Haruhi is talking about "Melt" by Hatsune Miku (music and lyrics by ryo), which starts like
In the morning, I woke up And the first thing that came to my mind Was you I made up my mind and cut my bangs I want to be asked "What's up" [Doushita no] Pink skirt, flower hairpin, Me today is cute. [Kyou no watashi wa kawaii no yo]
...
This...dishevelled, drowsy, giggling Suzumiya
This is hard to figure out... I think this is what's going on? None of these are actually words, they're half-words :PAah... You mean this?Who are you in love with?Ah?*dishevel nonstop!!*Didn't you cut it!What's up, Kyon?Uh?"What's up" with what?Your haaair.You're melting, aren't you!? I said, "Doushita no"! You're like "kyou no watashi wa kawaii", aren't you!?Who!Melt.Haruhi's dialogue doesn't make any sense without watching Melt~ Hatsune Miku.This grown-up Kyon! Like you're in the prime of life, huh?!!So cute! Kyon today is cute, so cute!!meruto [melt]
proper name, -suru
1. To cut your hair due to unrequited love, dress up, and so on, every young woman's conduct; also, to fall in love itself.
2. The wish for this moment to stop.
3. [I can't read this...]
—The wind is blowing.Like hell I know! What do you mean "MELT"!?For who from where are you melting for!!