using System;
using System.Collections.Generic;
using System.Reflection;
using System.Threading.Tasks;
using Discord;
using Discord.WebSocket;
using PluginManager.Interfaces;
using PluginManager.Others;

namespace PluginManager.Loaders;

public class PluginLoader
{
    public delegate void CMDLoaded(string name, string typeName, bool success, Exception? e = null);

    public delegate void EVELoaded(string name, string typeName, bool success, Exception? e = null);

    public delegate void SLSHLoaded(string name, string tyypename, bool success, Exception? e = null);

    private const string pluginFolder = @"./Data/Plugins/";

    internal const   string              pluginExtension = "dll";
    private readonly DiscordSocketClient _client;

    /// <summary>
    ///     Event that is fired when a <see cref="DBCommand" /> is successfully loaded into commands list
    /// </summary>
    public CMDLoaded? onCMDLoad;

    /// <summary>
    ///     Event that is fired when a <see cref="DBEvent" /> is successfully loaded into events list
    /// </summary>
    public EVELoaded? onEVELoad;

    /// <summary>
    ///     Event that is fired when a <see cref="DBEvent" /> is successfully loaded into events list
    /// </summary>
    public SLSHLoaded? onSLSHLoad;

    /// <summary>
    ///     The Plugin Loader constructor
    /// </summary>
    /// <param name="discordSocketClient">The discord bot client where the plugins will pe attached to</param>
    public PluginLoader(DiscordSocketClient discordSocketClient)
    {
        _client = discordSocketClient;
    }


    /// <summary>
    ///     A list of <see cref="DBCommand" /> commands
    /// </summary>
    public static List<DBCommand>? Commands { get; set; }

    /// <summary>
    ///     A list of <see cref="DBEvent" /> commands
    /// </summary>
    public static List<DBEvent>? Events { get; set; }

    /// <summary>
    ///     A list of <see cref="DBSlashCommand" /> commands
    /// </summary>
    public static List<DBSlashCommand>? SlashCommands { get; set; }

    public static int PluginsLoaded
    {
        get
        {
            var count = 0;
            if (Commands is not null)
                count += Commands.Count;
            if (Events is not null)
                count += Events.Count;
            if (SlashCommands is not null)
                count += SlashCommands.Count;
            return count;
        }
    }

    /// <summary>
    ///     The main mathod that is called to load all events
    /// </summary>
    public async void LoadPlugins()
    {
        //Load all plugins

        Commands      = new List<DBCommand>();
        Events        = new List<DBEvent>();
        SlashCommands = new List<DBSlashCommand>();

        Config.Logger.Log("Starting plugin loader ... Client: " + _client.CurrentUser.Username, this,
                          LogLevel.INFO);

        var loader = new Loader("./Data/Plugins", "dll");
        loader.FileLoaded   += args => Config.Logger.Log($"{args.PluginName} file Loaded", this, LogLevel.INFO);
        loader.PluginLoaded += Loader_PluginLoaded;
        var res = loader.Load();
        Events        = res.Item1;
        Commands      = res.Item2;
        SlashCommands = res.Item3;
    }

    private async void Loader_PluginLoaded(LoaderArgs args)
    {
        switch (args.TypeName)
        {
            case "DBCommand":
                onCMDLoad?.Invoke(((DBCommand)args.Plugin!).Command, args.TypeName!, args.IsLoaded, args.Exception);
                break;
            case "DBEvent":
                try
                {
                    if (args.IsLoaded)
                        ((DBEvent)args.Plugin!).Start(_client);

                    onEVELoad?.Invoke(((DBEvent)args.Plugin!).Name, args.TypeName!, args.IsLoaded, args.Exception);
                }
                catch (Exception ex)
                {
                    Config.Logger.Log(ex.Message, this, LogLevel.ERROR);
                }

                break;
            case "DBSlashCommand":
                if (args.IsLoaded)
                {
                    var slash   = (DBSlashCommand)args.Plugin;
                    var builder = new SlashCommandBuilder();
                    builder.WithName(slash.Name);
                    builder.WithDescription(slash.Description);
                    builder.WithDMPermission(slash.canUseDM);
                    builder.Options = slash.Options;

                    onSLSHLoad?.Invoke(((DBSlashCommand)args.Plugin!).Name, args.TypeName, args.IsLoaded,
                                       args.Exception);
                    await _client.CreateGlobalApplicationCommandAsync(builder.Build());
                }

                break;
        }
    }

    public static async Task LoadPluginFromAssembly(Assembly asmb, DiscordSocketClient client)
    {
        var types = asmb.GetTypes();
        foreach (var type in types)
            if (type.IsClass && typeof(DBEvent).IsAssignableFrom(type))
            {
                var instance = (DBEvent)Activator.CreateInstance(type);
                instance.Start(client);
                Events.Add(instance);
                Config.Logger.Log($"[EVENT] Loaded external {type.FullName}!", LogLevel.INFO);
            }
            else if (type.IsClass && typeof(DBCommand).IsAssignableFrom(type))
            {
                var instance = (DBCommand)Activator.CreateInstance(type);
                Commands.Add(instance);
                Config.Logger.Log($"[CMD] Instance: {type.FullName} loaded !", LogLevel.INFO);
            }
            else if (type.IsClass && typeof(DBSlashCommand).IsAssignableFrom(type))
            {
                var instance = (DBSlashCommand)Activator.CreateInstance(type);
                var builder  = new SlashCommandBuilder();
                builder.WithName(instance.Name);
                builder.WithDescription(instance.Description);
                builder.WithDMPermission(instance.canUseDM);
                builder.Options = instance.Options;

                await client.CreateGlobalApplicationCommandAsync(builder.Build());
                SlashCommands.Add(instance);
                Config.Logger.Log($"[SLASH] Instance: {type.FullName} loaded !", LogLevel.INFO);
            }
    }
}