How far is Iran from the "weapon"?
Iran has 300 kg of Uranium where 3% is U235
For the weapon it needs at least 25 kg of U235 which must be 90% purified.
With that calculation it has 10 kg of U235. They have to increase the stockpile 10 times the current limit and then purify it to 90%.
For purification they will need centrifuging machines, which they have to run for years. Purifying the uranium in stages until its 90% pure.
Iran is at least 3 years away from getting the bomb, IF they start to work on it at full speed right now.
The case is : they aren't working on it, and still don't have the intent to build one.
So I would say the bomb is very far.