fix: renumber sets after delete and use last-logged values for prefill

Two bugs fixed:
- Deleting a set left gaps in set numbering (1, 3, 3). Now renumbers
  remaining sets sequentially after deletion.
- Logging set 1 caused the prefill to recalculate via the progression
  engine, shifting suggested reps mid-session. Now prefills from the
  last logged set's actual values; progression suggestion is only used
  for the first set of a session.

app/routes/logging.py

@@ -23,6 +23,30 @@ logger = structlog.get_logger(__name__)
 router = APIRouter(prefix="/log", tags=["logging"])
 
 
+def _get_prefill_values(
+    logs: list,
+    session: Session,
+    profile_id: int,
+    exercise_id: int,
+) -> tuple:
+    """Get pre-fill values for the next set form.
+
+    If sets have already been logged this session, use the last logged
+    set's values (users typically repeat the same reps/weight across sets).
+    Otherwise, use the progression engine's suggestion.
+
+    Returns:
+        (suggested_reps, suggested_weight) tuple.
+    """
+    if logs:
+        last = logs[-1]
+        return last.reps_completed, last.weight_used
+
+    progression = ProgressionService(session)
+    suggestion = progression.get_suggestion(profile_id, exercise_id)
+    return suggestion.get("suggested_reps"), suggestion.get("suggested_weight")
+
+
 @router.post("", response_class=HTMLResponse)
 async def log_set(
     request: Request,
@@ -80,10 +104,9 @@ async def log_set(
     # Return updated logs for this exercise
     logs = log_service.list_logs_for_exercise(ws.id, exercise_id)
     next_set = len(logs) + 1
-
-    # Fetch suggestion for pre-filling the next set form
-    progression = ProgressionService(session)
-    suggestion = progression.get_suggestion(active_profile_id, exercise_id)
+    suggested_reps, suggested_weight = _get_prefill_values(
+        logs, session, active_profile_id, exercise_id,
+    )
 
     templates = request.app.state.templates
     return templates.TemplateResponse("partials/log_entry.html", {
@@ -93,8 +116,8 @@ async def log_set(
         "workout_day_id": workout_day_id,
         "next_set": next_set,
         "session_id": ws.id,
-        "suggested_reps": suggestion.get("suggested_reps"),
-        "suggested_weight": suggestion.get("suggested_weight"),
+        "suggested_reps": suggested_reps,
+        "suggested_weight": suggested_weight,
     })
 
 
@@ -131,12 +154,12 @@ async def edit_log(
     logs = log_service.list_logs_for_exercise(log.session_id, log.exercise_id)
     next_set = len(logs) + 1
 
-    # Fetch suggestion for pre-filling the next set form
     active_profile_id = get_active_profile_id(request)
-    suggestion = {}
+    suggested_reps, suggested_weight = None, None
     if active_profile_id:
-        progression = ProgressionService(session)
-        suggestion = progression.get_suggestion(active_profile_id, log.exercise_id)
+        suggested_reps, suggested_weight = _get_prefill_values(
+            logs, session, active_profile_id, log.exercise_id,
+        )
 
     templates = request.app.state.templates
     return templates.TemplateResponse("partials/log_entry.html", {
@@ -146,8 +169,8 @@ async def edit_log(
         "workout_day_id": 0,
         "next_set": next_set,
         "session_id": log.session_id,
-        "suggested_reps": suggestion.get("suggested_reps"),
-        "suggested_weight": suggestion.get("suggested_weight"),
+        "suggested_reps": suggested_reps,
+        "suggested_weight": suggested_weight,
     })
 
 
@@ -180,12 +203,12 @@ async def delete_log(
         logs = log_service.list_logs_for_exercise(session_id, exercise_id)
         next_set = len(logs) + 1
 
-        # Fetch suggestion for pre-filling the next set form
         active_profile_id = get_active_profile_id(request)
-        suggestion = {}
+        suggested_reps, suggested_weight = None, None
         if active_profile_id:
-            progression = ProgressionService(session)
-            suggestion = progression.get_suggestion(active_profile_id, exercise_id)
+            suggested_reps, suggested_weight = _get_prefill_values(
+                logs, session, active_profile_id, exercise_id,
+            )
 
         templates = request.app.state.templates
         return templates.TemplateResponse("partials/log_entry.html", {
@@ -195,8 +218,8 @@ async def delete_log(
             "workout_day_id": 0,
             "next_set": next_set,
             "session_id": session_id,
-            "suggested_reps": suggestion.get("suggested_reps"),
-            "suggested_weight": suggestion.get("suggested_weight"),
+            "suggested_reps": suggested_reps,
+            "suggested_weight": suggested_weight,
         })
 
     return HTMLResponse("")