initial project

controller/conflict_checker/teacher_conflict_checker.py

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+"""
+Verifies that no instructor is booked into two sessions at the same
+day+slot (whether both are lectures, both labs, or a mix of either).
+
+Like student_conflict_checker, this re-derives occupancy directly from the
+session list rather than trusting the scheduler's internal busy-maps.
+"""
+
+from collections import defaultdict
+
+
+def check_teacher_conflicts(sessions):
+    """
+    Returns a list of conflict dicts, one per (instructor_code, day, slot)
+    where two or more sessions overlap for that instructor:
+        {
+            "instructor_code": str,
+            "day": str,
+            "slot_index": int,
+            "sessions": [session, session, ...],
+        }
+    """
+    # (instructor_code, day, slot_index) -> list of sessions occupying that cell
+    occupied = defaultdict(list)
+
+    for session in sessions:
+        day = session["day"]
+        instructor_code = session["instructor_code"]
+        for slot_index in session["slot_indices"]:
+            occupied[(instructor_code, day, slot_index)].append(session)
+
+    conflicts = []
+    for (instructor_code, day, slot_index), cell_sessions in occupied.items():
+        if len(cell_sessions) > 1:
+            conflicts.append({
+                "instructor_code": instructor_code,
+                "day": day,
+                "slot_index": slot_index,
+                "sessions": cell_sessions,
+            })
+
+    conflicts.sort(key=lambda c: (c["instructor_code"], c["day"], c["slot_index"]))
+    return conflicts
+
+
+def format_teacher_conflicts(conflicts):
+    """Human-readable lines describing each teacher conflict."""
+    lines = []
+    for c in conflicts:
+        course_list = ", ".join(
+            f'{s["course_id"]} ({s["course_type"]}) for batch(es) {"+".join(s["batch_codes"])} in {s["room_id"]}'
+            for s in c["sessions"]
+        )
+        instructor_name = c["sessions"][0]["instructor_name"]
+        lines.append(
+            f'Instructor {instructor_name} ({c["instructor_code"]}) is double-booked on '
+            f'{c["day"]} slot {c["slot_index"]}: {course_list}'
+        )
+    return lines