feat: add block serializer

src/pyzantium/block.py

@@ -1,10 +1,63 @@
+from abc import ABC, abstractmethod
 from datetime import datetime
+from typing import Generator
 
 
 class Block:
+    """
+    Programatical representation of a block in a chain
+
+    This class is just and abstraction of block. just holds neccesary
+    information and data about a block. Instanteniation of this class doesn't
+    mean that this block is part of a chain, in fact it is a data class.
+    """
+
     def __init__(self) -> None:
-        self._hash = bytes()
-        self._prev_hash = bytes()
-        self._nonce = None
-        self._timestamp = None
+        self._hash: bytes = bytes()
+        self._prev_hash: bytes = bytes()
+        self._nonce: int = None
+        self._timestamp: datetime = None
         self._data = None
+
+    def __eq__(self, other: object) -> bool:
+        # comparing hashes is enough
+        if isinstance(other, Block):
+            return self._hash == other._hash
+        else:
+            raise TypeError(
+                "Object of type {} is not a Block or subclass of it".format(
+                    other.__class__
+                )
+            )
+
+
+class BlockSerializer(ABC):
+    """
+    An abstract base class to serialize a block to variuse types
+
+    Using data stored in a block involves converting it to some specific
+    bytes data. Specialy when it is needed to hash it. ``Block`` class is just a
+    data holder and to produce flattened raw byte, an other class is needed to
+    convert it.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+
+    @abstractmethod
+    def to_storing(self) -> Generator[bytes, None, None]:
+        """
+        Converts the given block to a format ready to store in the storage
+
+        :rtype Generator:
+        """
+        ...
+
+    @abstractmethod
+    def to_finilizing(self) -> Generator[bytes, None, None]:
+        """
+        Converts the given block to a format to use in finalizing operation
+
+        :rtype Generator:
+        """
+        ...