1 files changed, 101 insertions, 0 deletions
diff --git a/src/training/callbacks/base.py b/src/training/callbacks/base.py
new file mode 100644
index 0000000..d80a1e5
--- /dev/null
+++ b/src/training/callbacks/base.py
@@ -0,0 +1,101 @@
+"""Metaclass for callback functions."""
+
+from abc import ABC
+from typing import Callable, List, Type
+
+
+class Callback(ABC):
+    """Metaclass for callbacks used in training."""
+
+    def on_fit_begin(self) -> None:
+        """Called when fit begins."""
+        pass
+
+    def on_fit_end(self) -> None:
+        """Called when fit ends."""
+        pass
+
+    def on_train_epoch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_train_epoch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_val_epoch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_val_epoch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_train_batch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_train_batch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_val_batch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_val_batch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+
+class CallbackList:
+    """Container for abstracting away callback calls."""
+
+    def __init__(self, callbacks: List[Callable] = None) -> None:
+        """TBC."""
+        self._callbacks = callbacks if callbacks is not None else []
+
+    def append(self, callback: Type[Callback]) -> None:
+        """Append new callback to callback list."""
+        self.callbacks.append(callback)
+
+    def on_fit_begin(self) -> None:
+        """Called when fit begins."""
+        for _ in self._callbacks:
+            pass
+
+    def on_fit_end(self) -> None:
+        """Called when fit ends."""
+        pass
+
+    def on_train_epoch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_train_epoch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_val_epoch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_val_epoch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_train_batch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_train_batch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass
+
+    def on_val_batch_begin(self) -> None:
+        """Called at the beginning of an epoch."""
+        pass
+
+    def on_val_batch_end(self) -> None:
+        """Called at the end of an epoch."""
+        pass