using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.SignalR.Client;
using RobotNet.VDA5050.State;
using RobotNet10.FleetManager.Shared.DTOs.Robot;

namespace RobotNet10.FleetManager.Client.Services;

/// <summary>
/// SignalR Hub Client for robot state and visualization updates.
/// Manages connection to the SignalR hub and provides methods to subscribe/unsubscribe to robot updates.
/// </summary>
/// <remarks>
/// This client automatically handles reconnection and provides events for state and visualization updates.
/// Dispose the client when done to properly clean up the connection.
/// </remarks>
public class RobotStateHubClient : IAsyncDisposable
{
    private readonly HubConnection _hubConnection;
    private readonly ILogger<RobotStateHubClient>? _logger;

    public event Action<RobotMonitorBoardcastData>? OnMonitorBoardcastUpdate;
    public event Action<StateMsg>? OnStateUpdate;
    public event Action<string>? OnConnectionError;
    public event Action? OnMonitorDeactivated;

    public RobotStateHubClient(NavigationManager navigationManager, ILogger<RobotStateHubClient>? logger = null)
    {
        _logger = logger;
        var hubUrl = navigationManager.ToAbsoluteUri("/hubs/robot-state");
        
        _hubConnection = new HubConnectionBuilder()
            .WithUrl(hubUrl)
            .WithAutomaticReconnect()
            .Build();

        // Register event handlers
        _hubConnection.On<StateMsg>("OnStateUpdate", (state) =>
        {
            OnStateUpdate?.Invoke(state);
        });

        _hubConnection.On<RobotMonitorBoardcastData>("OnMonitorUpdate", (state) =>
        {
            OnMonitorBoardcastUpdate?.Invoke(state);
        });

        _hubConnection.On("OnMonitorDeactivated", () =>
        {
            OnMonitorDeactivated?.Invoke();
        });

        _hubConnection.Closed += async (error) =>
        {
            if (error != null)
            {
                _logger?.LogError(error, "SignalR connection closed with error");
                OnConnectionError?.Invoke(error.Message);
            }
            else
            {
                _logger?.LogInformation("SignalR connection closed");
            }
            await Task.CompletedTask;
        };

        _hubConnection.Reconnecting += async (error) =>
        {
            _logger?.LogWarning(error, "SignalR connection reconnecting");
            await Task.CompletedTask;
        };

        _hubConnection.Reconnected += async (connectionId) =>
        {
            _logger?.LogInformation("SignalR connection reconnected with ID {ConnectionId}", connectionId);
            await Task.CompletedTask;
        };
    }

    /// <summary>
    /// Connect to the SignalR hub
    /// </summary>
    public async Task ConnectAsync()
    {
        try
        {
            if (_hubConnection.State == HubConnectionState.Disconnected)
            {
                await _hubConnection.StartAsync();
                _logger?.LogInformation("SignalR hub connected");
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error connecting to SignalR hub");
            OnConnectionError?.Invoke(ex.Message);
            throw;
        }
    }

    /// <summary>
    /// Disconnect from the SignalR hub
    /// </summary>
    public async Task DisconnectAsync()
    {
        try
        {
            if (_hubConnection.State != HubConnectionState.Disconnected)
            {
                await _hubConnection.StopAsync();
                _logger?.LogInformation("SignalR hub disconnected");
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error disconnecting from SignalR hub");
            throw;
        }
    }

    /// <summary>
    /// Subscribe to receive updates for a specific robot
    /// </summary>
    /// <param name="robotId">Robot identifier (serialNumber)</param>
    public async Task SubscribeToRobotAsync(string robotId)
    {
        try
        {
            if (_hubConnection.State == HubConnectionState.Connected)
            {
                await _hubConnection.InvokeAsync("SubscribeToRobot", robotId);
                _logger?.LogInformation("Subscribed to robot {RobotId}", robotId);
            }
            else
            {
                _logger?.LogWarning("Cannot subscribe to robot {RobotId}: Hub not connected", robotId);
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error subscribing to robot {RobotId}", robotId);
            throw;
        }
    }

    /// <summary>
    /// Unsubscribe from updates for a specific robot
    /// </summary>
    /// <param name="robotId">Robot identifier (serialNumber)</param>
    public async Task UnsubscribeFromRobotAsync(string robotId)
    {
        try
        {
            if (_hubConnection.State == HubConnectionState.Connected)
            {
                await _hubConnection.InvokeAsync("UnsubscribeFromRobot", robotId);
                _logger?.LogInformation("Unsubscribed from robot {RobotId}", robotId);
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error unsubscribing from robot {RobotId}", robotId);
            throw;
        }
    }

    /// <summary>
    /// Subscribe to receive monitor updates for a specific levelId
    /// Each connection can only subscribe to one levelId at a time.
    /// Maximum 5 connections per levelId (FIFO).
    /// </summary>
    /// <param name="levelId">Level identifier (LayoutLevel.Id)</param>
    public async Task SubscribeToLevelForMonitorAsync(Guid levelId)
    {
        try
        {
            if (_hubConnection.State == HubConnectionState.Connected)
            {
                await _hubConnection.InvokeAsync("SubscribeToLevelForMonitor", levelId);
                _logger?.LogInformation("Subscribed to level {LevelId} for monitor", levelId);
            }
            else
            {
                _logger?.LogWarning("Cannot subscribe to level {LevelId}: Hub not connected", levelId);
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error subscribing to level {LevelId} for monitor", levelId);
            throw;
        }
    }

    /// <summary>
    /// Unsubscribe from monitor updates for the current level
    /// </summary>
    public async Task UnsubscribeFromLevelForMonitorAsync()
    {
        try
        {
            if (_hubConnection.State == HubConnectionState.Connected)
            {
                await _hubConnection.InvokeAsync("UnsubscribeFromLevelForMonitor");
                _logger?.LogInformation("Unsubscribed from level for monitor");
            }
        }
        catch (Exception ex)
        {
            _logger?.LogError(ex, "Error unsubscribing from level for monitor");
            throw;
        }
    }

    /// <summary>
    /// Get the current connection state
    /// </summary>
    public HubConnectionState ConnectionState => _hubConnection.State;

    public async ValueTask DisposeAsync()
    {
        if (_hubConnection != null)
        {
            await DisconnectAsync();
            await _hubConnection.DisposeAsync();
        }
        GC.SuppressFinalize(this);
    }
}