using System;
using System.Collections.Generic;
using global::System.IO;

namespace Pilz.Reflection.PluginSystem
{
    public class PluginManager
    {

        /// <summary>
    /// The name of the type where to search for Methods when loading a new Plugin.
    /// </summary>
    /// <returns></returns>
        public string EntryTypeName { get; set; } = "Plugin";

        /// <summary>
    /// If true, all MainMethods of a Plugin will be called as soon as a Plugin is loaded.
    /// </summary>
    /// <returns></returns>
        public bool AutoCallMainFunctions { get; set; } = true;

        /// <summary>
    /// A collection of all loaded Plugins.
    /// </summary>
    /// <returns></returns>
        public Dictionary<string, Plugin> Plugins { get; private set; } = new Dictionary<string, Plugin>();

        /// <summary>
    /// Loads Plugins that can be found at the given path and adds them to the Plugins-List.
    /// </summary>
    /// <param name="pluginPath">The path where to search for Plugins to load.</param>
        public IEnumerable<Plugin> LoadPlugins(string pluginPath)
        {
            return LoadPlugins(pluginPath, true);
        }

        /// <summary>
    /// Loads Plugins that can be found at the given path and adds them to the Plugins-List.
    /// </summary>
    /// <param name="pluginPath">The path where to search for Plugins to load.</param>
    /// <param name="addToList">If true, the Plugins will be added to Plugins-List after loading.</param>
        public IEnumerable<Plugin> LoadPlugins(string pluginPath, bool addToList)
        {
            return LoadPlugins(pluginPath, addToList, AutoCallMainFunctions, EntryTypeName);
        }

        /// <summary>
    /// Loads Plugins that can be found at the given path and adds them to the Plugins-List.
    /// </summary>
    /// <param name="pluginPath">The path where to search for Plugins to load.</param>
    /// <param name="addToList">If true, the Plugins will be added to Plugins-List after loading.</param>
    /// <param name="autoCallMainFunction">If true, all MainMethods of a Plugin will be called as soon as a Plugin is loaded.</param>
    /// <param name="entryTypeName">The name of the type where to search for Methods when loading a new Plugin.</param>
        public IEnumerable<Plugin> LoadPlugins(string pluginPath, bool addToList, bool autoCallMainFunction, string entryTypeName)
        {
            var loaded = new List<Plugin>();
            foreach (string f in Directory.GetFiles(pluginPath, "*.dll", SearchOption.AllDirectories))
            {
                var p = LoadPlugin(f, addToList);
                if (p is object)
                {
                    loaded.Add(p);
                }
            }

            return loaded;
        }

        /// <summary>
    /// Loads a Plugin and adds it to the Plugins-List.
    /// </summary>
    /// <param name="filePath">The path to the plugin to load.</param>
    /// <param name="addToList">If true, the Plugin will be added to Plugins-List after loading.</param>
        public Plugin LoadPlugin(string filePath, bool addToList)
        {
            return LoadPlugin(filePath, addToList, AutoCallMainFunctions, EntryTypeName);
        }

        /// <summary>
    /// Loads a Plugin and adds it to the Plugins-List.
    /// </summary>
    /// <param name="filePath">The path to the plugin to load.</param>
    /// <param name="addToList">If true, the Plugin will be added to Plugins-List after loading.</param>
    /// <param name="autoCallMainFunction">If true, all MainMethods of a Plugin will be called as soon as a Plugin is loaded.</param>
    /// <param name="entryTypeName">The name of the type where to search for Methods when loading a new Plugin.</param>
        public Plugin LoadPlugin(string filePath, bool addToList, bool autoCallMainFunction, string entryTypeName)
        {
            try
            {
                var plugin = new Plugin(filePath, autoCallMainFunction, entryTypeName);
                if (addToList)
                    Plugins.Add(filePath, plugin);
                return plugin;
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
    /// Loads a Plugin and adds it to the Plugins-List.
    /// </summary>
    /// <param name="filePath">The path to the plugin to load.</param>
        public Plugin LoadPlugin(string filePath)
        {
            return LoadPlugin(filePath, true);
        }

        /// <summary>
    /// Get all PluginFunctions that have one of the given function codes.
    /// </summary>
    /// <param name="funcCodes"></param>
    /// <returns></returns>
        public IEnumerable<PluginFunction> GetFunctions(params string[] funcCodes)
        {
            var list = new List<PluginFunction>();
            foreach (var kvp in Plugins)
                list.AddRange(kvp.Value.GetFunctions(funcCodes));
            return list;
        }

        /// <summary>
    /// Get the first PluginFunction that have the one of the given function codes.
    /// </summary>
    /// <returns></returns>
        public PluginFunction GetFunction(params string[] funcCodes)
        {
            PluginFunction f = null;
            foreach (var kvp in Plugins)
            {
                if (f is null)
                {
                    foreach (PluginFunction func in kvp.Value.GetFunctions(funcCodes))
                    {
                        if (f is null)
                        {
                            f = func;
                        }
                    }
                }
            }

            return f;
        }
    }
}