Refactor Sidepane logic

[HoussemNasri]

Refactoring goals:

• Remove all view references fromSidePaneComponent
• Instead of having an instance of SidePane in SidePaneComponent for updating the view, we should use binding
• Remove unnecessary abstraction in SidePane like (separating components and visibleComponents)
• Maybe refactor SidePaneComponent into view and ViewModel
• and finally, fix View menu for sidebar option can be out of sync with sidebar state  #8115

Edit: I ended up redesigning the whole component so don't take the above goals as a grant

Added classes

• SidePaneContainerView / SidePaneContainerViewModel: This is the replacement for SidePane, it has almost the same actions/methods (show, hide, toggle, moveUp, moveDown) but in private because they are not used from the outside, it has one public method sidePaneVisibleProperty(sidePaneType) in the view, it returns the visibility property for sidePaneType, it's public because it's the only property used from the outside (check menu).
• SidePaneHeaderView: This class represent the header view that used to be created using SidePaneComponent#getHeader, this class controls the position/visibility of a SidePaneView using actions received in the constructor (moveUpCommand, moveDownCommand, closeCommand).
• SidePaneView: This is a replacement for SidePaneComponent, it glues together the content of the pane with the header.
• GroupsSidePaneView: This is a specialized implementation of SidePaneView with 2 differences, an afterOpening method and a special header GroupsSidePaneHeaderView because groups pane uses an extra button for toggling intersection union, I didn't put afterOpening in the base implementation because the other sidepanes (webSearch and OpenOffice) don't use it.
• GroupsSidePaneHeaderView: This is a specialized implementation of SidePaneHeaderView with an extra button for toggling intersection union, it handles it internally.
• WebSearchPaneView: I just copy-pasted WebSearchPane#createContentPane into its own class.

Notes

• The visibility property of side panes is updated when visiblePanes list changes in SidePaneContainerViewModel.
• I gave up on afterOpening and beforeClosing methods in SidePaneComponent because they are only adding and removing panes to/from preferencesService.getSidePanePreferences().visiblePanes(), preferences visible panes are now updated from SidePaneContainerViewModel in show() and hide(), the only side pane that does something beside that, is GroupsSidePaneView that's why we added afterOpening to it.
• SidePaneType has the title, icon, and action of the side pane so it can be considered a model in the new design.

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository

Desktop.2021.10.31.-.23.42.59.02.mp4

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[calixtus]

Great Idea, already looked into the issue about the view menu, but had not yet found a working solution. The enum of components seems to be a bit overcomplicated and inflexible too...

[HoussemNasri]

Codacy is complaining and saying that there is a missing enum branch in the switch statement which is not true, can someone tell me what's wrong?

[calixtus]

Forget about codacy!

[tobiasdiez]

Thanks a lot for you work! This is sooooo much better already.

I have a couple of further suggestions mainly around the main direction of information flow (using the StateManager class) and using javafx bindings.

[calixtus]

Is this PR ready for final review now?

[calixtus]

Hi @HoussemNasri : since this PR was a bit stalled, I took the liberty to work a bit on it. After all the great work you already did, I just refactored SidePane and SidePaneViewModel a bit to better implement the MVVM-Pattern. Also I reduced the code duplication with the visible properties for the menu. Works with Bindings and only one source of truth now.

The second thing I tried to work on was the bug about the not-closing sidepane, when every component is closed. This should work now (I moved the listener from the visible property to the children list of the sidepane), but the issue mentioned by @Siedlerchr (#8082 (comment)) still remains, which means that the initial width of the sidepane if open on startup is not right. Need to investigate some more.

[calixtus]

Fixes #8115
Fixes #8082

[calixtus]

This should work now and close two bugs.
Big thanks to @HoussemNasri for refactoring the sidepane logic, which is way more clearer and understandable now.
Sorry it took so long to work on it, I had too much work in the last weeks. Should be better now.

[HoussemNasri]

Thank you @calixtus! I'm glad I got to work with you and other brilliant developers on this project, learning tons about making software according to best practices. I feel like I have more and better skills than ever now, too! I'll definitely be getting involved more as time goes on; both with Jabref and in the open-source community - so thank you again!

[Siedlerchr]

@tobiasdiez Do you have any issues left? Otherwise I would like to merge this so we can get this in our next release asap

[tobiasdiez]

I don't really have time to look at this in detail. If you think its fine, please go ahead and merge it.