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StopShopping.Services/Implementions/SerialNoGenerator.cs

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+using Microsoft.Extensions.Logging;
+
+namespace StopShopping.Services.Implementions;
+
+public class SerialNoGenerator : ISerialNoGenerator
+{
+    public SerialNoGenerator(ILogger<SerialNoGenerator> logger)
+    {
+        _logger = logger;
+    }
+
+    private readonly ILogger<SerialNoGenerator> _logger;
+
+    private const long START_UTC = 1767196800000; //2026-01-01 00:00:00.000
+    private const int BITS_CALLBACK = 3;
+    private const int BITS_SERIAL = 6;
+    private const long MASK_CALLBACK = ~(-1L << BITS_CALLBACK); //0b_0111
+    private const long MASK_SERIAL = ~(-1L << BITS_SERIAL);
+
+    private readonly object _lockObj = new();
+
+    private long _lastUtc = DateTimeOffset.Now.ToUnixTimeMilliseconds();
+    private long _serial;
+    private long _callbackSerial;
+
+    /// <summary>
+    /// <list type="table">
+    /// <item>
+    /// <term>
+    /// 0000000
+    /// </term>
+    /// <term>
+    /// 00000000000
+    /// </term>
+    /// <term>
+    /// 00000000000
+    /// </term>
+    /// <term>
+    /// 0000000000
+    /// </term>
+    /// </item>
+    /// 
+    /// <item>
+    /// <term>
+    /// 符号位1bit
+    /// </term>
+    /// </item>
+    /// <term>
+    /// 毫秒时间戳56bit
+    /// </term>
+    /// <term>
+    /// 时间回拨标识3bit
+    /// </term>
+    /// <term>
+    /// 毫秒内序号6bit
+    /// </term>
+    /// </list>
+    /// </summary>
+    /// <returns></returns>
+    public string GenerateRequestNo()
+    {
+        lock (_lockObj)
+        {
+            var currUtc = DateTimeOffset.Now.ToUnixTimeMilliseconds();
+
+            if (currUtc < _lastUtc) //时间回拨
+            {
+                currUtc = _lastUtc;
+                _callbackSerial = (_callbackSerial + 1) & MASK_CALLBACK;
+                if (_callbackSerial == 0) //时间回拨标识数据段用完
+                {
+                    _logger.LogWarning("服务器时间不准，序列号可能重复，请检查！");
+                }
+            }
+
+            if (currUtc > _lastUtc)
+            {
+                _serial = 1;
+                _callbackSerial = 0;
+            }
+            else
+            {
+                _serial = (_serial + 1) & MASK_SERIAL;
+                if (_serial == 0) //毫秒内数据段用完
+                {
+                    WaitNextMilliSecond(ref currUtc);
+                    _serial = 1;
+                }
+            }
+
+            _lastUtc = currUtc;
+
+            long serial = ((currUtc - START_UTC) << BITS_CALLBACK + BITS_SERIAL)
+                | (_callbackSerial << BITS_SERIAL)
+                | _serial;
+
+            return string.Format("R{0}", serial);
+        }
+    }
+
+    public string GenerateProductNo()
+    {
+        throw new NotImplementedException();
+    }
+
+    private void WaitNextMilliSecond(ref long curr)
+    {
+        while (_lastUtc >= curr)
+        {
+            curr = DateTimeOffset.Now.ToUnixTimeMilliseconds();
+        }
+    }
+
+    public string GenerateRandomPassword()
+    {
+        throw new NotImplementedException();
+    }
+}