1 files changed, 77 insertions, 0 deletions
diff --git a/apply/state.py b/apply/state.py
new file mode 100644
index 0000000..0bae459
--- /dev/null
+++ b/apply/state.py
@@ -0,0 +1,77 @@
+from pathlib import Path
+import json
+from enum import Enum
+import hashlib
+
+
+def add_or_create(dictio, key, value):
+    if key in dictio:
+        if value not in dictio[key]:
+            dictio[key].append(value)
+    else:
+        dictio[key] = [value]
+
+
+class FileState(Enum):
+    Unused = 1
+    Owned = 2
+    Used = 3
+    links_to_path: Path = Path()
+
+    def can_write(self) -> bool:
+        return self in [FileState.Unused, FileState.Owned]
+
+    def links_to(self) -> str:
+        if self is not FileState.Owned:
+            raise Exception(f"Cannot call location on {self}")
+
+        return self.links_to_path
+
+    @staticmethod
+    def create_owned(links_to: Path) -> "FileState":
+        s = FileState.Owned
+        s.links_to_path = links_to
+        return s
+
+
+class StateFile:
+    links = {}
+    dirs = {}
+    attr_to_save = ["links", "applydir", "dirs"]
+
+    def __init__(self, applydir):
+        # Generate unique string for each possible applydir
+        ustr = hashlib.md5(applydir.encode("utf-8")).hexdigest()[10:]
+        self.applydir = str(applydir)
+
+        self.statefile = Path(f"state_{ustr}.json")
+        if self.statefile.exists():
+            with self.statefile.open("r") as f:
+                self.set_from_dict(json.load(f))
+        else:
+            self.set_from_dict({})
+
+        self.stateclean = True
+
+    def set_from_dict(self, state):
+        self.links = state.get("links", {})
+        self.dirs = state.get("dirs", {})
+        self.applydir = state.get("applydir", self.applydir)
+
+    def save_to_dict(self):
+        all_attr = self.__dict__
+        res = {}
+        for key in self.attr_to_save:
+            res[key] = all_attr[key]
+        return res
+
+    def dump_state(self):
+        with self.statefile.open("w") as f:
+            json.dump(self.save_to_dict(), f)
+
+    def add_dir(self, path: Path, packagename: str):
+        # Add to state
+        add_or_create(self.dirs, str(path), packagename)
+
+    def add_link(self, dest, packagename):
+        self.links[str(dest)] = packagename