ADD paths module

To automate the fetching of the state file in a safe, atomic way.

rewind/paths.py

@@ -0,0 +1,20 @@
+from pathlib import Path
+import os, json
+
+APP_NAME = "rewind"
+
+def state_dir() -> Path:
+    base = os.path.expanduser("~/.local/share")
+    path = Path(base) / APP_NAME
+    path.mkdir(parents=True, exist_ok=True)
+    return path
+
+def get_state_file_path() -> Path:
+    return state_dir() / "state.json"
+
+def get_state_file() -> dict:
+    path = get_state_file_path()
+    if not path.exists():
+        return {"files": []}
+    with path.open() as f:
+        return json.load(f)