Add dirty flag to markov chains

If something is changed in a markov chain it gets flagged as dirty,
which is used to determine whether the chain should be saved.

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

plugins/markov.py

@@ -40,6 +40,7 @@ class Chain:
         self.path = path
         self.__cache = chain_default()
         self.__last_access = 0.0
+        self.__dirty = False
 
     @property
     def last_access(self) -> float:
@@ -54,6 +55,7 @@ class Chain:
             head = fragment[0:-1]
             tail = fragment[-1]
             self.__cache[" ".join(head)][tail] += 1
+        self.__dirty = True
 
     def get(self, key: str) -> dict[str | None, int]:
         self.__last_access = asyncio.get_running_loop().time()
@@ -73,6 +75,7 @@ class Chain:
             # Attempt the cache before writing to it
             self.__load()
         self.__cache[key] = defaultdict(int, value)
+        self.__dirty = True
 
     def __load(self):
         self.__last_access = asyncio.get_running_loop().time()
@@ -95,31 +98,33 @@ class Chain:
                     for key, value in json.load(fp).items()
                 },
             )
+        self.__dirty = False
 
     def save(self, retain: bool = True):
         if not self.__cache:
             return
-        if retain:
+        if self.__dirty:
             log.info("Saving markov chain to %s", self.path)
-        else:
-            log.info("Saving markov chain to %s (not retaining)", self.path)
-        self.path.parent.mkdir(parents=True, exist_ok=True)
-        with open(self.path, "w") as fp:
-            json.dump(
-                {
-                    key: {
-                        ("" if word is None else word): weight
-                        for word, weight in value.items()
-                    }
-                    for key, value in self.__cache.items()
-                },
-                fp,
-            )
+            self.path.parent.mkdir(parents=True, exist_ok=True)
+            with open(self.path, "w") as fp:
+                json.dump(
+                    {
+                        key: {
+                            ("" if word is None else word): weight
+                            for word, weight in value.items()
+                        }
+                        for key, value in self.__cache.items()
+                    },
+                    fp,
+                )
+            self.__dirty = False
         if not retain:
+            log.debug("Pruning markov chain %s from memory", self.path)
             self.clear_cache()
 
     def clear_cache(self):
         self.__cache.clear()
+        self.__dirty = False
 
     def __bool__(self) -> bool:
         return self.path.exists() or bool(self.__cache)