chore: update download page to v1.0.22

- Retry up to 3 times with exponential backoff on 503/UNAVAILABLE
- Fall back to gemini-2.0-flash on final attempt
- Replace raw JSON error with user-friendly Japanese message

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/services/gemini_service.dart

@@ -261,14 +261,9 @@ $extractedText
       throw Exception('Gemini API Key is missing. Please set GEMINI_API_KEY.');
     }
 
-    final model = GenerativeModel(
-      model: 'gemini-2.5-flash', // ⚠️ FIXED MODEL NAME - DO NOT CHANGE without explicit user approval (confirmed working on 2026-01-17)
-      apiKey: apiKey,
-      generationConfig: GenerationConfig(
-        responseMimeType: 'application/json',
-        temperature: 0.2, // チャート一貫性向上のため 0.4→0.2 に変更 (2026-02-09)
-      ),
-    );
+    // モデル候補: 503/UNAVAILABLE 時にフォールバック
+    const primaryModel = 'gemini-2.5-flash';   // ⚠️ FIXED - confirmed 2026-01-17
+    const fallbackModel = 'gemini-2.0-flash';  // 503 連続時のフォールバック
 
     // Prepare Prompt
     final promptText = customPrompt ?? '''
@@ -296,37 +291,74 @@ $extractedText
 値が不明な場合は null または 適切な推測値を入れてください。
 ''';
 
-    // Prepare Content
+    // Prepare Content parts (画像バイト読み込みは一度だけ)
     final contentParts = <Part>[TextPart(promptText)];
     for (var path in imagePaths) {
-      // 撮影時に圧縮済み
       final bytes = await File(path).readAsBytes();
       contentParts.add(DataPart('image/jpeg', bytes));
     }
 
-    try {
-      final response = await model.generateContent([Content.multi(contentParts)]);
+    // 503 時: リトライ（指数バックオフ）→ フォールバックモデル
+    const maxRetries = 3;
+    final modelsToTry = [primaryModel, primaryModel, primaryModel, fallbackModel];
 
-      final jsonString = response.text;
-      if (jsonString == null) throw Exception('Empty response from Gemini');
+    for (int attempt = 0; attempt <= maxRetries; attempt++) {
+      final modelName = modelsToTry[attempt];
+      final isLastAttempt = attempt == maxRetries;
 
-      final jsonMap = jsonDecode(jsonString);
-      final result = SakeAnalysisResult.fromJson(jsonMap);
+      try {
+        if (attempt > 0) {
+          final waitSec = attempt == maxRetries ? 2 : (attempt * 3);
+          debugPrint('Retry $attempt/$maxRetries (model: $modelName, wait: ${waitSec}s)...');
+          await Future.delayed(Duration(seconds: waitSec));
+        }
 
-      // 3. キャッシュに保存（次回は即座に返せる）
-      if (imagePaths.isNotEmpty) {
-        final imageHash = await AnalysisCacheService.computeCombinedHash(imagePaths);
-        await AnalysisCacheService.saveCache(imageHash, result);
-        // 4. 銘柄名インデックスに登録（v1.0.15: チャート一貫性向上）
-        await AnalysisCacheService.registerBrandIndex(result.name, imageHash);
+        final model = GenerativeModel(
+          model: modelName,
+          apiKey: apiKey,
+          generationConfig: GenerationConfig(
+            responseMimeType: 'application/json',
+            temperature: 0.2,
+          ),
+        );
+
+        final response = await model.generateContent([Content.multi(contentParts)]);
+
+        final jsonString = response.text;
+        if (jsonString == null) throw Exception('Empty response from Gemini');
+
+        final jsonMap = jsonDecode(jsonString);
+        final result = SakeAnalysisResult.fromJson(jsonMap);
+
+        // 3. キャッシュに保存（次回は即座に返せる）
+        if (imagePaths.isNotEmpty) {
+          final imageHash = await AnalysisCacheService.computeCombinedHash(imagePaths);
+          await AnalysisCacheService.saveCache(imageHash, result);
+          // 4. 銘柄名インデックスに登録（v1.0.15: チャート一貫性向上）
+          await AnalysisCacheService.registerBrandIndex(result.name, imageHash);
+        }
+
+        if (attempt > 0) debugPrint('Succeeded on attempt $attempt (model: $modelName)');
+        return result;
+
+      } catch (e) {
+        final errStr = e.toString();
+        final is503 = errStr.contains('503') || errStr.contains('UNAVAILABLE') || errStr.contains('high demand');
+        debugPrint('Direct API Error (attempt $attempt, model: $modelName): $e');
+
+        if (isLastAttempt || !is503) {
+          // 最終試行 or 503以外のエラーはそのまま投げる
+          if (is503) {
+            throw Exception('AIサーバーが混雑しています。しばらく待ってから再試行してください。');
+          }
+          throw Exception('AI解析エラー(Direct): $e');
+        }
+        // 503 → 次のリトライへ
       }
-
-      return result;
-
-    } catch (e) {
-      debugPrint('Direct API Error: $e');
-      throw Exception('AI解析エラー(Direct): $e');
     }
+
+    // ここには到達しない
+    throw Exception('AI解析に失敗しました。再試行してください。');
   }
 }
 

web/download/releases.json

@@ -1,18 +1,18 @@
 {
     "date":  "2026-04-06",
-    "name":  "Ponshu Room 1.0.21 (2026-04-06)",
-    "version":  "v1.0.21",
+    "name":  "Ponshu Room 1.0.22 (2026-04-09)",
+    "version":  "v1.0.22",
     "apks":  {
                  "eiji":  {
                               "lite":  {
-                                           "url":  "https://posimai-lab.tail72e846.ts.net/mai/ponshu-room-lite/releases/download/v1.0.21/ponshu_room_consumer_eiji.apk",
+                                           "url":  "https://posimai-lab.tail72e846.ts.net/mai/ponshu-room-lite/releases/download/v1.0.22/ponshu_room_consumer_eiji.apk",
                                            "size_mb":  89,
                                            "filename":  "ponshu_room_consumer_eiji.apk"
                                        }
                           },
                  "maita":  {
                                "lite":  {
-                                            "url":  "https://posimai-lab.tail72e846.ts.net/mai/ponshu-room-lite/releases/download/v1.0.21/ponshu_room_consumer_maita.apk",
+                                            "url":  "https://posimai-lab.tail72e846.ts.net/mai/ponshu-room-lite/releases/download/v1.0.22/ponshu_room_consumer_maita.apk",
                                             "size_mb":  89,
                                             "filename":  "ponshu_room_consumer_maita.apk"
                                         }