Allow to add and remove sound synthesizers from machine details in admin view.

Marechai/Services/SoundSynthsByMachineService.cs

@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Marechai.Database.Models;
+using Marechai.ViewModels;
+using Microsoft.EntityFrameworkCore;
+
+namespace Marechai.Services
+{
+    public class SoundSynthsByMachineService
+    {
+        readonly MarechaiContext _context;
+
+        public SoundSynthsByMachineService(MarechaiContext context) => _context = context;
+
+        public async Task<List<SoundSynthByMachineViewModel>> GetByMachine(int machineId) =>
+            await _context.SoundByMachine.Where(g => g.MachineId == machineId).
+                           Select(g => new SoundSynthByMachineViewModel
+                           {
+                               Id           = g.Id, Name = g.SoundSynth.Name, CompanyName = g.SoundSynth.Company.Name,
+                               SoundSynthId = g.SoundSynthId, MachineId = g.MachineId
+                           }).OrderBy(g => g.CompanyName).ThenBy(g => g.Name).ToListAsync();
+
+        public async Task DeleteAsync(long id)
+        {
+            SoundByMachine item = await _context.SoundByMachine.FindAsync(id);
+
+            if(item is null)
+                return;
+
+            _context.SoundByMachine.Remove(item);
+
+            await _context.SaveChangesAsync();
+        }
+
+        public async Task<long> CreateAsync(int soundSynthId, int machineId)
+        {
+            var item = new SoundByMachine
+            {
+                SoundSynthId = soundSynthId, MachineId = machineId
+            };
+
+            await _context.SoundByMachine.AddAsync(item);
+            await _context.SaveChangesAsync();
+
+            return item.Id;
+        }
+    }
+}