phases initial

app/template_generator.py

@@ -22,11 +22,11 @@ sys.path.insert(0, os.path.join(ROOT_DIR, "templates", "room-wise"))
 sys.path.insert(0, os.path.join(ROOT_DIR, "templates", "student-wise"))
 sys.path.insert(0, os.path.join(ROOT_DIR, "templates", "teacher-wise"))
 
-from template_controller import build_schedule  # noqa: E402
+from template_controller import load_data, Scheduler  # noqa: E402
 from conflict_checker import check_all_conflicts  # noqa: E402
 from conflict_checker.student_conflict_checker import format_student_conflicts  # noqa: E402
 from conflict_checker.teacher_conflict_checker import format_teacher_conflicts  # noqa: E402
-from template_logger import reset_log, log_error, log_info  # noqa: E402
+from template_logger import reset_log, log_error, log_info, log_warning  # noqa: E402
 
 from batch_wise_template import generate_batch_wise_templates  # noqa: E402
 from department_wise_template import generate_department_wise_templates  # noqa: E402
@@ -38,6 +38,23 @@ RESULT_DIR = os.path.join(ROOT_DIR, "result", "templates")
 VIEW_NAMES = ["batch-wise", "department-wise", "room-wise", "student-wise", "teacher-wise"]
 
 
+def _check_and_log(sessions, label):
+    """Runs student + teacher conflict checks over `sessions` and logs the result."""
+    report = check_all_conflicts(sessions)
+    if report["has_conflicts"]:
+        for line in format_student_conflicts(report["student_conflicts"]):
+            log_error(f"[{label}] STUDENT CONFLICT: {line}")
+        for line in format_teacher_conflicts(report["teacher_conflicts"]):
+            log_error(f"[{label}] TEACHER CONFLICT: {line}")
+        log_warning(
+            f"[{label}] Found {len(report['student_conflicts'])} student conflict(s) and "
+            f"{len(report['teacher_conflicts'])} teacher conflict(s)."
+        )
+    else:
+        log_info(f"[{label}] No conflicts found — clash-free.")
+    return report
+
+
 def clear_result_dir():
     """Removes every previous run's output so stale files never linger."""
     for view_name in VIEW_NAMES:
@@ -59,23 +76,32 @@ def main():
         generate_dummy_data()
         print()
 
-    print("Loading data and building clash-free schedule...")
-    data, sessions = build_schedule()
-    print(f"Scheduled {len(sessions)} sessions.\n")
+    log_info("Loading data...")
+    data = load_data()
+    scheduler = Scheduler(data)
 
-    log_info("Running conflict checks (student/batch and teacher)...")
-    report = check_all_conflicts(sessions)
-    if report["has_conflicts"]:
-        for line in format_student_conflicts(report["student_conflicts"]):
-            log_error(f"STUDENT CONFLICT: {line}")
-        for line in format_teacher_conflicts(report["teacher_conflicts"]):
-            log_error(f"TEACHER CONFLICT: {line}")
-        log_error(
-            f"Found {len(report['student_conflicts'])} student conflict(s) and "
-            f"{len(report['teacher_conflicts'])} teacher conflict(s)."
-        )
-    else:
-        log_info("No conflicts found — schedule is clash-free for students and teachers.")
+    # --- Phase 1: general courses (Tue/Thu preferred), self-repaired until clash-free ---
+    log_info("Phase 1/3: scheduling general courses...")
+    phase1_sessions = scheduler.phase_1_general_courses()
+    _check_and_log(phase1_sessions, "Phase 1 (general courses)")
+
+    # --- Phase 2: labs, scheduled against Phase 1's fixed placements ---
+    log_info("Phase 2/3: scheduling labs...")
+    phase2_sessions = scheduler.phase_2_labs()
+    _check_and_log(phase1_sessions + phase2_sessions, "Phase 2 (general courses + labs)")
+
+    # --- Phase 3: remaining theory courses, batch by batch ---
+    log_info("Phase 3/3: scheduling remaining courses (batch by batch)...")
+    phase3_sessions = scheduler.phase_3_remaining_courses()
+
+    sessions = phase1_sessions + phase2_sessions + phase3_sessions
+    log_info(
+        f"Scheduling complete: {len(phase1_sessions)} general, {len(phase2_sessions)} lab, "
+        f"{len(phase3_sessions)} remaining = {len(sessions)} total session(s)."
+    )
+
+    log_info("Running final conflict check (student/batch and teacher) over the full schedule...")
+    _check_and_log(sessions, "Final (full schedule)")
 
     generators = [
         ("batch-wise", generate_batch_wise_templates),

controller/template_controller.py

@@ -2,17 +2,23 @@
 Loads dummy CSV data and builds a clash-free schedule of sessions that all
 five templates/*-wise template modules render from.
 
-Scheduling rules (dummy/demo scheduler, not a full CSP solver):
-  1. General courses (shared across every batch of a session) are placed
-     first, only on Tuesday, so those slots are locked in before anything
-     else and never clash across the batches sharing them. Each general
-     offering gets `lectures_per_week` sessions.
-  2. Lab courses are placed next: each offering gets `labs_per_week`
-     180-minute / double-slot sessions, in lab rooms only, on whichever
-     day/slot-pair is free for the batch, instructor, and room.
-  3. Remaining theory sessions (`lectures_per_week` per non-general
-     offering) fill the rest of the week (Mon/Tue/Wed/Thu/Fri), one
-     90-minute slot at a time, avoiding room / instructor / batch clashes.
+Scheduling is done in three sequential, independently-verified phases (see
+app/template_generator.py for the orchestration + per-phase conflict
+checks). Each phase's placements are locked before the next phase starts:
+once a (day, slot, room/instructor/batch) combination is marked busy by an
+earlier phase, later phases can never reuse it.
+
+  1. General courses (shared across every batch of a session), preferring
+     Tuesday/Thursday first. Each offering gets `lectures_per_week`
+     sessions. If two general courses still land in the same slot for a
+     batch, the losing session is moved to another day/slot until this
+     phase is clash-free (see `phase_1_general_courses`).
+  2. Labs: each offering gets `labs_per_week` 180-minute / double-slot
+     sessions, in lab rooms only, scheduled against Phase 1's fixed
+     placements plus labs placed so far this phase.
+  3. Remaining (non-general) theory sessions, scheduled batch by batch in
+     sorted batch_code order: for each batch, every one of its remaining
+     offerings is placed and locked before the next batch is considered.
 
 Room selection always tries a course's preferred lecture_room_id /
 lab_room_id first, falling back to another same-type room only if the
@@ -131,6 +137,13 @@ class Scheduler:
         self.instructor_busy.setdefault(key, set()).add(instructor_code)
         self.batch_busy.setdefault(key, set()).update(batch_codes)
 
+    def _unmark_busy(self, day, slot_index, room_id, instructor_code, batch_codes):
+        key = (day, slot_index)
+        self.room_busy.get(key, set()).discard(room_id)
+        self.instructor_busy.get(key, set()).discard(instructor_code)
+        for b in batch_codes:
+            self.batch_busy.get(key, set()).discard(b)
+
     def _room_candidates(self, preferred_room_id, room_pool):
         """Preferred room first, then the rest of the same-type pool."""
         preferred = self.data["rooms_by_id"].get(preferred_room_id)
@@ -142,7 +155,7 @@ class Scheduler:
         start = TIME_SLOTS[slot_indices[0]]["start"]
         end = TIME_SLOTS[slot_indices[-1]]["end"]
         session_type = "lab" if len(slot_indices) > 1 else "theory"
-        self.sessions.append({
+        session = {
             "day": day,
             "slot_indices": slot_indices,
             "start": start,
@@ -157,34 +170,84 @@ class Scheduler:
             "room_id": room["room_id"],
             "room_name": room["room_name"],
             "batch_codes": offering["batch_codes"],
-        })
+        }
+        self.sessions.append(session)
+        return session
 
-    def schedule_general_courses(self):
+    def _place_theory_session(self, offering, room_candidates, day_order):
+        """Finds and locks a free single-slot session; returns the session dict or None."""
+        for day in day_order:
+            for slot_index in TEACHING_SLOT_INDICES:
+                for room in room_candidates:
+                    if self._is_free(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"]):
+                        self._mark_busy(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"])
+                        return self._add_session(offering, day, [slot_index], room)
+        return None
+
+    def phase_1_general_courses(self, preferred_days=("Tuesday", "Thursday"), max_repair_attempts=20):
+        """
+        Places every general-course offering's weekly lectures, preferring
+        `preferred_days` first. Afterwards, self-repairs: any batch left
+        with two general-course sessions in the same slot has the losing
+        session unmarked and re-placed (scanning every day) until this
+        phase's own sessions are clash-free. Returns this phase's sessions.
+        """
         general = [o for o in self.data["offerings"] if o["course"]["is_general"]]
+        preferred_order = list(preferred_days) + [d for d in DAYS if d not in preferred_days]
+        phase_start = len(self.sessions)
+
         for offering in general:
             course = offering["course"]
             room_candidates = self._room_candidates(course["lecture_room_id"], self.classrooms)
-
             for _ in range(course["lectures_per_week"]):
-                placed = False
-                # Tuesday first, then spill to the rest of the week if a
-                # session can't fit there.
-                for day in ["Tuesday"] + [d for d in DAYS if d != "Tuesday"]:
-                    for slot_index in TEACHING_SLOT_INDICES:
-                        for room in room_candidates:
-                            if self._is_free(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"]):
-                                self._mark_busy(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"])
-                                self._add_session(offering, day, [slot_index], room)
-                                placed = True
-                                break
-                        if placed:
-                            break
-                    if placed:
-                        break
-                if not placed:
+                session = self._place_theory_session(offering, room_candidates, preferred_order)
+                if session is None:
                     print(f"WARNING: could not place a lecture for general course {offering['course_id']} section {offering['section_id']}")
 
-    def schedule_lab_courses(self):
+        phase_sessions = self.sessions[phase_start:]
+        self._repair_general_conflicts(phase_sessions, preferred_order, max_repair_attempts)
+        return phase_sessions
+
+    def _repair_general_conflicts(self, phase_sessions, day_order, max_attempts):
+        """Moves general-course sessions that clash for a batch to a free slot on any day."""
+        from conflict_checker.student_conflict_checker import check_student_conflicts
+
+        any_day_order = list(DAYS)
+        for _ in range(max_attempts):
+            conflicts = check_student_conflicts(phase_sessions)
+            if not conflicts:
+                return
+
+            # Re-place the last session involved in the first conflict; the
+            # other session(s) in that cell stay put.
+            losing_session = conflicts[0]["sessions"][-1]
+            offering = next(
+                o for o in self.data["offerings"]
+                if o["course_id"] == losing_session["course_id"] and o["section_id"] == losing_session["section_id"]
+            )
+            self._unmark_busy(
+                losing_session["day"], losing_session["slot_indices"][0],
+                losing_session["room_id"], losing_session["instructor_code"], losing_session["batch_codes"],
+            )
+            self.sessions.remove(losing_session)
+            phase_sessions.remove(losing_session)
+
+            room_candidates = self._room_candidates(offering["course"]["lecture_room_id"], self.classrooms)
+            new_session = self._place_theory_session(offering, room_candidates, any_day_order)
+            if new_session is None:
+                print(f"WARNING: could not repair general-course conflict for {offering['course_id']} section {offering['section_id']}")
+                return
+            phase_sessions.append(new_session)
+
+        print("WARNING: general-course conflicts remained unresolved after max repair attempts")
+
+    def phase_2_labs(self):
+        """
+        Places every lab offering's weekly labs into lab rooms, treating
+        Phase 1's placements (already marked busy) as fixed. Returns this
+        phase's sessions.
+        """
+        phase_start = len(self.sessions)
         offerings = [o for o in self.data["offerings"] if not o["course"]["is_general"] and o["course"]["labs_per_week"] > 0]
         for offering in offerings:
             course = offering["course"]
@@ -209,33 +272,37 @@ class Scheduler:
                 if not placed:
                     print(f"WARNING: could not place a lab for course {offering['course_id']} section {offering['section_id']} ({offering['batch_codes']})")
 
-    def schedule_theory_courses(self):
-        offerings = [o for o in self.data["offerings"] if not o["course"]["is_general"]]
-        for offering in offerings:
-            course = offering["course"]
-            room_candidates = self._room_candidates(course["lecture_room_id"], self.classrooms)
+        return self.sessions[phase_start:]
 
-            for _ in range(course["lectures_per_week"]):
-                placed = False
-                for day in DAYS:
-                    for slot_index in TEACHING_SLOT_INDICES:
-                        for room in room_candidates:
-                            if self._is_free(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"]):
-                                self._mark_busy(day, slot_index, room["room_id"], offering["instructor_code"], offering["batch_codes"])
-                                self._add_session(offering, day, [slot_index], room)
-                                placed = True
-                                break
-                        if placed:
-                            break
-                    if placed:
-                        break
-                if not placed:
-                    print(f"WARNING: could not place a lecture for course {offering['course_id']} section {offering['section_id']} ({offering['batch_codes']})")
+    def phase_3_remaining_courses(self):
+        """
+        Places every remaining (non-general) theory offering's weekly
+        lectures, batch by batch in sorted batch_code order: all of one
+        batch's offerings are placed and locked before the next batch is
+        considered. Treats Phases 1+2 (already marked busy) as fixed.
+        Returns this phase's sessions.
+        """
+        phase_start = len(self.sessions)
+        offerings = [o for o in self.data["offerings"] if not o["course"]["is_general"]]
+
+        for batch in sorted(self.data["batches"], key=lambda b: b["batch_code"]):
+            batch_code = batch["batch_code"]
+            batch_offerings = [o for o in offerings if batch_code in o["batch_codes"]]
+
+            for offering in batch_offerings:
+                course = offering["course"]
+                room_candidates = self._room_candidates(course["lecture_room_id"], self.classrooms)
+                for _ in range(course["lectures_per_week"]):
+                    session = self._place_theory_session(offering, room_candidates, DAYS)
+                    if session is None:
+                        print(f"WARNING: could not place a lecture for course {offering['course_id']} section {offering['section_id']} ({offering['batch_codes']})")
+
+        return self.sessions[phase_start:]
 
     def run(self):
-        self.schedule_general_courses()
-        self.schedule_lab_courses()
-        self.schedule_theory_courses()
+        self.phase_1_general_courses()
+        self.phase_2_labs()
+        self.phase_3_remaining_courses()
         return self.sessions
 
 

logs/template_generator.log

@@ -1,4 +1,11 @@
-Timetable generation log - started 2026-09-09T17:48:16.013663
+Timetable generation log - started 2026-09-09T17:59:37.068314
 ================================================================================
-[17:48:16] INFO: Running conflict checks (student/batch and teacher)...
-[17:48:16] INFO: No conflicts found — schedule is clash-free for students and teachers.
+[17:59:37] INFO: Loading data...
+[17:59:37] INFO: Phase 1/3: scheduling general courses...
+[17:59:37] INFO: [Phase 1 (general courses)] No conflicts found — clash-free.
+[17:59:37] INFO: Phase 2/3: scheduling labs...
+[17:59:37] INFO: [Phase 2 (general courses + labs)] No conflicts found — clash-free.
+[17:59:37] INFO: Phase 3/3: scheduling remaining courses (batch by batch)...
+[17:59:37] INFO: Scheduling complete: 6 general, 10 lab, 20 remaining = 36 total session(s).
+[17:59:37] INFO: Running final conflict check (student/batch and teacher) over the full schedule...
+[17:59:37] INFO: [Final (full schedule)] No conflicts found — clash-free.