namespace Luna.Channels.Abstractions;

/// <summary>
/// Manages the lifecycle and routing of all registered communication channels.
/// </summary>
public interface IChannelManager
{
    /// <summary>
    /// Registers a channel with this manager.
    /// </summary>
    /// <param name="channel"></param>
    /// <exception cref="InvalidOperationException">Thrown if a channel with the same ID is already registered.</exception>
    void RegisterChannel(IChannel channel);

    /// <summary>
    /// Unregisters a channel by its ID. No-op if the channel is not found.
    /// </summary>
    /// <param name="channelId">The ID of the channel to remove.</param>
    void UnregisterChannel(string channelId);

    /// <summary>
    /// Retrieves a registered channel by its ID.
    /// </summary>
    /// <param name="channelId">The ID of the channel to retrieve.</param>
    /// <returns>The channel, or null if not found.</returns>
    IChannel? GetChannel(string channelId);

    /// <summary>
    /// Returns all currently registered channels.
    /// </summary>
    IReadOnlyList<IChannel> GetAllChannels();

    /// <summary>
    /// Raised after a message has been received and routed.
    /// </summary>
    event EventHandler<ChannelMessageReceivedEventArgs>? MessageRouted;
}