elkay: lesson.py and teacher link

phase/Student_view/teacherlink.py

@@ -214,18 +214,33 @@ def show_code():
 
                     c1, c2 = st.columns(2)
                     with c1:
-                        # pass lesson & assignment to the Lessons page
                         if st.button("▶️ Start Lesson", key=f"start_lesson_{r.get('assignment_id')}"):
-                            st.session_state.selected_lesson = int(r.get("lesson_id"))          # keep for backward compat
-                            st.session_state.selected_assignment = int(r.get("assignment_id"))  # keep for backward compat
-
-                            # New explicit route hint. This is what fixes your navigation.
+                            lesson_id = int(r.get("lesson_id"))
+                            assignment_id = int(r.get("assignment_id"))
+
+                            # 1) Tell backend this assignment has started
+                            try:
+                                _mark_assignment_started(student_id, assignment_id)
+                                # 2) Nudge a first position so the bar moves from 0%
+                                _set_assignment_progress(student_id, assignment_id, current_pos=1, progress=0.05)
+                            except Exception as e:
+                                st.warning(f"Could not mark as started yet. Continuing anyway. {e}")
+
+                            # 3) Navigate
+                            st.session_state.selected_lesson = lesson_id
+                            st.session_state.selected_assignment = assignment_id
                             st.session_state.lesson_route = {
                                 "source": "teacher",
-                                "lesson_id": int(r.get("lesson_id")),
-                                "assignment_id": int(r.get("assignment_id") or 0),
+                                "lesson_id": lesson_id,
+                                "assignment_id": assignment_id,
                             }
 
+                            # Optional: clear any cached data so the updated status shows next render
+                            try:
+                                st.cache_data.clear()
+                            except Exception:
+                                pass
+
                             st.session_state.current_page = "Lessons"
                             st.rerun()
                     with c2:

utils/api.py

@@ -328,6 +328,18 @@ def create_quiz(lesson_id: int, title: str, items: list[dict], settings: dict):
     }).json()
     return d.get("quiz_id", d.get("id", d))
 
+def mark_assignment_started(student_id: int, assignment_id: int):
+    return _req("POST", f"/assignments/{assignment_id}/start",
+                json={"student_id": student_id}).json()
+
+def set_assignment_progress(student_id: int, assignment_id: int,
+                            current_pos: int, progress: float):
+    return _req("PATCH", f"/assignments/{assignment_id}/progress",
+                json={"student_id": student_id,
+                      "current_pos": current_pos,
+                      "progress": progress}).json()
+
+
 # def get_quiz(quiz_id: int):
 #     return _json_or_raise(_req("GET", f"/quizzes/{quiz_id}"))