Why Did Hamas Provoke a War?

The current battles between Israel and Hamas were provoked by Hamas. Why? It is a very big gamble for Hamas, and the size of the gamble is the measure of Hamas’s desperation. For so far, Hamas has not done much damage to Israel. Meanwhile Israel targets Hamas’s missiles and especially its missile launchers, headquarters, arsenals and warehouses, and leaders. There is not much Hamas can call a victory except proving the range of its rockets.