What if Mao Zedong had lived to see the 1979 Chinese invasion of Vietnam?

What exactly did Pol Pot have in mind, in committing genocide against his own people, and in provoking much larger and more powerful Vietnam to invade his country, and drive him from power? Was he merely insane, or was there any conceivable rationale to his apparently self-destructive actions? I think there might have been. Suppose that Mao Zedong, undoubtedly Pol Pot's idol and role model, had just lived a few more years. Clearly, the pragmatic and non-ideological Deng Xiaoping, was not going to risk massive Chinese casualties and a possible war with the Soviet Union in a long, full scale war of conquest against Vietnam, with the possibility of an endless guerrilla war of the type that had just nearly brought the U.S. to its knees. However, Mao Zedong might well have been another kettle of fish. While we can carp at Pol Pot's two million killed, we must remember that four million Vietnamese had just died in America's pointless adventure in Vietnam, almost entirely as a direct result of America's actions there. Indeed, America has more recently successfully eliminated the two million Christians in Iraq, in an effort at "nation building" of a largely Shiite Iraq. Genocide is, unfortunately, a rather common element of "nation building". Having "rebuilt" Cambodia through his genocide, Pol Pot was undoubtedly aware that Vietnam would seek to control him through invasion. However, if Mao Zedong had still been alive, might he not have seen this event as a golden opportunity to retake much or all of Indochina as once more a part of China, as it has been in the past? And, might this not have been exactly what Pol Pot, ultimately, had in mind? Mao Zedong was not known for backing down. Once he had invaded Vietnam, wouldn't he have, almost certainly, finished the job?