I will not explain how useful vim is, if you a developer on the *nix systems, then that is number one tool to tuck into your toolbox.
Now you want to paste huge text into vim and it looks all wacky, and the insert mode is not handling it.. here is what you would do..
Open your vim with
vi filename.ext
then do
:set paste
This will allow your vim to be in the paste mode and you can dump all you have without any problem then change the mode using esc and save it as :w