BilllingVariant: Allow for credits with negative value

Elwig/Helpers/Billing/BillingVariant.cs

@@ -98,7 +98,7 @@ namespace Elwig.Helpers.Billing {
                         LEFT JOIN v_penalty_area_commitments u ON (u.year, u.mgnr) = (s.year, m.mgnr)
                         LEFT JOIN v_auto_business_shares a ON (a.year, a.mgnr) = (s.year, m.mgnr)
                         LEFT JOIN payment_custom x ON (x.year, x.mgnr) = (s.year, m.mgnr)
-                    WHERE s.year = {Year} AND v.avnr = {AvNr} AND p.amount > COALESCE(lp.amount, 0);
+                    WHERE s.year = {Year} AND v.avnr = {AvNr} AND p.amount != COALESCE(lp.amount, 0);
                     """);
             await cnx.ExecuteBatch($"""
                 UPDATE payment_variant SET test_variant = FALSE WHERE (year, avnr) = ({Year}, {AvNr});

Elwig/Services/PaymentVariantService.cs

@@ -8,6 +8,7 @@ using Elwig.ViewModels;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Win32;
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
 using System.Threading.Tasks;
@@ -142,7 +143,7 @@ namespace Elwig.Services {
             });
 
             var credits = ctx.Credits.Where(c => c.Year == v.Year && c.AvNr == v.AvNr);
-            if (!credits.Any()) {
+            if (!(await credits.AnyAsync())) {
                 long lastTotalSum = 0;
                 decimal vatSum = 0;
                 var currentPayments = await ctx.MemberPayments
@@ -150,8 +151,7 @@ namespace Elwig.Services {
                         .ToDictionaryAsync(p => p.MgNr);
                 var lastV = await ctx.PaymentVariants
                     .Where(l => l.Year == v.Year && !l.TestVariant)
-                    .OrderByDescending(l => l.TransferDateString ?? l.DateString)
+                    .OrderByDescending(l => l.TransferDateString ?? l.DateString).ThenByDescending(l => l.AvNr)
-                    .ThenByDescending(l => l.AvNr)
                     .FirstOrDefaultAsync();
                 if (lastV != null) {
                     var lastPayments = await ctx.MemberPayments
@@ -160,8 +160,8 @@ namespace Elwig.Services {
                     lastTotalSum = lastPayments.Sum(e => e.Value.AmountValue);
                     foreach (int mgnr in currentPayments.Keys) {
                         var c = currentPayments[mgnr];
-                        var l = lastPayments[mgnr];
+                        var l = lastPayments.GetValueOrDefault(mgnr);
-                        vatSum += (c.Amount - l.Amount) * (decimal)(c.Member.IsBuchführend ? v.Season.VatNormal : v.Season.VatFlatrate);
+                        vatSum += (c.Amount - (l?.Amount ?? 0)) * (decimal)(c.Member.IsBuchführend ? v.Season.VatNormal : v.Season.VatFlatrate);
                     }
                 } else {
                     vatSum = currentPayments.Sum(e => e.Value.Amount * (decimal)(e.Value.Member.IsBuchführend ? v.Season.VatNormal : v.Season.VatFlatrate));
@@ -369,10 +369,42 @@ namespace Elwig.Services {
         }
 
         public static async Task Commit(int year, int avnr) {
+            List<Member> membersLess = [];
+            using (var ctx = new AppDbContext()) {
+                var lastAvNr = await ctx.PaymentVariants
+                    .Where(v => v.Year == year && !v.TestVariant)
+                    .OrderByDescending(v => v.TransferDateString ?? v.DateString).ThenByDescending(v => v.AvNr)
+                    .Select(v => v.AvNr)
+                    .FirstOrDefaultAsync();
+                if (lastAvNr != 0) {
+                    var cur = await ctx.MemberPayments.Include(p => p.Member).Where(p => p.Year == year && p.AvNr == avnr).ToDictionaryAsync(p => p.Member.MgNr, p => p);
+                    var last = await ctx.MemberPayments.Include(p => p.Member).Where(p => p.Year == year && p.AvNr == lastAvNr).ToDictionaryAsync(p => p.Member.MgNr, p => p);
+                    membersLess = [.. last.Where(p => (cur.TryGetValue(p.Key, out var c) ? c.Amount : 0) < p.Value.Amount).Select(p => p.Value.Member)];
+                }
+            }
+            if (membersLess.Count > 0) {
+                var res = MessageBox.Show($"Achtung: Bei {membersLess.Count:N0} Mitglied(ern) ist der Soll-Betrag der Auszahlung (\"Gesamtbetrag\") kleiner als bei der letzten Auszahlung. Das sollte nicht vorkommen!\n\n" +
+                    $"{string.Join(", ", membersLess.Select(m => $"{m.AdministrativeName} ({m.MgNr})"))}\n\n" +
+                    "Soll trotzdem forgefahren werden?",
+                    "Kleinerer Gesamtbetrag", MessageBoxButton.OKCancel, MessageBoxImage.Warning, MessageBoxResult.Cancel);
+                if (res != MessageBoxResult.OK)
+                    return;
+            }
+
             await Task.Run(async () => {
                 var b = await BillingVariant.Create(year, avnr);
                 await b.Commit();
             });
+
+            List<Member> membersNeg = [];
+            using (var ctx = new AppDbContext()) {
+                membersNeg = await ctx.Credits.Where(c => c.Year == year && c.AvNr == avnr && c.AmountValue < 0).Select(c => c.Member).ToListAsync();
+            }
+            if (membersNeg.Count > 0) {
+                var res = MessageBox.Show($"Achtung: Bei {membersNeg.Count:N0} Mitglied(ern) ist der Auszahlungsbetrag negativ!\n\n" +
+                    $"{string.Join(", ", membersNeg.Select(m => $"{m.AdministrativeName} ({m.MgNr})"))}",
+                    "Negativer Auszahlungsbetrag", MessageBoxButton.OK, MessageBoxImage.Warning);
+            }
         }
 
         public static async Task Revert(int year, int avnr) {