PROGRESS

I developed the app in my local environment (Apache 2.2, PHP 5.4.5, Windows 7 x64).

I don't have much experience with Object Oriented Programming. I couldn't work out what kind of architecture is needed to utilise FileInterface and FileSystemInterface.
I've defined some very simple classes and tried to use them but most of my code is still procedural.
I've ended up duplicating code because I don't understand the objects, and I wasted too much time trying to work it out.

The only parts I managed to get to a working state are the displaying of current files and deleting files (but it's not at all secure).

Generally, I try to adhere to the PHP FIG PSR coding standards but I couldn't get the namespacing or class autoloading to work.
At first I used separate files for my own classes and placed them into a vendor namespace directory.
However I could only get autoloading to work with FileInterface, so instead I wrote my classes in the same files as the interfaces.

As I was only dealing with a single folder of files, I simply used scandir() to read them all.

I made some assumptions about the task in order to simplify it.
I assumed that this file manager is for basic management of files in a single folder, by a single trusted user.
I wasn't sure if I was meant to create a proper login system so I didn't do any session stuff.

For a simple file manager, a database didn't seem necessary so I chose to work with flat files.
However, I can see how using a database as the storage engine could be simpler, regarding permissions/concurrency/operating systems.
It would also be safer to reference files by id numbers rather than filenames.

I setup the application in a non-OOP MVC style, with a basic front controller.
I've used an old, basic Template class (that I've modified). I like it because it keeps markup and logic 100% separate.
However it has no caching so a modern template system like Twig would be better.

This app needs much more sanitising and validation of filenames and checking/setting permissions.
Depending on the exact requirements of the application/intended audience, I would generally want to disallow file names that:
 - consist only of fullstops
 - begin or end with a fullstop/space/null
 - contain characters other than a-z, 0-9, hypens, underscores or fullstops
 - are longer than 30 characters

I used the Bootstrap theme and a very basic page header.
In previous projects I've used jQuery UI dialogs to good effect but Bootstrap is incompatible with jQuery UI.
I tried using Bootstrap modals instead, but unfortunately they don't support multiple modals.

I wrote some Javascript to render and sort the table of files. Normally I would add paging/filtering etc but left those bits out.
The way that I have implemented Javascript is not the best way, it would be better to use something like Backbone/Angular.

Regarding version control... Normally I try to do "atomic" commits, where each commit is a single change/feature/addition etc. but as I was confused by the OOP I wanted to experiment first.
I've taken too long and it's not even fully functional, so I'll commit everything in one go.