Optimize computation

Signed-off-by: Emmy D'Anello <ynerant@emy.lu>

app.py

@@ -120,8 +120,11 @@ def parse_trains(flush: bool = False, verbose: bool = False):
     with open('tgvmax.csv') as f:
         first_line = True
         already_seen = set()
+        already_updated = set(x[0] for x in db.session.query(Train).filter(Train.last_modification > last_modification)\
+                .values(Train.id))
         for line in (tqdm if verbose else lambda x: x)(csv.reader(f, delimiter=';')):
             if first_line:
+                # Skip first line
                 first_line = False
                 continue
 
@@ -134,6 +137,10 @@ def parse_trains(flush: bool = False, verbose: bool = False):
                     print("Duplicate:", train_id)
                 continue
 
+            if train_id in already_updated:
+                # Already updated by the simulator
+                continue
+
             train = Train(
                 id=train_id,
                 day=date.fromisoformat(line[0]),
@@ -162,62 +169,57 @@ def parse_trains(flush: bool = False, verbose: bool = False):
 
 
 def find_routes(day: date | datetime, origin: str, destination: str | None,
-                verbose: bool = False):
+                verbose: bool = False, min_dep: time = time(0, 0),
+                explored: dict | None = None):
     if isinstance(day, datetime):
         day = day.date()
 
-    trains = db.session.query(Train).filter_by(day=day, tgvmax=True).all()
+    if explored is None:
+        explored = {}
+
+    if origin not in explored:
+        explored[origin] = (min_dep, None)
+        valid_routes = []
+        max_dep = time(23, 59)
+    else:
+        max_dep, valid_routes = explored[origin]
+        if max_dep < min_dep:
+            # Already parsed these trains
+            return {destination: valid_routes}
+        explored[origin] = min_dep, None
+
+    trains = db.session.query(Train).filter_by(day=day, tgvmax=True, orig=origin)\
+            .filter(Train.dep >= min_dep, Train.dep < max_dep).all()
+    if not trains:
+        # No train in the requested interval
+        explored[origin] = (min_dep, valid_routes)
+        return {destination: valid_routes}
 
     trains.sort(key=lambda train: train.dep)
-
-    # For better results later, fetch all trains from the origin or to the destination
-    # This is not exhaustive, but can be a good approximation
-    queue_routes(day, origin=origin, verbose=verbose, autocommit=False)
-    if destination:
-        queue_routes(day, destination=destination, verbose=verbose, autocommit=False)
-
     db.session.commit()
 
-    per_arr_explore = {}
-    valid_routes = []
-
-    for train in (t := tqdm(trains) if verbose else trains):
-        if train.orig == origin:
-            # Update from the TGVMax simulator
-            queue_route(day, train.orig_iata, train.dest_iata, verbose, False)
-
-            it = [train]
+    for train in (t := tqdm(trains, desc=origin) if verbose else trains):
         if train.dest == destination:
             # We hope that we have a direct train
-                valid_routes.append(it)
+            valid_routes.append([train])
         else:
-                per_arr_explore.setdefault(train.dest, [])
-                per_arr_explore[train.dest].append(it)
+            if train.dest in explored and explored[train.dest][1] is None:
+                # This is a loop
                 continue
-
-        for it in list(per_arr_explore.get(train.orig, [])):
-            if any(train.dest == tr.dest or train.dest == origin for tr in it):
-                # Avoid loops
+            elif train.arr < min_dep:
+                # The train is not direct and arrives on the next day, we avoid that
                 continue
+            find_routes(day, train.dest, destination, verbose, train.arr, explored)
 
-            last_train = it[-1]
+            # Filter unusuable trains
+            valid_routes += [[train] + it for it in explored[train.dest][1] if it[0].dep >= train.arr]
 
-            if last_train.arr <= train.dep:
-                # Update from the TGVMax simulator, this line can be useful later
-                queue_route(day, train.orig_iata, train.dest_iata, verbose, False)
-
-                new_it = it + [train]
-                if train.dest == destination:
-                    # Goal is achieved
-                    valid_routes.append(new_it)
-                else:
-                    per_arr_explore.setdefault(train.dest, [])
-                    per_arr_explore[train.dest].append(new_it)
+    explored[origin] = (min_dep, valid_routes)
 
     # Send queued trains to the database
     db.session.commit()
 
-    return {destination: valid_routes} if destination else per_arr_explore
+    return {destination: valid_routes} if destination else {}
 
 
 # Don't use the decorator to keep the function callable
@@ -241,18 +243,13 @@ def queue_route(day: date | datetime, origin: str, destination: str, verbose: bo
     if isinstance(day, datetime):
         day = day.date()
 
-    query = db.session.query(RouteQueue).filter_by(day=day, origin=origin, destination=destination, response_time=None)
-    if query.count():
-        return
-
-    query = db.session.query(RouteQueue).filter(RouteQueue.day == day,
-                                                RouteQueue.origin == origin,
-                                                RouteQueue.destination == destination,
-                                                RouteQueue.expiration_time >= datetime.now(timezone('UTC')))
+    query = db.session.query(RouteQueue).filter_by(day=day, origin=origin, destination=destination)\
+            .filter((RouteQueue.response_time == None) | (RouteQueue.expiration_time >= datetime.now(timezone('UTC'))))
     if query.count():
         return
 
     db.session.add(RouteQueue(day=day, origin=origin, destination=destination))
+    if autocommit:
         db.session.commit()
 
 
@@ -270,6 +267,10 @@ def queue_routes(day: date | datetime, origin: str | None = None,
     if isinstance(day, datetime):
         day = day.date()
 
+    valid_routes = set(db.session.query(RouteQueue).filter_by(day=day)\
+            .filter((RouteQueue.response_time == None) | (RouteQueue.expiration_time >= datetime.now(timezone('UTC'))))\
+            .values(RouteQueue.origin, RouteQueue.destination))
+
     query = db.session.query(Train).filter((Train.day == day))
     if origin:
         query = query.filter((Train.orig_iata == origin) | (Train.orig == origin))
@@ -279,7 +280,9 @@ def queue_routes(day: date | datetime, origin: str | None = None,
     for train in (t := tqdm(query) if verbose else query):
         if verbose:
             t.set_description(f"{day}: {train.orig} --> {train.dest}")
+        if (train.orig_iata, train.dest_iata) not in valid_routes:
             queue_route(day, train.orig_iata, train.dest_iata, verbose, autocommit)
+            valid_routes.add((train.orig_iata, train.dest_iata))
 
 
 # Same as above