using Luna.Shared;

namespace Luna.Channels.Abstractions;

public delegate Task ChannelMessageReceivedEventHandler(object? sender, ChannelMessageReceivedEventArgs args);
public delegate Task ChannelConnectionChangedEventHandler(object? sender, ChannelConnectionEventArgs args);

/// <summary>
/// Represents a communication channel for the Luna AI Assistant.
/// Channels handle sending and receiving messages via different platforms
/// (e.g., CLI, Telegram, Discord, Email).
/// </summary>
public interface IChannel : IDisposable
{
    /// <summary>
    /// Unique identifier for this channel instance
    /// </summary>
    string ChannelId { get; }

    /// <summary>
    /// Type of channel (e.g., "cli", "telegram", "discord")
    /// </summary>
    string ChannelType { get; }

    /// <summary>
    /// Display name for the channel
    /// </summary>
    string DisplayName { get; }

    /// <summary>
    /// Indicates whether the channel is currently connected and ready
    /// </summary>
    bool IsConnected { get; }

    /// <summary>
    /// Event raised when a message is received from the channel
    /// </summary>
    event ChannelMessageReceivedEventHandler? MessageReceived;

    /// <summary>
    /// Event raised when the channel connection state changes
    /// </summary>
    event ChannelConnectionChangedEventHandler? ConnectionStateChanged;

    Task<bool> VerifyChannelLinkAsync();
    
    /// <summary>
    /// Send a message to the channel
    /// </summary>
    /// <param name="message">The message to send</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Task representing the send operation</returns>
    Task SendMessageAsync(ChannelMessage message, CancellationToken cancellationToken = default);

    /// <summary>
    /// Send a streaming response to the channel
    /// </summary>
    /// <param name="messageStream">Async enumerable of response updates</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>Task representing the send operation</returns>
    Task SendStreamingMessageAsync(IAsyncEnumerable<ChatStreamUpdate> messageStream, CancellationToken cancellationToken = default);
}