use SQL's limit/offset pagination for nextIndex/maxCount requests (#185)

Instead of retrieving the entire list of items/characters/scores/etc. at once (and even store them in memory), use SQL's `LIMIT ... OFFSET ...` pagination so we only take what we need.

Currently only CHUNITHM uses this, but this will also affect maimai DX and O.N.G.E.K.I. once the PR is ready.

Also snuck in a fix for CHUNITHM/maimai DX's `GetUserRivalMusicApi` to respect the `userRivalMusicLevelList` sent by the client.

### How this works

Say we have a `GetUserCharacterApi` request:

```json
{
    "userId": 10000,
    "maxCount": 700,
    "nextIndex": 0
}
```

Instead of getting the entire character list from the database (which can be very large if the user force unlocked everything), add limit/offset to the query:

```python
select(character)
.where(character.c.user == user_id)
.order_by(character.c.id.asc())
.limit(max_count + 1)
.offset(next_index)
```

The query takes `maxCount + 1` items from the database to determine if there is more items than can be returned:

```python
rows = ...

if len(rows) > max_count:
    # return only max_count rows
    next_index += max_count
else:
    # return everything left
    next_index = -1
```

This has the benefit of not needing to load everything into memory (and also having to store server state, as seen in the [`SCORE_BUFFER` list](2274b42358/titles/chuni/base.py (L13)).)

Reviewed-on: Hay1tsme/artemis#185
Co-authored-by: beerpsi <beerpsi@duck.com>
Co-committed-by: beerpsi <beerpsi@duck.com>

titles/chuni/new.py

@@ -4,12 +4,14 @@ from random import randint
 from typing import Dict
 
 import pytz
+
 from core.config import CoreConfig
 from core.utils import Utils
-from titles.chuni.const import ChuniConstants
-from titles.chuni.database import ChuniData
 from titles.chuni.base import ChuniBase
 from titles.chuni.config import ChuniConfig
+from titles.chuni.const import ChuniConstants
+from titles.chuni.database import ChuniData
+
 
 class ChuniNew(ChuniBase):
     ITEM_TYPE = {"character": 20, "story": 21, "card": 22}
@@ -285,35 +287,37 @@ class ChuniNew(ChuniBase):
         }
 
     async def handle_get_user_printed_card_api_request(self, data: Dict) -> Dict:
-        user_print_list = await self.data.item.get_user_print_states(
-            data["userId"], has_completed=True
+        user_id = int(data["userId"])
+        next_idx = int(data["nextIndex"])
+        max_ct = int(data["maxCount"])
+
+        rows = await self.data.item.get_user_print_states(
+            user_id,
+            has_completed=True,
+            limit=max_ct + 1,
+            offset=next_idx,
         )
-        if user_print_list is None:
+        if rows is None or len(rows) == 0:
             return {
-                "userId": data["userId"],
+                "userId": user_id,
                 "length": 0,
                 "nextIndex": -1,
                 "userPrintedCardList": [],
             }
 
         print_list = []
-        next_idx = int(data["nextIndex"])
-        max_ct = int(data["maxCount"])
 
-        for x in range(next_idx, len(user_print_list)):
-            tmp = user_print_list[x]._asdict()
+        for row in rows[:max_ct]:
+            tmp = row._asdict()
             print_list.append(tmp["cardId"])
 
-            if len(print_list) >= max_ct:
-                break
-
-        if len(print_list) >= max_ct:
-            next_idx = next_idx + max_ct
+        if len(rows) > max_ct:
+            next_idx += max_ct
         else:
             next_idx = -1
 
         return {
-            "userId": data["userId"],
+            "userId": user_id,
             "length": len(print_list),
             "nextIndex": next_idx,
             "userPrintedCardList": print_list,