X-Git-Url: https://plomlompom.com/repos/%7B%7B%20web_path%20%7D%7D/decks/%7B%7Bdeck_id%7D%7D/cards/%7B%7Bcard_id%7D%7D/static/gitweb.css?a=blobdiff_plain;f=plomtask%2Fversioned_attributes.py;h=d3c364942e3d76edf0eb9618df8366866c603709;hb=1a9178b2b7bb66e77f3df01a0c7b2812839637ba;hp=b3442d7df1030b72b2990a21e12ffa12302aa9d1;hpb=5ff672be7e421fbbde8132a66ebb9b734d149a69;p=plomtask

diff --git a/plomtask/versioned_attributes.py b/plomtask/versioned_attributes.py
index b3442d7..d3c3649 100644
--- a/plomtask/versioned_attributes.py
+++ b/plomtask/versioned_attributes.py
@@ -4,6 +4,7 @@ from typing import Any
 from sqlite3 import Row
 from time import sleep
 from plomtask.db import DatabaseConnection
+from plomtask.exceptions import HandledException, BadFormatException
 
 TIMESTAMP_FMT = '%Y-%m-%d %H:%M:%S.%f'
 
@@ -30,6 +31,32 @@ class VersionedAttribute:
             return self.default
         return self.history[self._newest_timestamp]
 
+    def reset_timestamp(self, old_str: str, new_str: str) -> None:
+        """Rename self.history key (timestamp) old to new.
+
+        Chronological sequence of keys must be preserved, i.e. cannot move
+        key before earlier or after later timestamp.
+        """
+        try:
+            new = datetime.strptime(new_str, TIMESTAMP_FMT)
+            old = datetime.strptime(old_str, TIMESTAMP_FMT)
+        except ValueError as exc:
+            raise BadFormatException('Timestamp of illegal format.') from exc
+        timestamps = list(self.history.keys())
+        if old_str not in timestamps:
+            raise HandledException(f'Timestamp {old} not found in history.')
+        sorted_timestamps = sorted([datetime.strptime(t, TIMESTAMP_FMT)
+                                    for t in timestamps])
+        expected_position = sorted_timestamps.index(old)
+        sorted_timestamps.remove(old)
+        sorted_timestamps += [new]
+        sorted_timestamps.sort()
+        if sorted_timestamps.index(new) != expected_position:
+            raise HandledException('Timestamp not respecting chronology.')
+        value = self.history[old_str]
+        del self.history[old_str]
+        self.history[new_str] = value
+
     def set(self, value: str | float) -> None:
         """Add to self.history if and only if not same value as newest one.