move data of Document Library from on Site to sub site in Office 365 Site

Question

I have a Task to move data of Document Library from on Site to sub site, below is the situation, Using office 365 Need to migrate a library and its folder to a sub site where folders would be treated as libraries in that sub site The size of the library is 3.29 GB. I have to write a custom code for this. The various details of the documents etc must be restored like the modification date, version history etc.