implement `UpdateBestBuddy`

src/Controllers/Common/ContentController.cs

@@ -1187,6 +1187,20 @@ public class ContentController : Controller {
         else return Ok(false);
     }
 
+    [HttpPost]
+    [Produces("application/xml")]
+    [Route("ContentWebService.asmx/UpdateBestBuddy")]
+    [VikingSession]
+    public IActionResult SetBestBuddy(Viking viking, [FromForm] Guid buddyUserID, [FromForm] bool bestBuddy)
+    {
+        // get buddy
+        Viking? buddyViking = ctx.Vikings.FirstOrDefault(e => e.Uid == buddyUserID);
+
+        if (buddyViking != null)
+            return Ok(buddyService.UpdateBestBuddy(viking, buddyViking, bestBuddy));
+        else return Ok(false);
+    }
+
     [HttpPost]
     [Produces("application/xml")]
     [Route("ContentWebService.asmx/GetBuddyList")]

src/Services/BuddyService.cs

@@ -77,6 +77,22 @@ public class BuddyService
         } else return false;
     }
 
+    public bool UpdateBestBuddy(Viking viking, Viking buddyViking, bool bestBuddy)
+    {
+        // find relation
+        Model.Buddy? buddy = ctx.Buddies.Where(e => e.VikingId == viking.Id || e.BuddyVikingId == viking.Id)
+            .FirstOrDefault(e => e.BuddyVikingId == buddyViking.Id || e.VikingId == buddyViking.Id);
+
+        if (buddy != null)
+        {
+            if (buddy.VikingId == viking.Id)
+                buddy.IsBestFriend1 = bestBuddy;
+            else buddy.IsBestFriend2 = bestBuddy;
+
+            return true;
+        } else return false;
+    }
+
     public bool RemoveBuddy(Viking viking, Viking buddyViking)
     {
         // find relation