using System.Threading.Tasks;
using System.Reflection;
using Discord.Commands;
using Discord.WebSocket;
using Discord;

namespace MyBot
{
    public class CommandHandler
    {
        private CommandService commands;
        private DiscordSocketClient client;
        private IDependencyMap map;

        public async Task Install(IDependencyMap _map)
        {
            //Create Command Service, Inject it into Dependency Map
            client = _map.Get<DiscordSocketClient>();
            commands = new CommandService();
            _map.Add(commands);
            map = _map;

            await commands.AddModulesAsync(Assembly.GetEntryAssembly());

            //Send user message to get handled
            client.MessageReceived += HandleCommand;

           client.UserJoined += AnnounceJoinUser;
           client.UserLeft += AnnounceLeftUser;
        }

        public async Task AnnounceLeftUser(SocketGuildUser user)
        {
            var channel = client.GetChannel() as SocketTextChannel;

            await channel.SendMessageAsync("");
        }

        public async Task AnnounceJoinUser(SocketGuildUser user)
        {
            var channel = client.GetChannel() as SocketTextChannel;

            await channel.SendMessageAsync("");
        }

        public async Task HandleCommand(SocketMessage parameterMessage)
        {
            //Don't handle the command if it is a system message
            var message = parameterMessage as SocketUserMessage;
            if (message == null) return;

            //Mark where the prefix ends and the command begins
            int argPos = 0;
            //Determine if the message has a valid prefix, adjust argPos
            if (!(message.HasMentionPrefix(client.CurrentUser, ref argPos) || message.HasCharPrefix('!', ref argPos))) return;

            //Create a Command Context
            var context = new CommandContext(client, message);
            //Execute the command, store the result
            var result = await commands.ExecuteAsync(context, argPos, map);

            //If the command failed, notify the user
            if (!result.IsSuccess)
                await message.Channel.SendMessageAsync($"**Error:** {result.ErrorReason}");
        }

    }
}