package models

/*
The nutrition panel, as the customer app renders it.

The figures come from the catalogue-intelligence service — the same one behind
the health score card in the console — and this is the shape they reach the app
in. See services/nutritionService.go for the fetch and the mapping.

── Why the field names are ugly ────────────────────────────────────────────

`servingsize`, not `serving_size` or `servingSize`. This is the shape the app
developer asked for, and an API is a promise to a client already written against
it. Consistency with the rest of Fiesta — itself inconsistent, `productid`
beside `image_id` beside `sku_source` — is worth less than not breaking the
caller.
*/
type NutritionPanel struct {
	// What the figures are measured against. "100g" for everything the service
	// returns today: its top-level values are per 100g, which is what the
	// console's own panel prints beneath them.
	Per string `json:"per,omitempty"`
	// What the pack calls one serving — "1 mini (11 g)". Absent when the
	// service did not state one, rather than defaulted: a serving size is a
	// claim about the food, and a guessed one is a false claim.
	Servingsize string `json:"servingsize,omitempty"`
	// Never nil when this panel exists — see HasValues. An app receiving
	// `items: null` has to branch; one receiving `[]` does not, and a panel with
	// no rows should not have been sent at all.
	Items []NutritionItem `json:"items"`
}

// NutritionItem is one line of the panel.
type NutritionItem struct {
	Name string `json:"name"`
	// The figure. A float because saturated fat is 18.7g as often as it is 19g,
	// and rounding it to please a type would be editing a label.
	Value float64 `json:"value"`
	// "kcal", "g", "mg". Free text on purpose: `extended_nutrients` carries its
	// own units from the source, and a closed list here would mean refusing to
	// carry whatever the label actually says.
	Unit string `json:"unit,omitempty"`
}

// HasValues reports whether this panel is worth sending.
//
// A panel with no rows is not a panel — it is an empty box on a product page,
// which a shopper reads as "this food has no nutrition" rather than "we do not
// know yet". The endpoint omits it instead.
func (p *NutritionPanel) HasValues() bool {
	return p != nil && len(p.Items) > 0
}