Move attachment after upload with 3.5 media manager

These might help:
https://codex.www.ads-software.com/Function_Reference/wp_handle_upload
https://wordpress.stackexchange.com/questions/67763/how-to-change-upload-directory-in-wp-handle-upload
https://codex.www.ads-software.com/Function_Reference/wp_upload_bits
https://codex.www.ads-software.com/Function_Reference/wp_update_attachment_metadata
https://codex.www.ads-software.com/Function_Reference/wp_generate_attachment_metadata
https://codex.www.ads-software.com/Function_Reference/wp_insert_attachment

Thanks! A lot of stuff to go through! I guess I would use PHP copy function to make a copy of the original file uploaded, set a filter on the upload_dir, call wp_generate_attachment_metadata and then call wp_update_attachment_metadata and then remove the filter on upload_dir again.

Will setting the filter on upload_dir be enough to make sure the file is in the uploads folder, as per requirement below?

$file
(string) (required) Location of the file on the server. Use absolute path and not the URI of the file. The file MUST be on the uploads directory. See wp_upload_dir()
Default: None

Why not change the upload directory? Or do attachments have to be in two directories?
https://codex.www.ads-software.com/Editing_wp-config.php#Moving_uploads_folder

No, only one directory necessary.
ok, so maybe I misunderstood the requirement.

Let’s say I upload into uploads/tmp, i can then move files to let’s say:

uploads/%username%/%post_type%/%title% as that would still be in the “uploads” folder.
Correct?

I also thought about changing the uploads directory with “custom upload dir”plugin, but in my scenario (custom front end media uploader and post creation) I am creating attachments without knowing the post title or post_id yet. Once the post is created I obviously know the post title (which is part of the upload directory path) and then have to update all the files and attach the images to the post.