Who did Johnny Carson want to replace him when he retired from the Tonight Show, David Letterman or Jay Leno ?

Johnny was prepping Letterman to replace him by having him guest host so much. THen NBC chose Leno. The Late Shift movie is NOT accurate. And David was crushed. He asked Johnny what he'd do if he were in his shoes, and Johnny said "I'd walk". So David left NBC and CBS grabbed him and bought the Ed Sullivan theatre for his show. Johnny only appeared on TV after his retirement by doing walk-ons and short jokes for David. He never appeared with Leno. And at one point Carson would send jokes he had written to David. One night David did his whole monologue using Johnny's jokes. He said this later. He and Johnny were very close.