I don’t know for how long they may have planned it. But I think it’s likely that they would have created some sort of plans for an invasion of Taiwan, based on their statements where they say they don’t rule out force to take over Taiwan. From this article:

Peng Qing’en, a spokesperson for China’s Taiwan Affairs Office, told a regular news conference in Beijing that peaceful “reunification” under the “one country, two systems” model is the fundamental approach to “resolving the Taiwan issue”.

“We are willing to create ample space for peaceful reunification and will spare no effort to pursue this prospect with the utmost sincerity,” he said.

“However, we absolutely will not renounce the use of force and reserve the option to take all necessary measures.”