Add seed-fetching service

ALttPRandomizer/Azure/AzureStorage.cs

@@ -0,0 +1,57 @@
+namespace ALttPRandomizer.Azure {
+    using global::Azure.Storage.Blobs;
+    using Microsoft.Extensions.Logging;
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Threading.Tasks;
+
+    public class AzureStorage {
+        public AzureStorage(BlobContainerClient blobClient, ILogger<AzureStorage> logger) {
+            this.BlobClient = blobClient;
+            this.Logger = logger;
+        }
+
+        private ILogger<AzureStorage> Logger { get; }
+        private BlobContainerClient BlobClient { get; }
+
+        public async Task UploadFile(string name, Stream data) {
+            await BlobClient.UploadBlobAsync(name, data);
+        }
+
+        public async Task UploadFileAndDelete(string name, string filepath) {
+            using (var stream = new FileStream(filepath, FileMode.Open, FileAccess.Read)) {
+                this.Logger.LogDebug("Uploading file {filepath} -> {name}", filepath, name);
+                await this.UploadFile(name, stream);
+            }
+
+            this.Logger.LogDebug("Deleting file {filepath}", filepath);
+            File.Delete(filepath);
+        }
+
+        public async Task<Dictionary<string, BinaryData>> GetFiles(string seedId) {
+            var prefix = seedId + "/";
+            var blobs = this.BlobClient.GetBlobsAsync(prefix: prefix);
+
+            var data = new Dictionary<string, BinaryData>();
+
+            await foreach (var blob in blobs) {
+                var result = await this.BlobClient.GetBlobClient(blob.Name).DownloadContentAsync();
+                if (result.Value.Details.ContentLength == 0) {
+                    continue;
+                }
+
+                if (!blob.Name.StartsWith(prefix)) {
+                    this.Logger.LogWarning("Found prefix mismatch for seed id {seedId}, blob name {blobName}", seedId, blob.Name);
+                    continue;
+                }
+
+                var suffix = blob.Name.Substring(prefix.Length);
+
+                data[suffix] = result.Value.Content;
+            }
+
+            return data;
+        }
+    }
+}