using Discord.WebSocket;
using Fleck;
using MinecraftDiscordBot.Commands;
using MinecraftDiscordBot.Models;
using Newtonsoft.Json;
using System.Linq;

namespace MinecraftDiscordBot.Services;

public delegate Task<TResponse> HandleCommandDelegate<TResponse>(SocketUserMessage message, string[] parameters, CancellationToken ct);
public delegate Task HandleCommandDelegate(SocketUserMessage message, string[] parameters, CancellationToken ct);

public class RootCommandService : CommandRouter, ITaskWaitSource {
    protected IWebSocketConnection? _socketField;
    public override string HelpTextPrefix => "!";
    public RootCommandService(IUserRoleManager roleManager) : base() {
        RefinedStorage = new RefinedStorageService(this, roleManager);
        Players = new PlayerDetectorService(this);
        Chat = new ChatBoxService(this);
    }

    public static async Task<T> Method<T>(ITaskWaitSource taskSource, string methodName, Func<string, T> parser, CancellationToken ct, Dictionary<string, object>? parameters = null) {
        var waiter = taskSource.GetWaiter(parser, ct);
        await taskSource.Send(new RequestMessage(waiter.ID, methodName, parameters));
        return await waiter.Task;
    }

    public event EventHandler<ChatEvent>? ChatMessageReceived;
    public event EventHandler<PlayerStatusEvent>? PlayerStatusChanged;
    public event EventHandler<PeripheralAttachEvent>? PeripheralAttached;
    public event EventHandler<PeripheralDetachEvent>? PeripheralDetached;
    public event EventHandler<IWebSocketConnection?>? SocketChanged;

    public IWebSocketConnection? Socket {
        get => _socketField; set {
            if (_socketField != value) {
                _socketField = value;
                if (value is not null) value.OnMessage = OnMessage;
                SocketChanged?.Invoke(this, value);
            }
        }
    }

    public RefinedStorageService RefinedStorage { get; }
    public PlayerDetectorService Players { get; }
    public ChatBoxService Chat { get; }

    private void OnMessage(string message) {
        switch (Message.Deserialize(message)) {
        case ChatEvent msg:
            ChatMessageReceived?.Invoke(this, msg);
            break;
        case PlayerStatusEvent msg:
            PlayerStatusChanged?.Invoke(this, msg);
            break;
        case PeripheralAttachEvent msg:
            PeripheralAttached?.Invoke(this, msg);
            break;
        case PeripheralDetachEvent msg:
            PeripheralDetached?.Invoke(this, msg);
            break;
        case ReplyMessage msg:
            IChunkWaiter? waiter;
            lock (_syncRoot) if (!_waits.TryGetValue(msg.AnswerId, out waiter)) {
                    Program.LogWarningAsync("Socket", $"Invalid wait id '{msg.AnswerId}'!");
                    return;
                }
            waiter.SetResultState(msg.State);
            waiter.AddChunk(msg.Chunk, msg.Total, msg.Result);
            if (waiter.Finished || waiter.IsCancellationRequested)
                lock (_syncRoot)
                    _waits.Remove(waiter.ID);
            break;
        default:
            Program.LogInfo(Program.WebSocketSource, $"Received unhandled message: {message}!");
            break;
        }
    }

    public Task Send(string message) => (Socket ?? throw new ReplyException("Minecraft server is not available!")).Send(message);
    public Task Send(Message message) => Send(JsonConvert.SerializeObject(message));
    private readonly object _syncRoot = new();
    private readonly Dictionary<int, IChunkWaiter> _waits = new();
    private readonly Random _rnd = new();

    private int GetFreeId() {
        var attempts = 0;
        while (true) {
            var id = _rnd.Next();
            if (!_waits.ContainsKey(id))
                return id;
            Program.LogWarningAsync(Program.WebSocketSource, $"Could not get a free ID after {++attempts} attempts!");
        }
    }

    public ChunkWaiter<T> GetWaiter<T>(Func<string, T> resultParser, CancellationToken ct) {
        ChunkWaiter<T> waiter;
        lock (_syncRoot) {
            waiter = new ChunkWaiter<T>(GetFreeId(), resultParser, ct);
            _waits.Add(waiter.ID, waiter);
        }
        return waiter;
    }

    public Task<Dictionary<string, Peripheral>> GetPeripherals(CancellationToken ct) => Method(this, "peripherals", Deserialize<Dictionary<string, Peripheral>>(), ct);
    [CommandHandler("rs", HelpText = "Provides some commands for interacting with the Refined Storage system.")]
    public Task<ResponseType> RefinedStorageHandler(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => RefinedStorage.HandleCommand(message, parameters, ct);
    [CommandHandler("peripherals", HelpText = "Gets a list of peripherals that are attached.")]
    public async Task<ResponseType> HandleGetPeripherals(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => ResponseType.AsString(string.Join("\n", (await GetPeripherals(ct)).Values.Select(i => $"On side {i.Side}: {i.Type}")));
    [CommandHandler("pd", HelpText = "Provides some commands for interacting with the Player Detector.")]
    public Task<ResponseType> PlayerDetectorHandler(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => Players.HandleCommand(message, parameters, ct);
    [CommandHandler("chat", HelpText = "Provides some commands for chatting.")]
    public Task<ResponseType> ChatBoxHandler(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => Chat.HandleCommand(message, parameters, ct);

    public static Func<string, T> Deserialize<T>() => msg
             => JsonConvert.DeserializeObject<T>(msg) ?? throw new InvalidProgramException("Empty response!");
    public override Task<ResponseType> FallbackHandler(SocketUserMessage message, string method, string[] parameters, CancellationToken ct)
        => throw new ReplyException($"What the fuck do you mean by '{method}'?");
}

public interface ITaskWaitSource {
    ChunkWaiter<T> GetWaiter<T>(Func<string, T> resultParser, CancellationToken ct);
    Task Send(Message requestMessage);
}