Support subfolders for Sync locations

[markokocic]

When I set up some directory as a sync location, only org files that are located directly in that directory are read. Org files in subfolders are not considered at all. This makes it unnecessary cumbersome to handle use case with org files inside a folder hierarchy. Also, linking between those org files / notebooks doesn't work, since Orgzly knows nothing about subfolders.

It would be good if Orgzly supported subfolders inside an sync location.

There is a similar ticket reported at #146 which is Git related. This one is more general.

[amberin]

Yeah, see my last comment in #146, but let's keep them separate, since the two repo types have different problems. With Git repos, files in subfolders are loaded but then written to the root folder. I'm not really sure about the Android storage access framework and subfolders... I hope it's possible, but we'll see.

[amberin]

I believe this must be implemented per repo type, so I'm not sure if we should make this issue about the directory repo type (which seems to be the most popular type), or try to keep it general. (I suspect there is nothing wrong in the general code, but rather in the different repo implementations.)

[markokocic]

I think there are two parts of the fix.

• First is making sure Notebook in Orgzly are directory tree aware regarding non-unique names, relative links and so on... This part is general, regardless of the sync type
• Second part is serialisation of such Notebooks and mapping them to different sync types, and there would be a difference between directory, webdav or git

[amberin]

Well, different repo types don't even necessarily use the same storage abstractions. For instance, a "directory" repo with a content:https:// URL does not use the Java.io.File class, whereas git repos do. So the entire "file" or "directory" concepts are different for different repo types. All they have in common are concepts such as Book and Rook (remote book).

[amberin]

The corresponding issue in the original repo is orgzly/orgzly-android#225. It's apparently one of Orgzly's issues that people "like" the most. 😉

I've been trawling the original repo's issues to take stock of the thinking so far, looking for clues on what @nevenz might have explored and/or ruled out. It seems like they saw notebook folder/grouping support in the UI as a goal, or even prerequisite. That is too far out of my comfort zone to take a shot at.

My current hunch is that I might be able to contribute to the following:

1. Add support for some kind of .orgzlyexclude or .orgzlyinclude file (ideally, both options should be possible) in all repo types. This is Support the .orgzlyignore file in all repo types #224.
2. Maybe: Take a shot at Allow selecting multiple notebooks #227, although I have no idea about its potential difficulties.
3. Load files from all subdirectories, with notebook names including the relative path (relative to repo root). This should avoid the most obvious confusion and be usable, if not always pretty. I've looked into it for directory repos, and it doesn't seem too hard. My questions are mostly around how to make the code reusable and testable across repo types.

I think 3) could be a small but worthwhile step forward. It would not entail any UI changes, but updating the documentation would be important, to make users aware of the new "invisible" exclude/include feature of #224.

I believe these additions should probably happen in the order outlined above, since, when we add the last feature, there might be long-time users who risk suddenly loading a big number of org files from subfolders which are currently being ignored. It would then be important that they can easily a) delete multiple unwanted notebooks, and b) add exclude/include rules as necessary.