Code refactoring

- Code refactoring
- Fix a bug that the other player will not become the host of the room at once, when the player disconnect in link play.

> Maybe add many unknown bugs. XD
> The song database `arcsong.db` will not used in the future. You can use a tool in `tool` folder to import old data.

latest version/core/constant.py

@@ -1,3 +1,6 @@
+from setting import Config
+
+
 class Constant:
 
     BAN_TIME = [1, 3, 7, 15, 31]
@@ -14,3 +17,18 @@ class Constant:
     ETO_UNCAP_BONUS_PROGRESS = 7
     LUNA_UNCAP_BONUS_PROGRESS = 7
     AYU_UNCAP_BONUS_PROGRESS = 5
+
+    MAX_FRIEND_COUNT = 50
+
+    BEST30_WEIGHT = 1 / 40
+    RECENT10_WEIGHT = 1 / 40
+
+    WORLD_MAP_FOLDER_PATH = './database/map/'
+    SONG_FILE_FOLDER_PATH = './database/songs/'
+
+    DOWNLOAD_TIMES_LIMIT = Config.DOWNLOAD_TIMES_LIMIT
+    DOWNLOAD_TIME_GAP_LIMIT = Config.DOWNLOAD_TIME_GAP_LIMIT
+    DOWNLOAD_LINK_PREFIX = Config.DOWNLOAD_LINK_PREFIX
+
+    LINK_PLAY_UNLOCK_LENGTH = 512
+    LINK_PLAY_TIMEOUT = 10