[6.x] Add hooks for localization switching

[tao]

As discussed in #12328, and potentially related to the collaboration plugin issue #90 it would be helpful to have hooks available when the sites are selected or created in the multisite selector.

This pull requests adds 4 new hooks:

• localization.selecting
• localization.selected
• localization.creating
• localization.created

The createLocalization and editLocalization functions both use the same editLocalizationRequest axios request, but I have ensured that only the correct events are fired in either scenario.

The localization.selecting and localization.creating hooks provides the newly selected locale in the payload:

 Statamic.$hooks.on('localization.selecting', (resolve, reject, payload) => {
        let localization = payload.localization
        //
        resolve()
    })

// payload.localization
{
    active: false
    ​​​exists: true
    ​​​handle: "it"
    ​​​livePreviewUrl: "http://localhost:8000/cp/collections/speeches/entries/9f154338-8ff7-4021-a88a-5cc901cbe024/preview"
    name: "Italian"
    origin: false
    published: false​
    root: false
    ​​​status: "draft"​​
    url: "http://localhost:8000/cp/collections/speeches/entries/9f154338-8ff7-4021-a88a-5cc901cbe024"
}

While the localization.selected and localization.created hooks provide the localization and the response from the editLocalization request, which includes data about the current entry:

    Statamic.$hooks.on('localization.selected', (resolve, reject, payload) => {
        let localization = payload.localization
        let entry = payload.entry
        //
        resolve()
    })

// payload.entry
{
    "title": "1994 International UFO Congress",
    "description": "..."
    "content": "",
    "location": "Laughlin, NV",
    "slug": "international-ufo-congress",
    "date": "1994-03-08T00:00:00.000Z",
    "updated_at": 1757157846,
    "published_at": "2008-06-17",
    "published": false,
    "id": "cf03f1eb-c4ef-42bb-80d4-b0a811c8ee62"
}

At the moment, only the entry values are returned in the payload, but if some other values are necessary then they can be included from the response object... I don't specifically need the values for my use-case by perhaps in the future (or for the collab plugin bug) it would be useful to have the entry ID available when creating a new broadcast channel.

These events allow me to detect when a language changes and update the text direction of the Control Panel

    Statamic.$hooks.on('localization.selected', (resolve, reject, payload) => {
        let locale = payload.localization.handle;
        let direction = ['fa', 'he'].includes(locale) ? 'rtl' : 'ltr';
        
        // update the publish fields
        document.querySelector('.publish-fields').setAttribute('dir', direction);
        
        // update the full screen markdown editor
        document.querySelector('.portal-targets')?.setAttribute('dir', direction)

        resolve()
    })

It would be nice if we could use the localization.created or localization.creating hooks to update values automatically, like allowing for the automatic translation of some fields with an API and resolve() back the new entry data, but I think that might be better to handle on the Laravel side instead of the frontend?

I did examine the frontend tests folder and I couldn't see any tests for specific hooks, so I wasn't sure how to go about including those.

[jasonvarga]

Hey @tao can you check out #13024

Would that PR make this one unnecessary?

[jasonvarga]

Closing this under the assumption that #13024 is enough to solve your issue. We can reopen if need be though.

[tao]

It's amazing! I'm so happy that this has been implemented finally. #13024 works great except for the text direction of the full-screen markdown window... but I'll see if I can make a pull-request for that using the same solution.