fix: improve load_assets error handling and logging

- Split data_tw and data_us loading into separate try-catch blocks
- Add detailed logging for successful loads and errors
- Ensure variables are always initialized to empty dict on failure
- Fix potential None value issue in strategy_tw route

main.py

@@ -63,11 +63,24 @@ def load_assets():
         try:
             with open('assets_tw.json') as f:
                 data_tw = json.load(f)
+            logger.info(f"Loaded assets_tw.json with {len(data_tw)} items")
+        except FileNotFoundError as e:
+            logger.warning(f"Assets file not found: {e}")
+            data_tw = {}
+        except Exception as e:
+            logger.error(f"Error loading assets_tw.json: {e}")
+            data_tw = {}
+
+    if data_us is None:
+        try:
             with open('assets_us.json') as f:
                 data_us = json.load(f)
+            logger.info(f"Loaded assets_us.json with {len(data_us)} items")
         except FileNotFoundError as e:
-            print(f"Warning: Assets file not found: {e}")
+            logger.warning(f"Assets file not found: {e}")
-            data_tw = {}
+            data_us = {}
+        except Exception as e:
+            logger.error(f"Error loading assets_us.json: {e}")
             data_us = {}
 
 def login_required():
@@ -234,6 +247,7 @@ def strategy():
     else:
         flash('使用投組功能請先登入。', 'warning')
         return redirect(url_for('login'))
+    load_assets()  # Ensure assets are loaded
     session['tw'] = 0
     return render_template('strategy_tw.html', data_us = data_us, data_tw=data_tw, stock=['TSLA'])
 
@@ -248,6 +262,7 @@ def strategy_tw():
     else:
         flash('使用投組功能請先登入。', 'warning')
         return redirect(url_for('login'))
+    load_assets()  # Ensure assets are loaded
     session['tw'] = 1
     return render_template('strategy_tw.html', data_tw=data_tw, stock=['2330.TW'])
 
@@ -625,6 +640,7 @@ def copy_portfolio():
         return redirect(url_for('login'))
     if not 'tw' in session:
         return redirect(url_for('index'))
+    load_assets()  # Ensure assets are loaded
     session['tw'] = 0
     return render_template('strategy_tw.html', data_us = data_us, data_tw=data_tw, stock=session['currStockList'])