Implement the API to change the default language of a product

[g123k]

TODO find this API ;)

[monsieurtanuki]

cf #812

Not sure that field exists, or even the concept.
I cannot see that on the website.

[g123k]

That's this field on the website

[monsieurtanuki]

@g123k We already support that field, it's ProductField.LANGUAGE.

For the record:

• it doesn't look that important as it's not displayed in the website, except when you edit a product (and it's not that obvious either)
• we kind of already set that value in Smoothie each time we change product details (cf. BackgroundTaskDetails), as it looked like it provided better results for multilingual texts (or rare cases of products with only monolingual settings, can't remember). We set it to the current app language.

[g123k]

@g123k We already support that field, it's ProductField.LANGUAGE.

For the record:

• it doesn't look that important as it's not displayed in the website, except when you edit a product (and it's not that obvious either)
• we kind of already set that value in Smoothie each time we change product details (cf. BackgroundTaskDetails), as it looked like it provided better results for multilingual texts (or rare cases of products with only monolingual settings, can't remember). We set it to the current app language.

Mmmm, in that case, the implementation may be incorrect.
When we add a new product, it probably needs to be the same as the front picture (or one of the pictures).
But after the product creation, we shouldn't change it (unless we implement the feature to change it).

[teolemon]

It's basically lang

<select name="lang" id="lang">
                    
                        <option value="ab">Abkhaz</option>
                    

Also, if you select a new lang, we have a toggle to move images and data to main language that appears

<input class="move_data_and_images_to_main_language_checkbox" type="checkbox" id="move_en_data_and_images_to_main_language" name="move_en_data_and_images_to_main_language">

 
<div class="move_data_and_images_to_main_language" id="move_en_data_and_images_to_main_language_div" style="">
   <input class="move_data_and_images_to_main_language_checkbox" type="checkbox" id="move_en_data_and_images_to_main_language" name="move_en_data_and_images_to_main_language">
   <label for="move_en_data_and_images_to_main_language" class="checkbox_label">Move all data and selected photos in <span class="tab_language">English</span> to the main language of the product: <span class="main_language">Finnish</span></label><br>
   <div id="move_en_data_and_images_to_main_language_radio" style="display: block;">
      <input type="radio" id="move_en_data_and_images_to_main_language_replace" value="replace" name="move_en_data_and_images_to_main_language_mode" checked="" class="move_and_replace" style="margin-left:1rem;">
      <label for="move_en_data_and_images_to_main_language_replace" style="margin-top:0">Replace existing values and selected photos</label>
      <input type="radio" id="move_en_data_and_images_to_main_language_ignore" value="ignore" name="move_en_data_and_images_to_main_language_mode">
      <label for="move_en_data_and_images_to_main_language_ignore" style="margin-top:0">Keep existing values and selected photos</label><br>
   </div>
</div>

This is all processed when you hit save. I don't believe it's some JS magic, but given that, I might be wrong: https://github.com/openfoodfacts/openfoodfacts-server/blob/main/html/js/product-multilingual.js#L1008