using System.Collections.Generic;
using System.Linq;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace WIDESEAWCS_Tasks.SocketServer
{
    public partial class TcpSocketServer
    {
        /// <summary>
        /// ¼ìË÷µ±Ç°ÔÚ·þÎñÖÐ×¢²áµÄËùÓпͻ§¶Ë±êʶ·ûµÄÖ»¶ÁÁÐ±í¡£
        /// </summary>
        /// <remarks>·µ»ØµÄÁбí±íʾµ÷ÓÃʱ¿Ì¿Í»§¶ËIDµÄ¿ìÕÕ¡£ºóÐø¶Ô¿Í»§¶Ë¼¯ºÏµÄ¸ü¸Ä²»»áÓ°Ïì·µ»ØµÄÁÐ±í¡£´Ë·½·¨ÊÇḬ̈߳²È«µÄ¡£</remarks>
        /// <returns>°üº¬¿Í»§¶ËIDµÄ<see cref="IReadOnlyList{String}"/>¡£Èç¹ûûÓпͻ§¶Ë×¢²á£¬ÁÐ±í½«Îª¿Õ¡£</returns>
        public IReadOnlyList<string> GetClientIds()
        {
            lock (_syncRoot)
            {
                return _clients.Keys.ToList();
            }
        }

        /// <summary>
        /// ¼ìË÷ÓëÖ¸¶¨É豸±êʶ·û¹ØÁªµÄ¿Í»§¶Ë±êʶ·û¡£
        /// </summary>
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        /// <param name="deviceId">Òª¼ìË÷¿Í»§¶Ë±êʶ·ûµÄÉ豸µÄΨһ±êʶ·û¡£²»ÄÜΪnull¡£</param>
        /// <returns>ÓëÖ¸¶¨É豸±êʶ·û¹ØÁªµÄ¿Í»§¶Ë±êʶ·û£¬Èç¹û²»´æÔÚ¹ØÁªÔò·µ»Ønull¡£</returns>
        public string? GetClientIdByDevice(string deviceId)
        {
            lock (_syncRoot)
            {
                return _deviceBindings.TryGetValue(deviceId, out var cid) ? cid : null;
            }
        }

        /// <summary>
        /// Òì²½ÏòÖ¸¶¨É豸·¢ËÍÏûÏ¢¡£
        /// </summary>
        /// <remarks>Èç¹ûÖ¸¶¨É豸δע²á»òÎÞ·¨ÕÒµ½£¬Ôò·µ»Ø <see langword="false"/>¡£</remarks>
        /// <param name="deviceId">Ä¿±êÉ豸µÄΨһ±êʶ·û¡£²»ÄÜΪnull»ò¿Õ¡£</param>
        /// <param name="message">Òª·¢Ë͸øÉ豸µÄÏûÏ¢¡£²»ÄÜΪnull¡£</param>
        /// <returns>±íʾÒì²½²Ù×÷µÄÈÎÎñ¡£Èç¹ûÏûÏ¢³É¹¦·¢ËÍ£¬ÈÎÎñ½á¹ûΪ <see langword="true"/>£»
        /// ·ñÔòΪ <see langword="false"/>¡£</returns>
        public Task<bool> SendToDeviceAsync(string deviceId, string message)
        {
            var clientId = GetClientIdByDevice(deviceId);
            if (clientId == null) return Task.FromResult(false);
            return SendToClientAsync(clientId, message);
        }

        /// <summary>
        /// ͨ¹ýTCPÁ¬½ÓÒì²½ÏòÖ¸¶¨¿Í»§¶Ë·¢ËÍ´øÖ¡µÄÎı¾ÏûÏ¢¡£
        /// </summary>
        /// <remarks>Èç¹û¿Í»§¶ËδÁ¬½Ó»ò²»´æÔÚ£¬´Ë·½·¨½«·µ»Ø <see langword="false"/> ÇÒ²»·¢ËÍÏûÏ¢¡£
        /// ÏûÏ¢½«ÓÅÏÈʹÓÿͻ§¶ËÊ×Ñ¡µÄÎı¾±àÂë½øÐбàÂ룻·ñÔòʹÓÃĬÈϱàÂë¡£
        /// ´Ë·½·¨¶ÔÓÚÏò²»Í¬¿Í»§¶ËµÄ²¢·¢µ÷ÓÃÊÇḬ̈߳²È«µÄ¡£</remarks>
        /// <param name="clientId">Òª·¢ËÍÏûÏ¢µ½µÄ¿Í»§¶ËµÄΨһ±êʶ·û¡£±ØÐë¶ÔÓ¦ÒÑÁ¬½ÓµÄ¿Í»§¶Ë¡£</param>
        /// <param name="message">Òª·¢Ë͸ø¿Í»§¶ËµÄÎı¾ÏûÏ¢¡£²»ÄÜΪnull¡£</param>
        /// <returns>±íʾÒì²½²Ù×÷µÄÈÎÎñ¡£Èç¹ûÏûÏ¢³É¹¦·¢ËÍ£¬ÈÎÎñ½á¹ûΪ <see langword="true"/>£»
        /// ·ñÔò£¬Èç¹û¿Í»§¶ËδÁ¬½Ó»ò²»´æÔÚ£¬½á¹ûΪ <see langword="false"/>¡£</returns>
        public async Task<bool> SendToClientAsync(string clientId, string message)
        {
            TcpClient? client;
            SemaphoreSlim? sem = null;
            Encoding? enc = null;
            lock (_syncRoot)
            {
                _clients.TryGetValue(clientId, out client);
                _clientLocks.TryGetValue(clientId, out sem);
                _clientEncodings.TryGetValue(clientId, out enc);
            }

            if (client == null || !client.Connected)
            {
                return false;
            }

            enc ??= _textEncoding;

            if (sem != null) await sem.WaitAsync();
            try
            {
                var ns = client.GetStream();
                var framedMessage = BuildFramedMessage(message);
                var data = enc.GetBytes(framedMessage);
                await ns.WriteAsync(data, 0, data.Length);
            }
            finally
            {
                if (sem != null) sem.Release();
            }
            return true;
        }

        /// <summary>
        /// Òì²½ÏòËùÓÐÒÑÁ¬½ÓµÄ¿Í»§¶Ë·¢ËÍÖ¸¶¨µÄÏûÏ¢¡£
        /// </summary>
        /// <remarks>Èç¹ûÏòij¸ö¿Í»§¶Ë·¢ËÍÏûϢʱ·¢Éú´íÎó£¬Òì³£½«±»ÒÖÖƲ¢¼ÌÐøÏòÆäËû¿Í»§¶Ë¹ã²¥¡£
        /// µ±ËùÓз¢ËͲÙ×÷Íê³Éºó£¬´Ë·½·¨½áÊø¡£</remarks>
        /// <param name="message">Òª¹ã²¥¸øËùÓпͻ§¶ËµÄÏûÏ¢¡£²»ÄÜΪnull¡£</param>
        /// <returns>±íʾÒì²½¹ã²¥²Ù×÷µÄÈÎÎñ¡£</returns>
        public async Task BroadcastAsync(string message)
        {
            List<TcpClient> clients;
            lock (_syncRoot)
            {
                clients = _clients.Values.ToList();
            }

            await Task.WhenAll(clients.Select(c => Task.Run(async () =>
            {
                try { await SendMessageAsync(c, message); } catch { }
            })));
        }

        /// <summary>
        /// ͨ¹ýÍøÂçÁ÷Òì²½ÏòÖ¸¶¨µÄTCP¿Í»§¶Ë·¢ËÍ´øÖ¡µÄÎı¾ÏûÏ¢¡£
        /// </summary>
        /// <remarks>Èç¹û¿Í»§¶ËΪnull»òδÁ¬½Ó£¬´Ë·½·¨½«Á¢¼´·µ»Ø¶ø²»·¢ËÍÏûÏ¢¡£
        /// ÏûÏ¢½«Ê¹ÓÃÅäÖõÄÎı¾±àÂë½øÐбàÂë²¢Ìí¼ÓÖ¡Í·ºóͨ¹ýÍøÂçÁ÷·¢ËÍ¡£</remarks>
        /// <param name="client">Òª·¢ËÍÏûÏ¢µ½µÄTCP¿Í»§¶Ë¡£±ØÐë´¦ÓÚÁ¬½Ó״̬£»·ñÔò·½·¨²»Ö´ÐÐÈκβÙ×÷¡£</param>
        /// <param name="message">Òª·¢Ë͸ø¿Í»§¶ËµÄÎı¾ÏûÏ¢¡£ÏûÏ¢ÔÚ´«ÊäÇ°½«±»±àÂë²¢Ìí¼ÓÖ¡Í·¡£</param>
        /// <returns>±íʾÒì²½·¢ËͲÙ×÷µÄÈÎÎñ¡£</returns>
        private async Task SendMessageAsync(TcpClient client, string message)
        {
            if (client == null || !client.Connected)
            {
                return;
            }

            NetworkStream stream = client.GetStream();
            var framedMessage = BuildFramedMessage(message);
            var data = _textEncoding.GetBytes(framedMessage);
            await stream.WriteAsync(data, 0, data.Length);
        }
    }
}