"""
Ctrl+Z / Ctrl+Y undo/redo for CTkEntry widgets.
tk.Entry has no built-in undo, so we track history manually.
"""


def enable_undo(ctk_entry):
    """Add Ctrl+Z undo and Ctrl+Y redo to a CTkEntry widget."""
    entry = ctk_entry._entry
    history = [entry.get()]
    redo_stack = []
    _recording = [True]

    def _snapshot(*_args):
        if not _recording[0]:
            return
        val = entry.get()
        if not history or history[-1] != val:
            history.append(val)
            redo_stack.clear()
            if len(history) > 200:
                del history[:100]

    def _undo(event):
        if len(history) > 1:
            redo_stack.append(history.pop())
            _recording[0] = False
            entry.delete(0, "end")
            entry.insert(0, history[-1])
            _recording[0] = True
        elif history:
            redo_stack.append(history.pop())
            _recording[0] = False
            entry.delete(0, "end")
            _recording[0] = True
        return "break"

    def _redo(event):
        if redo_stack:
            val = redo_stack.pop()
            history.append(val)
            _recording[0] = False
            entry.delete(0, "end")
            entry.insert(0, val)
            _recording[0] = True
        return "break"

    entry.bind("<KeyRelease>", _snapshot, add="+")
    entry.bind("<Control-z>", _undo)
    entry.bind("<Control-y>", _redo)