>If god is almighty and sees the future, how come he didn't think of that on damn tree in the middle of paradise?
He made that tree. So, I'd say He thought of it. He made it for the precise purpose of giving mankind the ability to choose. If we didn't have the ability ability to choose God, then our serving Him would be pointless, since we'd essentially be mindless drones. God wanted people to have the ability to love Him of their own free will.
>If god is perfect, how come he failed at making man perfect too?
Adam and Eve were perfect. Then they chose not to be perfect.
>If god is almighty and the enemy of Satan, how come he doesn't just kill Satan?
Because Satan still serves a purpose. I'm not entirely sure of all of it, but the main purpose seems to be to provide an obvious choice for us. God or Satan, who do you want to serve?
>If god is good and almighty how come there are so much innocents suffering in the world? Probable answer: because he tests people. But if he sees the future it's needless.
Testing is part of it. But testing is for our benefit, not His. Like you said, He knows the future, so He already knows what we will do.
The larger part is that humans can make choices, see my first answer. And thus, humans make choices that hurt others. The airplane mechanic who missed the problem that cause random flight to crash made the choice not to be thorough. The criminal chose to rob that bank and shoot the teller.
So, bad things happen to good people because good and bad people make bad choices.
As for natural disasters, they happen because humanities choices effect more than just humanity. The entire world was perfect before Adam sinned. When he sinned, the entire world broke.