I don't endorse Iran. I just don't fall for obvious lies and deceptions. I think Iran is backwards and intolerant. But that doesn't mean I believe every negative thing said about them by their enemies or representatives of oil companies.
For example, describing this facility as a secret is an obvious whopper. If its a secret then how did the news know about it? The reason why is that this facility was revealed 3 years ago and became a known facility. Six months later, Iran started installing centrifuges. Iran's "secret" facilities even offer guided tours:
PressTV - Mongolian president visits Natanz uranium enrichment plant
I have read the IAEA reports about Iran and they have nothing incriminating. Not only don't they have a smoking gun, they don't even have smoke, a gun or bullets. Yet you believe they are guilty???
Iran experimented with enrichment, before they signed the NPT. But they declared their activities when they signed the NPT. Iran didn't reveal the existence of some of their facilities until 180 days before they were ready to start installing equipment, because they don't have to. An empty cave isn't a nuclear facility until equipment is installed. The IAEA inspected these sites, confirmed they were empty, monitored the installation process, set up cameras and perform regular inspections. A stolen laptop allegedly from an Iranian scientist had a nuclear weapon simulator program. A nuclear weapon simulation program requires the processing power of a supercomputer to be practical. A laptop might be able to complete the necessary calculations after a few decades of processing and it would have to be based on measurements taken from weapons grade uranium, which Iran doesn't possess.
As far as anyone knows Iran has not exceeded the 20% HEU limit required to build nuclear weapons. They need 20% HEU for their medical isotope reactor, because they can't import medical isotopes. Nuclear weapon components must be made from greater than 20% HEU.
The problem with your scenario that Iran already has nuclear weapons is that in order for the design to be useful, it has to be tested. Testing a nuke without anyone noticing is impossible. The smallest nuke is the equivalent of a 4.5 magnitude earthquake. Every seismic monitoring facility in the world would record that event. Likely Turkey, Russia, India and China have seismic stations located close enough to Iran to notice any Iranian nuclear test.
FYI: A nuke's seismic signature is completely different than an earthquake. Earthquakes occur deep underground, build up in intensity and dissipate, usually with aftershocks. Nuclear weapons are tested near the surface, release their energy at once and no aftershocks. They are as different from each other as an elephant is from a blue whale.
Yet you believe all this BS about Iran's nuclear weapons program, despite a lack of any supporting evidence. Who is living in a fantasy world again????