Improve look of graphs

app/routes/main.py

@@ -235,12 +235,45 @@ def generate_weekly_calendar(readings_by_day, selected_date, local_tz):
     ]
 
 def prepare_graph_data(readings):
-    """Prepare data for graph rendering."""
+    """Prepare data for graph rendering, reversing so chronological order is left-to-right."""
+    chronological_readings = list(reversed(readings))
+    
+    n = len(chronological_readings)
+    time_percentages = []
+    
+    systolic_vals = [r.systolic for r in chronological_readings]
+    diastolic_vals = [r.diastolic for r in chronological_readings]
+    hr_vals = [r.heart_rate for r in chronological_readings]
+    
+    sys_avg = round(sum(systolic_vals) / n, 1) if n > 0 else 0
+    dia_avg = round(sum(diastolic_vals) / n, 1) if n > 0 else 0
+    hr_avg = round(sum(hr_vals) / n, 1) if n > 0 else 0
+    
+    if n == 0:
+        pass
+    elif n == 1:
+        time_percentages = [0.5]
+    else:
+        first_time = chronological_readings[0].timestamp.timestamp()
+        last_time = chronological_readings[-1].timestamp.timestamp()
+        time_span = last_time - first_time
+        
+        for r in chronological_readings:
+            if time_span == 0:
+                time_percentages.append(0.5)
+            else:
+                p = (r.timestamp.timestamp() - first_time) / time_span
+                time_percentages.append(p)
+
     return {
-        'timestamps': [r.timestamp.strftime('%b %d') for r in readings],
-        'systolic': [r.systolic for r in readings],
-        'diastolic': [r.diastolic for r in readings],
-        'heart_rate': [r.heart_rate for r in readings],
+        'timestamps': [r.timestamp.strftime('%b %d\n%H:%M') for r in chronological_readings],
+        'systolic': systolic_vals,
+        'diastolic': diastolic_vals,
+        'heart_rate': hr_vals,
+        'time_percentages': time_percentages,
+        'sys_avg': sys_avg,
+        'dia_avg': dia_avg,
+        'hr_avg': hr_avg,
     }
 
 def calculate_progress_badges(user_id, user_tz):