Sneak attack, my butt! The codes were broken and FDR knew as much of the attack plan as the Japanese did. He opened Pearl up like a flower for them.
You are straying into Truther Territory, there partner. There was no clear, unambiguous signal saying “attack Pearl Harbor”. Navy intelligence had lost track of the ships in the attack force. Their Morse Code operators had been taken off and placed on islands in the South China Sea, and given dummy traffic to send, since US Huff Duff operators would recognize a particular operator by his “fist”. In retrospect, their are indicators that point to an attack, but hindsight is 20/20. If FDR had known about the attack, he could have done a better job of absorbing it, and would have been in a position to inflict great damage on the Japanese early in the War.
I always felt that the Pearl Harbor attack, as serious as it was, was not daring enough. On December 8, 1941 there was more oil in Hawaii than in Japan. Had the Japanese attacked the oil storage facilities, it is likely that they would never have lost Guadalcanal, and some of the subsequent battles, and the war in the Pacific, would have been lengthened by at least a year. Or more. What if the Japanese had invaded the unprotected beaches of Hawaii a few days after Pearl Harbor, supported by aircraft carriers and naval gunfire, possibly taking the Pearl Harbor out of U.S. hands, and possibly even seizing significant oil reserves?