scroll down to the bottom).");
                Log.Error("PluginsLoader",
                    $"Not able to successfully set Python path, the PythonDirectory variable is still an empty string.",
                    "PythonPlugins");

                return new List<PluginPair>();
            }

            return SetPythonPathForPluginPairs(source, pythonPath);
        }

        private static IEnumerable<PluginPair> SetPythonPathForPluginPairs(List<PluginMetadata> source, string pythonPath)
            =>  source
                .Where(o => o.Language.ToUpper() == AllowedLanguage.Python)
                .Select(metadata => new PluginPair
                {
                    Plugin = new PythonPlugin(pythonPath), 
                    Metadata = metadata
                })
                .ToList();

    public static IEnumerable<PluginPair> ExecutablePlugins(IEnumerable<PluginMetadata> source)
        {
            return source
                .Where(o => o.Language.ToUpper() == AllowedLanguage.Executable)
                .Select(metadata => new PluginPair
                {
                    Plugin = new ExecutablePlugin(metadata.ExecuteFilePath), Metadata = metadata
                });
        }
    }
}