Implement undo

tests/test_cli.py

@@ -11,6 +11,7 @@
 import click
 import hypothesis.strategies as st
 import pytest
+import pytz
 from dateutil.tz import tzlocal
 from freezegun import freeze_time
 from hypothesis import given
@@ -749,6 +750,55 @@ def test_done_recurring(runner, todo_factory, todos):
     assert todo.rrule == rrule
 
 
+def test_undo(runner, todo_factory, todos):
+    completed_at = datetime.datetime.now(tz=pytz.UTC)
+    percentage = 100
+    todo = todo_factory(completed_at=completed_at, percent_complete=percentage)
+
+    result = runner.invoke(cli, ["undo", "1"])
+    assert not result.exception
+
+    todo = next(todos(status="ANY"))
+    assert todo.percent_complete == 0
+    assert todo.is_completed is False
+    assert not todo.rrule
+
+
+@pytest.mark.xfail(reason="Not implemented")
+def test_undo_recurring(runner, default_database, todo_factory, todos):
+    rrule = "FREQ=DAILY;UNTIL=20990315T020000Z"
+    recurred = todo_factory(id=2, rrule=rrule)
+
+    completed_at = datetime.datetime.now(tz=pytz.UTC)
+    percentage = 100
+    related = [recurred]
+    original = todo_factory(
+        id=1,
+        rrule=None,
+        completed_at=completed_at,
+        percent_complete=percentage,
+        related=related,
+    )
+    assert original.related
+
+    default_database.update_cache()
+    result = runner.invoke(cli, ["undo", "1"])
+    assert not result.exception
+
+    default_database.update_cache()
+
+    todos = todos(status="ANY")
+    todo = next(todos)
+
+    assert todo.percent_complete == 0
+    assert todo.is_completed is False
+    assert not todo.related
+    assert todo.rrule == rrule
+
+    todo = next(todos)
+    assert not todo
+
+
 def test_cancel(runner, todo_factory, todos):
     todo = todo_factory()
 

todoman/cli.py

@@ -470,6 +470,30 @@ def done(ctx, todos):
         click.echo(ctx.formatter.detailed(todo))
 
 
+@cli.command()
+@pass_ctx
+@click.argument(
+    "todos",
+    nargs=-1,
+    required=True,
+    type=click.IntRange(0),
+    callback=_validate_todos,
+)
+@catch_errors
+def undo(ctx, todos):
+    """Undo one or more tasks."""
+    toremove = []
+    for todo in todos:
+        removable = todo.undo()
+        if removable:
+            toremove.append(removable)
+        ctx.db.save(todo)
+        click.echo(ctx.formatter.detailed(todo))
+
+    for todo in toremove:
+        ctx.db.delete(todo)
+
+
 @cli.command()
 @pass_ctx
 @click.argument(

todoman/model.py

@@ -250,6 +250,27 @@ def complete(self) -> None:
         self.percent_complete = 100
         self.status = "COMPLETED"
 
+    def undo(self) -> Todo | None:
+        """Immediately restores this todo.
+
+        Marks it as needs action, resets the percentage to 0 and deletes the
+        completed_at datetime.
+        If this todo belongs to a series, the one created at completion will
+        be deleted.
+
+        Returns the todo that should be deleted.
+        """
+        recurred = None
+        if self.is_recurring and self.related:
+            recurred = self.related.pop()
+            self.rrule = recurred.rrule
+
+        self.completed_at = None
+        self.percent_complete = 0
+        self.status = "NEEDS-ACTION"
+
+        return recurred
+
     @cached_property
     def path(self) -> str:
         if not self.list: