Ahmadinejad has already threatened to cancel the election before it happens. As part of his non-election, which he may try to cancel, he has kicked off what he declares is a "Viva Spring"
The good news is that Ahmadinejad won't be running in this election. The bad news is that Ahmadinejad intends to keep on running things through a handpicked puppet president. The good news is that all the infighting is tearing the Iranian regime apart.
Ahmadinejad has already threatened to cancel the election before it happens if his puppet, Esfandiari Rahim Mashaei, isn't approved as a presidential candidate. It's not clear if he will actually be allowed to do that, but political disputes in Iran get settled by whoever has custody of the Revolutionary Guard.
As part of his non-election, which he may try to cancel, Ahmadinejad has kicked off what he declares is a "Viva Spring". That apparently consists of him releasing tapes of his opponents engaging in corruption. His opponents have been releasing tapes and videos of his cronies engaging in corruption. The tape releases are meant to restore Ahmadinejad's image as a reformer, but they are infuriating the Iranian establishment, such as it is.
Ayatollah Ali Khamenei, who in theory runs the country, has blasted Ahmadinejad for his antics, but can't remove him because he declared that the rigged election last time around was Allah's work. And you can't talk back to Allah when he steals an election. The ridiculous side of this is that the same establishment which brutally murdered and tortured its own people to protect Ahmadinejad's stolen election are desperately trying to get rid of him.
Khamenei is calling for unity in the face of the Great Satan, the Medium Satan and the Little Satan, but no one is paying attention to him. The actual outcome of the election probably rests with Revolutionary Guard generals and may come down to a question of which side can offer the biggest bribes.
Meanwhile Ali Fallahian is the establishment's likely next choice to be the President of Iran. Ali Fallahian makes Ahmadinejad look like a sane and reasonable moderate. Ali Fallahian specialized in terrorism and is wanted by Interpol for the bombing a Jewish community center in Argentina. He's wanted by a German court for restaurant assassinations and by Switzerland for a murder over there.
Fallahian will be running on a platform of turning Iran into an "Advanced Islamic Country" and improving relations with the United States.