Saudi Arabia supports Daesh, primarily because Daesh are fighting against Assad who Iran supports. I think the Saudis also support the other opposition groups, basically if they're shooting at Assads forces then the Saudis will give them money to continue doing so. Turkey is in much the same boat, it's not so much to do with radical Islam but regional geopolitics, with Turkey wanting to keep Syria down, and Saudi Arabia wanting to block Iran from becoming a major regional player.
The west sticking our hands into this, it's tricky and must be done very carefully or it'll be akin to putting our hands into a blender.