Feature: Google oauth

src/Infrastructure/Services/UserService.cs

@@ -32,7 +32,7 @@ public class UserService(UserManager<ApplicationUser> userManager) : IUserServic
 
     public async Task CreateUserAsync(Userinfo userInfo)
     {
-        await CreateUserAsync(userInfo.Email, userInfo.GivenName, userInfo.GivenName, userInfo.FamilyName, GeneratePassword(24));
+        await CreateUserAsync(userInfo.Email, userInfo.GivenName, userInfo.GivenName, userInfo.FamilyName, RandomGenerator.RandomString(24));
     }
 
     public async Task<UserModel?> FindUserByIdAsync(string id)
@@ -82,23 +82,55 @@ public class UserService(UserManager<ApplicationUser> userManager) : IUserServic
 
         return userModel;
     }
-    
-    private const string Characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
-    private const string SpecialCharacters = "!@#$%^&*()_+";
-    
-    private String GeneratePassword(int length)
-    {
-        // Using a string builder has additional overhead, maybe we can find something else
-        var password = new StringBuilder();
-        
-        for (var i = 0; i < length; i++)
-        {
-            password.Append(Characters[_random.Next(Characters.Length)]);
-        }
-        
-        password.Append(SpecialCharacters[_random.Next(SpecialCharacters.Length)]);
-        
-        return password.ToString();
-    }
 }
 
+public class RandomGenerator
+{
+    private const string LetterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                                       + "0123456789"
+                                       + "!@#$%^&*()_+"
+                                       + "-=[];',./`~{}|:\"<>?";
+    private const int LetterIdxBits = 6;
+    private const int LetterIdxMask = 1 << LetterIdxBits;
+    private const int LetterIdxMax = 64 / LetterIdxBits;
+
+    private static readonly Random Src = new();
+
+    public static byte[] RandBytesMaskSrc(int n)
+    {
+        var b = new byte[n];
+
+        for (var i = n - 1; i >= 0;)
+        {
+            long cache = Src.NextInt64();
+            int remain = LetterIdxMax;
+
+            while (remain != 0)
+            {
+                if (i < 0)
+                    break;
+
+                if (cache == 0)
+                    cache = Src.NextInt64();
+
+                var idx = (int)(cache & LetterIdxMask);
+                if (idx < LetterBytes.Length)
+                {
+                    b[i] = (byte)LetterBytes[idx];
+                    i--;
+                }
+
+                cache >>= LetterIdxBits;
+                remain--;
+            }
+        }
+
+        return b;
+    }
+    
+    public static string RandomString(int length)
+    {
+        var bytes = RandBytesMaskSrc(length);
+        return Encoding.UTF8.GetString(bytes); // Equivalent for *(string*)(&bytes[0])
+    }
+}