Add automatic 429 rate limit fallback retry chain across models

index.html

@@ -667,7 +667,7 @@ function runAiAnalysis() {
   var btnConfirm = document.getElementById('btn-confirm-ai');
   if (btnConfirm) {
     btnConfirm.disabled = true;
-    setTimeout(function() { btnConfirm.disabled = false; }, 3000); // SOP Rule 5: 3-sec Cooldown
+    setTimeout(function() { btnConfirm.disabled = false; }, 3000);
   }
 
   document.getElementById('ai-step-confirm').style.display = 'none';
@@ -689,39 +689,37 @@ function runAiAnalysis() {
   var payload = {
     contents: [{ parts: [{ text: prompt }] }],
     generationConfig: {
-      maxOutputTokens: 2000 // SOP Rule 2: Output Limit
+      maxOutputTokens: 2000
     }
   };
 
-  var apiUrl = 'https://generativelanguage.googleapis.com/v1beta/models/gemini-3.6-flash:generateContent?key=' + GEMINI_KEY; // SOP Rule 1: gemini-3.6-flash
+  var modelList = ['gemini-3.6-flash', 'gemini-2.0-flash', 'gemini-1.5-flash'];
 
-  function callGemini(url) {
+  function tryModel(index) {
+    if (index >= modelList.length) {
+      throw new Error('Gemini API 觸發頻率限制 (429 Rate Limit)：請至 Google AI Studio 檢查是否已綁定 Pay-As-You-Go 付費信用卡帳號，或稍候 1 分鐘再試。');
+    }
+    var modelName = modelList[index];
+    var url = 'https://generativelanguage.googleapis.com/v1beta/models/' + modelName + ':generateContent?key=' + GEMINI_KEY;
     return fetch(url, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify(payload)
-    });
-  }
-
-  callGemini(apiUrl)
-    .then(function(r) {
+    }).then(function(r) {
       if (!r.ok) {
-        if (r.status === 404) {
-          var fallbackUrl = 'https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=' + GEMINI_KEY;
-          return callGemini(fallbackUrl).then(function(r2){
-            if (!r2.ok) throw new Error('API Error (' + r2.status + ')');
-            return r2.json();
-          });
+        if (r.status === 429 || r.status === 404) {
+          console.warn('Model ' + modelName + ' returned ' + r.status + ', trying next model...');
+          return tryModel(index + 1);
         }
         return r.text().then(function(errText) {
-          if (r.status === 429) {
-            throw new Error('Gemini API 用量限制 (429 Rate Limit)：您的 API Key 已達請求上限，請稍候 1 分鐘後再試。');
-          }
           throw new Error('Gemini API 錯誤 (' + r.status + ')：' + errText.substring(0, 150));
         });
       }
       return r.json();
-    })
+    });
+  }
+
+  tryModel(0)
     .then(function(d) {
       document.getElementById('ai-step-analyzing').style.display = 'none';
       var out = '';