https://dl.dropboxusercontent.com/u/...ate%202912.avi
This is a really rare interview with Stargare team at an event of ASCAP in 2012. The talk about how Fireword was produced starts at 50:00
According to this video, before Rihanna heard OG, Stargate played the demo of the song for Katy Perry. Then Katy desperately wanted to record that song.
Unfortunately, OG was written for Rihanna so Rihanna had to listen to the song first. If Rihanna hadn't want it, Katy would have chose it as the first single.
Two weeks later, Rihanna chose it as the first single. After that, she wanted to work with Stargate for the first time and Firework was composed for Katy.
Image the meltdown if Rihanna had rejected it and given it to Katy, Katy might have 6 no.1s from 1 album.