Mirror up, shutter closed. New batteries, light meter works.

SOURCE: light meter problem and blank developed film

I'm afraid you have a somewhat serious problem. There is a tungsten cable that runs from the speed dial to the rewind side if the camera. This cable sets the brushes for the electrical contacts the are under the rewind assembly. Adjusting speeds or ASA changes the position of the contacts.

It is very likely that the cable has broken and needs replaced. Canon no longer supports these nor do they have parts

SOURCE: Hi I have a canon ae-1 but the mirror stays

The mirror has most likely locked up due to the battery being dead. Replace the battery and the mirror should drop down and the shutter will work again.

SOURCE: Advance lever is stuck. I

Like all AE-1's and related models, your camera is gumming up inside as the internal lubricant films are at least 25 years old and are largely dried-out.

The fix is to get the camera to a repair specialist for a CLA service (Clean, Lubricate, Adjust). As a one-off extra cost also get the foam light seals and foam mirror buffer replaced as they'll either be absent by now or will still be turning to a sticky goo. Modern foam is is different material and is will not decay like the old stuff.

A CLA and foam replacement definitely costs more than the residual value of the camera, but they're solidly built and have plenty of cheap high quality lenses so can still achieve results which compare well to even the best modern pro dSLR's. Get the work done and your camera will probably last until 35mm film ceases to be available. Your camera will also withstand conditions which you'd never dare risk a dSLR in.