using System.Collections.Immutable;
using Luna.Channels.Abstractions;
using Luna.Core.Abstractions;
using Microsoft.Extensions.Logging;

namespace Luna.Channels;

public class ChannelManager(ISessionManager sessionManager, ILogger<ChannelManager> logger) : IChannelManager
{
    private readonly Dictionary<string, IChannel> channels = new();
    private readonly Dictionary<string, string> sessionMap = new();
    
    public event EventHandler<ChannelMessageReceivedEventArgs>? MessageRouted;
    
    public void RegisterChannel(IChannel channel)
    {
        if (!channels.TryAdd(channel.ChannelId, channel))
            throw new InvalidOperationException($"Channel with id {channel.ChannelId} is already registered.");

        channel.MessageReceived += OnMessageReceivedAsync;
    }

    public void UnregisterChannel(string channelId)
    {
        if (!channels.TryGetValue(channelId, out var channel))
            return;

        channel.MessageReceived -= OnMessageReceivedAsync;
        channels.Remove(channelId);
    }

    public IChannel? GetChannel(string channelId)
    {
        channels.TryGetValue(channelId, out var channel);
        return channel;
    }

    public IReadOnlyList<IChannel> GetAllChannels()
        => channels.Values.ToImmutableList();

    private async Task OnMessageReceivedAsync(object? sender, ChannelMessageReceivedEventArgs args)
    {
        if (args.IsHandled)
            return;
        
        var channel = args.Channel;
        var message = args.Message;
        
        try
        {
            var response = sessionManager
                .RouteMessagesAsync(message.Content, message.ConversationId, channel.ChannelId);
            
            await channel.SendStreamingMessageAsync(response);
            MessageRouted?.Invoke(this, args);
        }
        catch (Exception exception)
        {
            logger.LogError(exception, "Message routing for channel of type {Type} with id {Id} failed", channel.ChannelType, channel.ChannelId);
        }
    }
}