feat: #796 - added a "refresh products" button to history page

[monsieurtanuki]

Impacted file:

• product_list_page.dart: added a "refresh products" button; refactored

Screenshot

@teolemon I 'm sure you won't like the UI, but at least the feature is there. Note the additional refresh icon on the app bar:

Part of

• Fix refresh strategy for the history #796

Additional thoughts

It's not that easy to test that feature, as there's no real product timestamp.

[M123-dev]

Code looks good, but we have to keep one thing in mind, what happens when refreshing the history list when you are a long time User with possibly thousands of products.

We should handle them one by one. So update the first, put the first into storage, update a progress indicator and then go to the next one

[monsieurtanuki]

Code looks good, but we have to keep one thing in mind, what happens when refreshing the history list when you are a long time User with possibly thousands of products.

You're right, but we will have the same problem displaying the list, which means loading 1000s of products in memory.
Then other performance issues like "is it better to fetch 1000 products in one query" / "100 products each in 10 queries" / "10 products each in 100 queries"? Let alone the fact that for that query we use a URL that concatenates the barcodes: we may reach the limits very soon (is that 1024 characters?).
All those questions could be dealt with in a specific "performance vs. number of products" issue.

[monsieurtanuki]

@M123-dev Besides, I don't think it makes sense to keep 1000s of products in the history.
Thank you for the review btw ;)