Implement guided packaging input (wizard-like)

[teolemon]

Who for

• As a user who cares about the Eco-Score, I would like to be able to input packaging easily, possibly with help from Open Food Facts

What

Packaging input wizard (important and urgent)

Dart side

• Add openfoodfacts-dart support for reading and writing the new packaging structure
  • curl -X POST https://off:[email protected]/api/v3/product/12345678 -H "Content-Type: application/json" -d '{"product": { "packagings_add": [{"shape": "bottle"}]}, "fields": "updated"}'
    {"errors":[],"product":{"packagings":[{"shape":"en:bottle"}]},"warnings":[{"field":{"default_value":"en","id":"tags_lc"},"impact":{"id":"warning"},"message":{"id":"missing_tags_lc"}},{"field":{"id":"number_of_units"},"impact":{"id":"field_ignored"},"message":{"id":"packaging_component_missing_number_of_units"}},{"field":{"id":"recycling","value":null},"impact":{"id":"field_ignored"},"message":{"id":"packaging_component_missing_recycling"}},{"field":{"id":"material","value":null},"impact":{"id":"field_ignored"},"message":{"id":"packaging_component_missing_material"}}]}
• feat: Start of implementation of API v3 product read and write + integration tests openfoodfacts-server#7614
• Add support for API v3 Product WRITE requests to add / edit packaging components openfoodfacts-dart#617

Overall structure / Entry point

• Add screen listing all of the existing packaging pieces, with an option to add more pieces manually #3431

Shapes

• Allow to add/edit packaging shapes #3309

Materials

• Allow to add/edit packaging materials #3310

Weight

• Allow to add/edit packaging weight #3312

Scale precision - Dropped for initial implementation

• Support for scale precision - dropped for initial implementation #3311

Old Design doc

For later

• Add server support for all the various shapes icons
• Create a list of the material icons we currently have deployed (in packaging + labels)
• Create a system to extract the recycling instructions from the packaging image (France-only ?)
  • Reuse the mechanism for ingredients extraction for packagings #1070

Why

Part of

• Implement improved contribution flow in app #505
• Product addition (tracker) #1379

[monsieurtanuki]

@teolemon We cannot do that for the moment for several reasons:

1. the packaging data does not look like that in Product - basically it's just a List of tags or labels, without structure
   => we would need a new corresponding issue to be created on off-dart, or perhaps even on the server side
2. again, I'm not a big fan of those trees - if you get (just) the root packagings like in https://world.openfoodfacts.org/api/v2/taxonomy?tagtype=packaging&include_root_entries=1&include_children=0&lc=fr&cc=fr you get 122 items, with no relevant order, and I don't think end-users would enjoy scrolling 122 items to find "cardboard", let alone a child of "cardboard"
   => we would need either a relevancy ordering, but I would rather be in favor of autocompleted text input, possibly with a "favorite/previous" packagings suggestion
3. there's no way to distinguish material from shape; the only fields we have for packaging are "name" and "synonyms" (and "parents" / "children")

[teolemon]

We might have to reopen that one, and add weight input as well

[monsieurtanuki]

@teolemon Why not, if we know which parameters we need to provide to the server.

[teolemon]

@monsieurtanuki we're videomeeting at 2PM on the topic of packaging