It's an in-progress fic called Silver Moonflower and the Sorcerer's Stone. (Yes, the writer's going by the American version of the books.) Its titular character is a Mary Sue that's crushing on Harry Potter. Also, she can sense emotions and see everything and invents spells. In first year. *sigh*

Here's the link to Chapter 1: https://www.fanfiction.net/s/12383391/1/Silver-Moonflower-and-the-Sorcerer-s-Stone

And here's the link to Chapter 2: https://www.fanfiction.net/s/12383391/2/Silver-Moonflower-and-the-Sorcerer-s-Stone