diff --git a/src/file_transfers.py b/src/file_transfers.py
index 9d4995b..486410e 100644
--- a/src/file_transfers.py
+++ b/src/file_transfers.py
@@ -1,2 +1,46 @@
 # TODO: add support of file transfers
 # TODO: add support of avatars
+from toxcore_enums_and_consts import TOX_FILE_KIND
+from os.path import basename, getsize
+
+
+class FileTransfer(object):
+    def __init__(self, path, tox, friend_number):
+        self._path = path
+        self._tox = tox
+        self._friend_number = friend_number
+
+    def set_tox(self, tox):
+        self._tox = tox
+
+
+class SendTransfer(FileTransfer):
+    def __init__(self, path, tox, friend_number):
+        super(self.__class__, self).__init__(path, tox, friend_number)
+        self._file_number = tox.file_send(friend_number, TOX_FILE_KIND['DATA'], getsize(path), None, basename(path))
+
+    def get_file_number(self):
+        return self._file_number
+
+    def send_chunk(self, position, size):
+        with open(self._path) as f:
+            f.seek(position)
+            data = f.read(size)
+        return self._tox.file_send_chunk(self._friend_number, self._file_number, position, data)
+
+
+class ReceiveTransfer(FileTransfer):
+    def __init__(self, path, tox, friend_number):
+        super(self.__class__, self).__init__(path, tox, friend_number)
+
+    def write_chunk(self, position, data):
+        size = getsize(self._path)
+        if size < position + len(data):
+            with open(self._path, 'w') as f:
+                f.write('\0' * (position + len(data) - size))
+                f.seek(position)
+                f.write(data)
+        else:
+            with open(self._path, 'w') as f:
+                f.seek(position)
+                f.write(data)