add storage foundation contracts

domain/chat.py

@@ -0,0 +1,35 @@
+from dataclasses import dataclass
+from datetime import datetime
+from uuid import UUID
+
+HISTORY_FILE_NAME = 'history.md'
+
+
+@dataclass(frozen=True, slots=True)
+class ChatAttachmentName:
+    value: str
+
+    def __post_init__(self) -> None:
+        if not self.value or self.value in {'.', '..'}:
+            raise ValueError('invalid attachment name')
+        if '/' in self.value or '\\' in self.value:
+            raise ValueError('invalid attachment name')
+        if self.value == HISTORY_FILE_NAME:
+            raise ValueError('reserved attachment name')
+
+
+@dataclass(frozen=True, slots=True)
+class Chat:
+    chat_id: UUID
+    workspace_id: UUID
+    created_at: datetime
+
+
+@dataclass(frozen=True, slots=True)
+class ChatFile:
+    file_id: UUID
+    chat_id: UUID
+    name: ChatAttachmentName
+    content_type: str | None
+    size_bytes: int
+    created_at: datetime