Equation editor undo

src/bedit_gui/commands/equation_text_command.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+from PySide6.QtGui import QUndoCommand
+
+from bedit_core.models import Component, EquationImplementation
+
+
+class ChangeEquationTextCommand(QUndoCommand):
+    COMMAND_ID = 1001
+
+    def __init__(self, document: object, component: Component, section: str, text: list[str], edit_id: int) -> None:
+        super().__init__(self._command_text(section))
+        implementation = component.implementation
+        if not isinstance(implementation, EquationImplementation):
+            raise TypeError("equation text can only be changed on an equation component")
+
+        self.document = document
+        self.component = component
+        self.section = section
+        self.old_text = list(getattr(implementation, section))
+        self.new_text = list(text)
+        self.edit_id = edit_id
+
+    def id(self) -> int:
+        return self.COMMAND_ID
+
+    def mergeWith(self, other: QUndoCommand) -> bool:
+        if not isinstance(other, ChangeEquationTextCommand):
+            return False
+        if other.component is not self.component or other.section != self.section or other.edit_id != self.edit_id:
+            return False
+        self.new_text = list(other.new_text)
+        return True
+
+    def redo(self) -> None:
+        self._set_text(self.new_text)
+
+    def undo(self) -> None:
+        self._set_text(self.old_text)
+
+    def _set_text(self, text: list[str]) -> None:
+        implementation = self.component.implementation
+        assert isinstance(implementation, EquationImplementation)
+        setattr(implementation, self.section, list(text))
+        self.document.equation_text_changed.emit(self.component, self.section)
+
+    @staticmethod
+    def _command_text(section: str) -> str:
+        return {
+            "declarations": "Edit declarations",
+            "initial_equations": "Edit initial equations",
+            "equations": "Edit equations",
+        }[section]