creating global context and refactoring tmp_dir logic

src/auto_archiver/core/context.py

@@ -0,0 +1,38 @@
+
+class ArchivingContext:
+    """
+    Singleton context class.
+    ArchivingContext._get_instance() to retrieve it if needed
+    otherwise just 
+    ArchivingContext.set(key, value)
+    and 
+    ArchivingContext.get(key, default)
+    """
+    _instance = None
+
+    def __init__(self):
+        self.configs = {}
+
+    @staticmethod
+    def get_instance():
+        if ArchivingContext._instance is None:
+            ArchivingContext._instance = ArchivingContext()
+        return ArchivingContext._instance
+
+    @staticmethod
+    def set(key, value):
+        ArchivingContext.get_instance().configs[key] = value
+
+    @staticmethod
+    def get(key: str, default=None):
+        return ArchivingContext.get_instance().configs.get(key, default)
+
+    # ---- custom getters/setters for widely used context values
+
+    @staticmethod
+    def set_tmp_dir(tmp_dir: str):
+        ArchivingContext.get_instance().configs["tmp_dir"] = tmp_dir
+
+    @staticmethod
+    def get_tmp_dir() -> str:
+        return ArchivingContext.get_instance().configs.get("tmp_dir")