Move some Utils functions to AppDbContext

Elwig/Helpers/AppDbContext.cs

@@ -1,5 +1,7 @@
 using Microsoft.EntityFrameworkCore;
 using Elwig.Models;
+using System.Linq;
+using System.Threading.Tasks;
 
 namespace Elwig.Helpers {
     public class AppDbContext : DbContext {
@@ -27,5 +29,27 @@ namespace Elwig.Helpers {
             optionsBuilder.UseLazyLoadingProxies();
             base.OnConfiguring(optionsBuilder);
         }
+
+        public async Task<bool> MgNrExists(int mgnr) {
+            return await Members.FindAsync(mgnr) != null;
+        }
+
+        public async Task<bool> VNrExists(int vnr) {
+            return await Contracts.FindAsync(vnr) != null;
+        }
+
+        public async Task<int> NextMgNr() {
+            int c = await Members.Select(m => m.MgNr).MinAsync();
+            (await Members.OrderBy(m => m.MgNr).Select(m => m.MgNr).ToListAsync())
+                .ForEach(a => { if (a <= c + 100) c = a; });
+            return c + 1;
+        }
+
+        public async Task<int> NextVNr() {
+            int c = await Contracts.Select(co => co.VNr).MinAsync();
+            (await Contracts.OrderBy(co => co.VNr).Select(co => co.VNr).ToListAsync())
+                .ForEach(a => { if (a <= c + 100) c = a; });
+            return c + 1;
+        }
     }
 }