markov: Reply chance is loaded lazily

Just like the actual chain data structure, this value is now loaded
lazily, since it's stored in the filesystem.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

plugins/markov.py

@@ -38,7 +38,7 @@ def windows(items: Sequence[Any], size: int):
 class Chain:
     def __init__(self, order: int, chance: float, path: Path):
         self.order = order
-        self.reply_chance = chance
+        self.__reply_chance = chance
         self.path = path
         self.__cache = chain_default()
         self.__last_access = 0.0
@@ -47,6 +47,19 @@ class Chain:
     def __touch(self):
         self.__last_access = asyncio.get_running_loop().time()
 
+    @property
+    def reply_chance(self) -> float:
+        self.__load()
+        return self.__reply_chance
+
+    @reply_chance.setter
+    def reply_chance(self, val: float):
+        if not (isinstance(val, float) or isinstance(val, int)):
+            return NotImplemented
+        self.__load()
+        self.__reply_chance = val
+        self.__dirty = True
+
     @property
     def last_access(self) -> float:
         return self.__last_access
@@ -95,7 +108,7 @@ class Chain:
             obj = json.load(fp)
 
         # Load the save object
-        self.reply_chance = obj["reply_chance"]
+        self.__reply_chance = obj["reply_chance"]
         self.__cache = defaultdict(
             chain_inner_default,
             {
@@ -119,7 +132,7 @@ class Chain:
             self.path.parent.mkdir(parents=True, exist_ok=True)
             # Build the save object
             obj = {
-                "reply_chance": self.reply_chance,
+                "reply_chance": self.__reply_chance,
                 "chain": {
                     key: {
                         ("" if word is None else word): weight
@@ -239,6 +252,13 @@ class Markov(Plugin):
                 message = chain.generate()
                 if message:
                     self.send_to(conn, channel, f"{who.nick}: {message}")
+            case ["chance"]:
+                chain = self.get_chain(channel, who.nick)
+                self.send_to(
+                    conn,
+                    channel,
+                    f"{who.nick}: current reply chance is {chain.reply_chance}",
+                )
             case ["chance", chance]:
                 chain = self.get_chain(channel, who.nick)
                 try: