Add previous/next entry navigation to diary pages #6901

[Sinty026]

Description

Addresses #6901 — diary pages currently have no previous/next navigation, requiring users to return to the diary overview to move between entries.

This PR adds a navigation bar above the comments section with Previous Entry and Next Entry links. The links are conditionally rendered. If there is no previous or next entry, the corresponding button is hidden.

The adjacent entries are looked up in the controller using the diary entry's ID to find the nearest entry before and after in the same user's diary.

How has this been tested?

Manually verified the nav bar renders correctly above the comments section on a diary entry page.
Three test cases were added to the diary entries controller test:

• Middle entry shows both previous and next links
• First entry shows only a next link
• Last entry shows only a previous link

Screenshot

[phanq003]

Update: The implementation now includes backend logic and tests for previous/next diary entry navigation. The PR is now fully functional and fetches adjacent entries.

[pablobm]

I'll leave to maintainers to decide if this feature is desired. It makes sense to me and it's a common feature of many blogging sites, but it not strictly necessary and might be perceived as making things a bit busy.

Incidentally, for visual changes it's useful to include screenshots, so that maintainers can get a quick idea of what the change looks like before going into a proper review. Here's one:

Visuals

The first thing that caught my attention was the style of the buttons, which is a bit different to the ones normally used for pagination. Yours have a subdued grey text and relatively heavy border, compared to the existing ones with text in standard link blue and a subdued border:

Buttons in this PR	Existing pagination buttons

Looking a bit more into it, I see there's other differences, such as the use of chevrons (double angle brackets) instead of single angle brackets. I think those should be more consistent with the pagination ones.

Code organisation

In general, it's a good idea to keep controllers small. Instead of having the DB queries in the controller, I'd try to move them to DiaryEntry. These can then be easily unit-tested too.

Although that brings a little problem. Your current code has the advantage of relying of a previous filtering of invisible diary entries where appropriate. Moving the code to the model would make this a bit tricky, but I think it could be done. Instead of DiaryEntry#next, we could have DiaryEntry.first_after(entry). That should work when applied to ActiveRecord relations, such as the entries variable that you are using (entries.first_after(entry)).

[Sinty026]

Thanks for the feedback! I've updated the button styling to match the existing buttons. I'll also look into moving the logic to DiaryEntry.

I do see what you mean about it feeling a bit busy. do you have any suggestions on how to make it feel less messy?

[pablobm]

Not sure, but it's more a question for the maintainers. I'd want to hear their opinion.

Incidentally, I just had a look and saw a diary that could benefit from something like this: https://www.openstreetmap.org/user/pussreboots/diary In fact if instead of "Previous/Next entry" we had the title of the entry it would be great in this specific case. But don't go implement that yet. Let's wait for more feedback. For one, this example is not really representative of the typical diaries.