Can a landlord keep your deposit when they do a walkthrough before you even move out?

We were locked out of our rental about 10 days before our lease was up. The landlord did a walkthrough and charged us for items that were wrong. Dirty floors, bathrooms, etc. But we hadn't even finished moving our things out yet. Our lease wasn't up til the end of the month. Is this legal and how long do we have to take action to sue them for our deposit back? We thought they would sue us because they wanted more then our deposit, but they haven't yet. Is this because they know that they messed up??