using System.Threading.Channels;

namespace Admin.NET.Core.Ai.Services.SSE;

/// <summary>
/// SSE通道管理
/// </summary>
public class SseChannelManager: ISingleton
{
    private readonly ConcurrentDictionary<long, Channel<string>> _userChannels = new();

    /// <summary>
    /// 注册
    /// </summary>
    /// <param name="userId"></param>
    /// <returns></returns>
    public ChannelReader<string> Register(long userId)
    {
        var channel = Channel.CreateBounded<string>(new BoundedChannelOptions(100){
            FullMode = BoundedChannelFullMode.Wait
        });
        _userChannels[userId] = channel;
        return channel.Reader;
    }

    /// <summary>
    /// 注销
    /// </summary>
    /// <param name="userId"></param>
    public void Unregister(long userId)
    {
        if (_userChannels.TryRemove(userId, out var channel))
        {
            channel.Writer.TryComplete(); // 结束读端
        }
    }

    /// <summary>
    /// 发送消息
    /// </summary>
    /// <param name="userId"></param>
    /// <param name="message"></param>
    /// <param name="cancellationToken"></param>
    public async Task SendMessageAsync(long userId, string message, CancellationToken cancellationToken = default)
    {
        if (_userChannels.TryGetValue(userId, out var channel))
        {
            await channel.Writer.WriteAsync(message,cancellationToken);
        }
    }
}