Return proper responses for missing seed ids

ALttPRandomizer/Service/RandomizeService.cs

@@ -1,5 +1,6 @@
 using ALttPRandomizer.Model;
 using Microsoft.Extensions.Logging;
+using System.Threading.Tasks;
 
 namespace ALttPRandomizer.Service {
     public class RandomizeService {
@@ -14,10 +15,10 @@ namespace ALttPRandomizer.Service {
         private IdGenerator IdGenerator { get; }
         private Randomizer Randomizer { get; }
 
-        public string RandomizeSeed(SeedSettings settings) {
+        public async Task<string> RandomizeSeed(SeedSettings settings) {
             var id = this.IdGenerator.GenerateId();
             this.Logger.LogInformation("Generating seed {seedId} with settings {@settings}", id, settings);
-            this.Randomizer.Randomize(id, settings);
+            await this.Randomizer.Randomize(id, settings);
             return id;
         }
     }

ALttPRandomizer/Service/SeedService.cs

@@ -1,21 +1,26 @@
 namespace ALttPRandomizer.Service {
     using ALttPRandomizer.Azure;
     using ALttPRandomizer.Model;
+    using Microsoft.Extensions.Logging;
     using System;
     using System.Collections.Generic;
     using System.Text.Json;
     using System.Threading.Tasks;
 
     public class SeedService {
-        public SeedService(AzureStorage azureStorage) {
+        public SeedService(AzureStorage azureStorage, ILogger<SeedService> logger) {
             this.AzureStorage = azureStorage;
+            this.Logger = logger;
         }
 
         private AzureStorage AzureStorage { get; }
+        private ILogger<SeedService> Logger { get; }
 
         public async Task<IDictionary<string, object>> GetSeed(string seedId) {
             var files = await this.AzureStorage.GetFiles(seedId);
 
+            this.Logger.LogDebug("Found files: {@files}", files.Keys);
+
             var result = new Dictionary<string, object>();
 
             if (!files.TryGetValue("settings.json", out var settingsData)) {