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/redeem.py

@@ -0,0 +1,94 @@
+from .error import NoData, RedeemUnavailable
+from .item import ItemFactory
+
+
+class Redeem:
+    def __init__(self, c=None) -> None:
+        self.c = c
+        self.code: str = None
+        self.redeem_type: int = None
+
+        self.items: list = []
+        self.fragment: int = None
+
+    def select(self, code: str = None) -> None:
+        if code:
+            self.code = code
+        self.c.execute('''select * from redeem where code=:a''',
+                       {'a': self.code})
+        x = self.c.fetchone()
+        if x is None:
+            raise NoData('The redeem `%s` does not exist.' % self.code, 504)
+
+        self.redeem_type = x[1]
+
+    def select_items(self) -> None:
+        self.c.execute('''select * from redeem_item where code=:a''',
+                       {'a': self.code})
+        x = self.c.fetchall()
+        if not x:
+            raise NoData(
+                'The redeem `%s` does not have any items.' % self.code)
+        self.items = [ItemFactory.from_dict({
+            'item_id': i[1],
+            'type': i[2],
+            'amount': i[3] if i[3] else 1
+        }, self.c) for i in x]
+
+
+class UserRedeem(Redeem):
+    '''
+        用户兑换码类\ 
+        properties: `user` - `User`类或子类的实例
+    '''
+
+    def __init__(self, c=None, user=None) -> None:
+        super().__init__(c)
+        self.user = user
+
+    @property
+    def is_available(self) -> bool:
+        if self.redeem_type is None:
+            self.select()
+
+        if self.redeem_type == 0:
+            # 一次性
+            self.c.execute(
+                '''select exists(select * from user_redeem where code=:a)''', {'a': self.code})
+            if self.c.fetchone() == (1,):
+                return False
+        elif self.redeem_type == 1:
+            # 每个玩家一次
+            self.c.execute('''select exists(select * from user_redeem where code=:a and user_id=:b)''',
+                           {'a': self.code, 'b': self.user.user_id})
+            if self.c.fetchone() == (1,):
+                return False
+
+        return True
+
+    def insert_user_redeem(self) -> None:
+        self.c.execute('''insert into user_redeem values(:b,:a)''',
+                       {'a': self.code, 'b': self.user.user_id})
+
+    def claim_user_redeem(self, code: str = None) -> None:
+        if code:
+            self.code = code
+        if not self.is_available:
+            if self.redeem_type == 0:
+                raise RedeemUnavailable(
+                    'The redeem `%s` is unavailable.' % self.code)
+            elif self.redeem_type == 1:
+                raise RedeemUnavailable(
+                    'The redeem `%s` is unavailable.' % self.code, 506)
+
+        if not self.items:
+            self.select_items()
+
+        self.insert_user_redeem()
+
+        self.fragment = 0
+        for i in self.items:
+            if i.item_type == 'fragment':
+                self.fragment += i.amount
+            else:
+                i.user_claim_item(self.user)