using Discord;
using Discord.WebSocket;
using System.Reflection;

namespace MinecraftDiscordBot;

public abstract class CommandRouter<T> : ICommandHandler<T> {
    private readonly Dictionary<string, HandleCommandDelegate<T>> _handlers = new();
    public CommandRouter() {
        foreach (var method in GetType().GetMethods())
            if (GetHandlerAttribute(method) is CommandHandlerAttribute handler)
                try {
                    _handlers.Add(handler.CommandName, method.CreateDelegate<HandleCommandDelegate<T>>(this));
                } catch (Exception) {
                    Program.LogWarning("CommandRouter", $"Could not add delegate for method {handler.CommandName} in function {method.ReturnType} {method.Name}(...)!");
                    throw;
                }
    }

    private static CommandHandlerAttribute? GetHandlerAttribute(MethodInfo method)
        => method.GetCustomAttributes(typeof(CommandHandlerAttribute), true).OfType<CommandHandlerAttribute>().FirstOrDefault();
    public abstract Task<T> RootAnswer(SocketUserMessage message, CancellationToken ct);
    public abstract Task<T> FallbackHandler(SocketUserMessage message, string method, string[] parameters, CancellationToken ct);
    public Task<T> HandleCommand(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => parameters is { Length: 0 }
            ? RootAnswer(message, ct)
            : _handlers.TryGetValue(parameters[0], out var handler)
                ? handler(message, parameters[1..], ct)
                : FallbackHandler(message, parameters[0], parameters[1..], ct);
}