mod works entirely server side using polymer with no resource pack required
also works in singleplayer
the fireball can be crafted with 4 wind charges and 1 fire charge!
there's also a configuration file in config/fireball.json and the default config is:
{
"fireballCooldownTicks": 5,
"fireballDivergence": 0.0,
"fireballSpeed": 2.0,
"fireballExplosionPower": 2
}