PluginManager.cs

using Flow.Launcher.Core.ExternalPlugins;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Flow.Launcher.Infrastructure;
using Flow.Launcher.Infrastructure.Logger;
using Flow.Launcher.Infrastructure.UserSettings;
using Flow.Launcher.Plugin;
using ISavable = Flow.Launcher.Plugin.ISavable;

namespace Flow.Launcher.Core.Plugin
{
    /// <summary>
    /// The entry for managing Flow Launcher plugins
    /// </summary>
    public static class PluginManager
    {
        private static IEnumerable<PluginPair> _contextMenuPlugins;

        public static List<PluginPair> AllPlugins { get; private set; }
        public static readonly HashSet<PluginPair> GlobalPlugins = new();
        public static readonly Dictionary<string, PluginPair> NonGlobalPlugins = new();

        public static IPublicAPI API { private set; get; }

        // todo happlebao, this should not be public, the indicator function should be embeded 
        public static PluginsSettings Settings;
        private static List<PluginMetadata> _metadatas;

        /// <summary>
        /// Directories that will hold Flow Launcher plugin directory
        /// </summary>
        private static readonly string[] Directories =
        {
            Constant.PreinstalledDirectory, DataLocation.PluginsDirectory
        };

        private static void DeletePythonBinding()
        {
            const string binding = "flowlauncher.py";
            foreach (var subDirectory in Directory.GetDirectories(DataLocation.PluginsDirectory))
            {
                File.Delete(Path.Combine(subDirectory, binding));
            }
        }

        public static void Save()
        {
            foreach (var plugin in AllPlugins)
            {
                var savable = plugin.Plugin as ISavable;
                savable?.Save();
            }

            API.SavePluginSettings();
        }

        public static async ValueTask DisposePluginsAsync()
        {
            foreach (var pluginPair in AllPlugins)
            {
                switch (pluginPair.Plugin)
                {
                    case IDisposable disposable:
                        disposable.Dispose();
                        break;
                    case IAsyncDisposable asyncDisposable:
                        await asyncDisposable.DisposeAsync();
                        break;
                }
            }
        }

        public static async Task ReloadDataAsync()
        {
            await Task.WhenAll(AllPlugins.Select(plugin => plugin.Plugin switch
            {
                IReloadable p => Task.Run(p.ReloadData),
                IAsyncReloadable p => p.ReloadDataAsync(),
                _ => Task.CompletedTask,
            }).ToArray());
        }

        static PluginManager()
        {
            // validate user directory
            Directory.CreateDirectory(DataLocation.PluginsDirectory);
            // force old plugins use new python binding
            DeletePythonBinding();
        }

        /// <summary>
        /// because InitializePlugins needs API, so LoadPlugins needs to be called first
        /// todo happlebao The API should be removed
        /// </summary>
        /// <param name="settings"></param>
        public static void LoadPlugins(PluginsSettings settings)
        {
            _metadatas = PluginConfig.Parse(Directories);
            Settings = settings;
            Settings.UpdatePluginSettings(_metadatas);
            AllPlugins = PluginsLoader.Plugins(_metadatas, Settings);
        }

        /// <summary>
        /// Call initialize for all plugins
        /// </summary>
        /// <returns>return the list of failed to init plugins or null for none</returns>
        public static async Task InitializePluginsAsync(IPublicAPI api)
        {
            API = api;
            var failedPlugins = new ConcurrentQueue<PluginPair>();

            var InitTasks = AllPlugins.Select(pair => Task.Run(async delegate
            {
                try
                {
                    var milliseconds = await Stopwatch.DebugAsync($"|PluginManager.InitializePlugins|Init method time cost for <{pair.Metadata.Name}>",
                        () => pair.Plugin.InitAsync(new PluginInitContext(pair.Metadata, API)));

                    pair.Metadata.InitTime += milliseconds;
                    Log.Info(
                        $"|PluginManager.InitializePlugins|Total init cost for <{pair.Metadata.Name}> is <{pair.Metadata.InitTime}ms>");
                }
                catch (Exception e)
                {
                    Log.Exception(nameof(PluginManager), $"Fail to Init plugin: {pair.Metadata.Name}", e);
                    pair.Metadata.Disabled = true;
                    failedPlugins.Enqueue(pair);
                }
            }));

            await Task.WhenAll(InitTasks);

            _contextMenuPlugins = GetPluginsForInterface<IContextMenu>();
            foreach (var plugin in AllPlugins)
            {
                // set distinct on each plugin's action keywords helps only firing global(*) and action keywords once where a plugin
                // has multiple global and action keywords because we will only add them here once.
                foreach (var actionKeyword in plugin.Metadata.ActionKeywords.Distinct())
                {
                    switch (actionKeyword)
                    {
                        case Query.GlobalPluginWildcardSign:
                            GlobalPlugins.Add(plugin);
                            break;
                        default:
                            NonGlobalPlugins[actionKeyword] = plugin;
                            break;
                    }
                }
            }

            if (failedPlugins.Any())
            {
                var failed = string.Join(",", failedPlugins.Select(x => x.Metadata.Name));
                API.ShowMsg($"Fail to Init Plugins",
                    $"Plugins: {failed} - fail to load and would be disabled, please contact plugin creator for help",
                    "", false);
            }
        }

        public static PluginPair[] ValidPluginsForQuery(Query query)
        {
            if (query is null)
            {
                return Array.Empty<PluginPair>();
            }
            
            string actionKeyword = query.ActionKeyword;
            if (NonGlobalPlugins.TryGetValue(actionKeyword, out var plugin))
            {
                return plugin.Metadata.Disabled ? Array.Empty<PluginPair>() : new[] { plugin };
            }
            else
            {
                return GlobalPlugins.Where(x => !x.Metadata.Disabled).ToArray();
            }
        }

        public static async Task<List<Result>> QueryForPluginAsync(PluginPair pair, Query query, CancellationToken token)
        {
            var results = new List<Result>();
            var metadata = pair.Metadata;

            try
            {
                var milliseconds = await Stopwatch.DebugAsync($"|PluginManager.QueryForPlugin|Cost for {metadata.Name}",
                    async () => results = await pair.Plugin.QueryAsync(query, token).ConfigureAwait(false));

                token.ThrowIfCancellationRequested();
                if (results == null)
                    return null;
                UpdatePluginMetadata(results, metadata, query);

                metadata.QueryCount += 1;
                metadata.AvgQueryTime =
                    metadata.QueryCount == 1 ? milliseconds : (metadata.AvgQueryTime + milliseconds) / 2;
                token.ThrowIfCancellationRequested();
            }
            catch (OperationCanceledException)
            {
                // null will be fine since the results will only be added into queue if the token hasn't been cancelled
                return null;
            }
            catch (Exception e)
            {
                throw new FlowPluginException(metadata, e);
            }
            return results;
        }

        public static void UpdatePluginMetadata(List<Result> results, PluginMetadata metadata, Query query)
        {
            foreach (var r in results)
            {
                r.PluginDirectory = metadata.PluginDirectory;
                r.PluginID = metadata.ID;
                r.OriginQuery = query;

                // ActionKeywordAssigned is used for constructing MainViewModel's query text auto-complete suggestions 
                // Plugins may have multi-actionkeywords eg. WebSearches. In this scenario it needs to be overriden on the plugin level 
                if (metadata.ActionKeywords.Count == 1)
                    r.ActionKeywordAssigned = query.ActionKeyword;
            }
        }

        /// <summary>
        /// get specified plugin, return null if not found
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static PluginPair GetPluginForId(string id)
        {
            return AllPlugins.FirstOrDefault(o => o.Metadata.ID == id);
        }

        public static IEnumerable<PluginPair> GetPluginsForInterface<T>() where T : IFeatures
        {
            return AllPlugins.Where(p => p.Plugin is T);
        }

        public static List<Result> GetContextMenusForPlugin(Result result)
        {
            var results = new List<Result>();
            var pluginPair = _contextMenuPlugins.FirstOrDefault(o => o.Metadata.ID == result.PluginID);
            if (pluginPair != null)
            {
                var plugin = (IContextMenu)pluginPair.Plugin;

                try
                {
                    results = plugin.LoadContextMenus(result) ?? results;
                    foreach (var r in results)
                    {
                        r.PluginDirectory = pluginPair.Metadata.PluginDirectory;
                        r.PluginID = pluginPair.Metadata.ID;
                        r.OriginQuery = result.OriginQuery;
                    }
                }
                catch (Exception e)
                {
                    Log.Exception(
                        $"|PluginManager.GetContextMenusForPlugin|Can't load context menus for plugin <{pluginPair.Metadata.Name}>",
                        e);
                }
            }

            return results;
        }

        public static bool ActionKeywordRegistered(string actionKeyword)
        {
            // this method is only checking for action keywords (defined as not '*') registration
            // hence the actionKeyword != Query.GlobalPluginWildcardSign logic
            return actionKeyword != Query.GlobalPluginWildcardSign
                   && NonGlobalPlugins.ContainsKey(actionKeyword);
        }

        /// <summary>
        /// used to add action keyword for multiple action keyword plugin
        /// e.g. web search
        /// </summary>
        public static void AddActionKeyword(string id, string newActionKeyword)
        {
            var plugin = GetPluginForId(id);
            if (newActionKeyword == Query.GlobalPluginWildcardSign)
            {
                GlobalPlugins.Add(plugin);
            }
            else
            {
                NonGlobalPlugins[newActionKeyword] = plugin;
            }

            plugin.Metadata.ActionKeywords.Add(newActionKeyword);
        }

        /// <summary>
        /// used to remove action keyword for multiple action keyword plugin
        /// e.g. web search
        /// </summary>
        public static void RemoveActionKeyword(string id, string oldActionkeyword)
        {
            var plugin = GetPluginForId(id);
            if (oldActionkeyword == Query.GlobalPluginWildcardSign
                && // Plugins may have multiple ActionKeywords that are global, eg. WebSearch
                plugin.Metadata.ActionKeywords
                    .Count(x => x == Query.GlobalPluginWildcardSign) == 1)
            {
                GlobalPlugins.Remove(plugin);
            }

            if (oldActionkeyword != Query.GlobalPluginWildcardSign)
                NonGlobalPlugins.Remove(oldActionkeyword);


            plugin.Metadata.ActionKeywords.Remove(oldActionkeyword);
        }

        public static void ReplaceActionKeyword(string id, string oldActionKeyword, string newActionKeyword)
        {
            if (oldActionKeyword != newActionKeyword)
            {
                AddActionKeyword(id, newActionKeyword);
                RemoveActionKeyword(id, oldActionKeyword);
            }
        }
    }
}