Loki
Must have rained while you were away. Lee's advice is good. You have to dry out the car.
How did the water get in? Does the left passenger window work? I take it the buzzing comes when you try to move the driver's seat? Also the door switches. Sounds like the switches are wet, and you are losing power to earth at the switch or power connection.
Leave the doors wide open to let the water evapourate. Turn on the engine and the heater full blast to help it. Stay with the car while doing this, don't give thieves an opportunity to drive away in your pride and joy, just because you have a leak.
Your sunroof [see title
] has a drain channel piped down to the left rear wheel arch to let water out at wheel level. There is a vent pipe just below the power antenna for it. I suspect this pipe blocked up somewhere, and the water around your sunroof channel got into your interior. If this is correct, you must fix this. Take off the panel in the trunk, left side, for accessing the rear bulbs. Remove some rubber trim, and you can see how to slide off the left trim panel in the trunk, it is pretty easy. You should now see where the sunroof drain connects to the outlet behind and below the antenna, connected to the outer metal of the wheel-arch. You might try disconnecting this drain, pour some water on the sunroof, see if it is making it's way out the drain. If it's not [as I suspect] the drain hole at your sunroof channel is blocked, and you need to free it up.
Best of luck with it.
Joe
PS If the sunroof won't open, and you can't get to the drainage outlet in the channel to check for blockage, consider going to a sunroof specialist to get it powered up and unblocked. They probably get this all the time, and would be quicker getting it sorted than you would.