using Microsoft.Extensions.Logging;
using SilkroadBot.Core.Events;
using SilkroadBot.Core.Networking;
using SilkroadBot.Core.Cryptography;
using SilkroadBot.Domain.Enums;
using SilkroadBot.Domain.Interfaces;
using SilkroadBot.Domain.Models;

namespace SilkroadBot.Core.State;

/// <summary>
/// Central bot state machine. Manages the lifecycle of a single bot instance
/// including connection, authentication, and game session management.
/// </summary>
public class BotContext : IDisposable
{
    private readonly IProtocolAdapter _adapter;
    private readonly IEventDispatcher _eventDispatcher;
    private readonly ILogger<BotContext> _logger;
    private readonly SilkroadSecurity _security;
    private NetworkClient? _networkClient;
    private CancellationTokenSource? _cts;

    public string ProfileId { get; }
    public GameState GameState { get; } = new();
    public ConnectionState ConnectionState { get; private set; } = ConnectionState.Disconnected;
    public ExecutionMode ExecutionMode { get; set; } = ExecutionMode.Clientless;
    public IProtocolAdapter Adapter => _adapter;
    public IEventDispatcher Events => _eventDispatcher;
    
    public event Action<ConnectionState>? StateChanged;

    public BotContext(
        string profileId,
        IProtocolAdapter adapter,
        IEventDispatcher eventDispatcher,
        ILogger<BotContext> logger)
    {
        ProfileId = profileId;
        _adapter = adapter;
        _eventDispatcher = eventDispatcher;
        _logger = logger;
        _security = new SilkroadSecurity();
    }

    /// <summary>
    /// Connect to the gateway server and begin the authentication flow.
    /// </summary>
    public async Task ConnectAsync(string host, int port, CancellationToken ct = default)
    {
        if (ConnectionState != ConnectionState.Disconnected)
            throw new InvalidOperationException($"Cannot connect in state {ConnectionState}");

        _cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
        _networkClient = new NetworkClient(_adapter, 
            LoggerFactory.Create(b => b.AddConsole()).CreateLogger<NetworkClient>());

        _networkClient.PacketReceived += OnPacketReceivedAsync;
        _networkClient.Disconnected += OnDisconnectedAsync;

        SetState(ConnectionState.Connecting);
        
        try
        {
            await _networkClient.ConnectAsync(host, port, _cts.Token);
            SetState(ConnectionState.Handshaking);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to connect to {Host}:{Port}", host, port);
            SetState(ConnectionState.Disconnected);
            throw;
        }
    }

    /// <summary>
    /// Login with credentials.
    /// </summary>
    public async Task LoginAsync(string username, string password, CancellationToken ct = default)
    {
        if (_networkClient == null || !_networkClient.IsConnected)
            throw new InvalidOperationException("Not connected");

        SetState(ConnectionState.Authenticating);

        var writer = new PacketWriter();
        writer.WriteByte(0x01); // Login type
        writer.WriteAscii(username);
        writer.WriteAscii(password);

        var opcode = _adapter.GetOpcodeMap().GetOpcode("LOGIN_REQUEST");
        var packet = Packet.ToServer(opcode, writer.ToArray());
        
        await _networkClient.SendAsync(packet, ct);
        await _eventDispatcher.PublishAsync(new PacketSentEvent { Packet = packet });
    }

    /// <summary>
    /// Send a packet through the connection.
    /// </summary>
    public async Task SendPacketAsync(Packet packet, CancellationToken ct = default)
    {
        if (_networkClient == null || !_networkClient.IsConnected)
            throw new InvalidOperationException("Not connected");

        await _networkClient.SendAsync(packet, ct);
        await _eventDispatcher.PublishAsync(new PacketSentEvent { Packet = packet });
    }

    /// <summary>
    /// Disconnect and cleanup.
    /// </summary>
    public async Task DisconnectAsync()
    {
        if (_networkClient != null)
        {
            await _networkClient.DisconnectAsync();
        }
        SetState(ConnectionState.Disconnected);
    }

    private async Task OnPacketReceivedAsync(Packet packet)
    {
        await _eventDispatcher.PublishAsync(new PacketReceivedEvent { Packet = packet });
        
        // Handle handshake packets
        var opcodeMap = _adapter.GetOpcodeMap();
        var logicalName = opcodeMap.GetLogicalName(packet.Opcode);

        switch (logicalName)
        {
            case "HANDSHAKE":
                await HandleHandshakeAsync(packet);
                break;
            case "LOGIN_RESPONSE":
                HandleLoginResponse(packet);
                break;
            case "HP_MP_UPDATE":
                HandleHealthUpdate(packet);
                break;
            case "CHAT_RECEIVE":
                await HandleChatAsync(packet);
                break;
            case "ENTITY_SPAWN":
                await HandleEntitySpawnAsync(packet);
                break;
            case "ENTITY_DESPAWN":
                await HandleEntityDespawnAsync(packet);
                break;
        }
    }

    private async Task HandleHandshakeAsync(Packet packet)
    {
        _logger.LogDebug("Processing handshake...");
        var response = _security.ProcessHandshake(packet.Payload);
        
        var opcode = _adapter.GetOpcodeMap().GetOpcode("HANDSHAKE_RESPONSE");
        await _networkClient!.SendAsync(Packet.ToServer(opcode, response));
        
        SetState(ConnectionState.Connected);
    }

    private void HandleLoginResponse(Packet packet)
    {
        var reader = new PacketReader(packet.Payload);
        byte result = reader.ReadByte();
        
        if (result == 0x01)
        {
            _logger.LogInformation("Login successful");
            SetState(ConnectionState.InGame);
        }
        else
        {
            _logger.LogWarning("Login failed with code: 0x{Code:X2}", result);
            SetState(ConnectionState.Connected);
        }
    }

    private void HandleHealthUpdate(Packet packet)
    {
        if (packet.Payload.Length < 8) return;
        
        var reader = new PacketReader(packet.Payload);
        int hp = (int)reader.ReadUInt32();
        int mp = (int)reader.ReadUInt32();
        
        GameState.Update(s =>
        {
            s.Character.HP = hp;
            s.Character.MP = mp;
        });

        _ = _eventDispatcher.PublishAsync(new HealthChangedEvent
        {
            HP = hp,
            MaxHP = GameState.Character.MaxHP,
            MP = mp,
            MaxMP = GameState.Character.MaxMP
        });
    }

    private async Task HandleChatAsync(Packet packet)
    {
        var reader = new PacketReader(packet.Payload);
        var chatType = (ChatType)reader.ReadByte();
        var sender = reader.ReadAscii();
        var message = reader.ReadUnicode();

        await _eventDispatcher.PublishAsync(new ChatMessageEvent
        {
            ChatType = chatType,
            Sender = sender,
            Message = message
        });
    }

    private async Task HandleEntitySpawnAsync(Packet packet)
    {
        var reader = new PacketReader(packet.Payload);
        var entity = new GameEntity
        {
            UniqueId = reader.ReadUInt32(),
            ModelId = reader.ReadUInt32()
        };

        GameState.Update(s => s.NearbyEntities.Add(entity));
        await _eventDispatcher.PublishAsync(new EntitySpawnEvent { Entity = entity });
    }

    private async Task HandleEntityDespawnAsync(Packet packet)
    {
        var reader = new PacketReader(packet.Payload);
        uint uid = reader.ReadUInt32();

        GameState.Update(s => s.NearbyEntities.RemoveAll(e => e.UniqueId == uid));
        await _eventDispatcher.PublishAsync(new EntityDespawnEvent { UniqueId = uid });
    }

    private Task OnDisconnectedAsync(Exception? ex)
    {
        if (ex != null)
            _logger.LogError(ex, "Disconnected with error");
        else
            _logger.LogInformation("Disconnected");
        
        SetState(ConnectionState.Disconnected);
        return Task.CompletedTask;
    }

    private void SetState(ConnectionState newState)
    {
        var oldState = ConnectionState;
        ConnectionState = newState;
        GameState.ConnectionState = newState;
        StateChanged?.Invoke(newState);
        
        _ = _eventDispatcher.PublishAsync(new ConnectionStateChangedEvent 
        { 
            OldState = oldState, 
            NewState = newState 
        });
    }

    public void Dispose()
    {
        _cts?.Cancel();
        _cts?.Dispose();
        _networkClient?.Dispose();
    }
}