In Drupal Commerce, which hook do I use to alter product entity data in a product display?** And it needs to be a hook that fires each time I change an attribute that causes a different product entity to be loaded in the display.
I added a line item to my product type called "Comments". It is a textarea, and it has a field description too. Then, on my product type, I added the following fields:
Customizable? (On/Off checkbox)
Custom Field Label
Custom Field Description
As each product entity is about to be displayed (whether it's the first one shown when the page loads, or I make a drop down selection to change which one shows), I want to check if that product entity is "Customizable". If it is, I want to rename the title of the "Comments" line item with the value stored in "Custom Field Label". And I want to change the Comments field description with the value stored in "Custom Field Description". If the product entity is NOT "Customizable", then I want to hide the field completely (such as by converting the field type from a textarea to a hidden field). This way, the "Comments" line item really only shows for the product entities we want it to, and it can have a custom label and instruction when it does show.
Any help someone can give is greatly appreciated. I am having a lot of trouble even figuring out which hook fires each time a product entity is loaded, either the first time, or when switched via ajax.