Ask HN: What's a good lib for inputting text that also supports file uploads?

What I'm really looking for is something nearly identical to GitHub's issue comment box (without the preview). It's where you can type markdown, but the key feature is how well the file uploader is integrated. It supports drag / drop, selecting it from a dialog or even pasting, but the killer feature is how it injects the markdown syntax straight into the textarea with the absolute URL of the file that was uploaded. What's a good lightweight open source library to handle that? I'm coming up empty with Google. It's sounding like I'll have to roll my own with a bunch of separate libraries, but I figured I'd ask here before doing that. Thanks.