feat(insurance): preserve selected comparison amounts

pkg/insurance/amounts.go

@@ -0,0 +1,17 @@
+package insurance
+
+import (
+	"errors"
+	"math/big"
+)
+
+func nonnegativeRat(n wireNum) (*big.Rat, error) {
+	r, err := requiredRat(n)
+	if err != nil {
+		return nil, err
+	}
+	if r.Sign() < 0 {
+		return nil, errors.New("must be nonnegative")
+	}
+	return r, nil
+}

pkg/insurance/quote.go

@@ -217,12 +217,11 @@ func (w wireHypothetical) toHypothetical() (Hypothetical, error) {
 }
 
 // wireOfferEntry mirrors the consumed subset of OfferComparisonEntry.
-// selected_amount and offer_org_id feed the vendor's update operation and are
-// deliberately not decoded.
 type wireOfferEntry struct {
-	IsCurrent *bool  `json:"is_current"`
-	OfferID   string `json:"offer_id"`
-	Offer     *struct {
+	IsCurrent      *bool   `json:"is_current"`
+	OfferID        string  `json:"offer_id"`
+	SelectedAmount wireNum `json:"selected_amount"`
+	Offer          *struct {
 		Provider              *string `json:"provider"`
 		Region                *string `json:"region"`
 		GuaranteedDisplayName *string `json:"guaranteed_display_name"`
@@ -273,11 +272,15 @@ func (w *wireOfferEntry) toOfferEntry() (OfferEntry, error) {
 	}
 	e.IsCurrent = *w.IsCurrent
 	e.OfferID = w.OfferID
+	amount, err := nonnegativeRat(w.SelectedAmount)
+	if err != nil {
+		return e, fmt.Errorf("selected_amount: %w", err)
+	}
+	e.SelectedAmount = amount
 	e.CommitmentType = w.CommitmentType
 	e.LeaseMenuItemID = w.LeaseMenuItemID
 	e.GuaranteedDisplayName = w.Offer.GuaranteedDisplayName
 	e.Region = w.Offer.Region
-	var err error
 	if e.Provider, err = parseProvider(w.Offer.Provider); err != nil {
 		return e, fmt.Errorf("offer.provider: %w", err)
 	}

pkg/insurance/quote_test.go

@@ -122,6 +122,7 @@ func TestDecodeComparison_Golden(t *testing.T) {
 	row := c.Rows[0]
 	assert.Equal(t, "22222222-2222-4222-8222-222222222222", row.LineItemID)
 	assert.True(t, row.Current.IsCurrent)
+	assert.Equal(t, rat(t, "3"), row.Current.SelectedAmount)
 	assert.False(t, row.Current.LeaseBacked())
 	assert.Nil(t, row.Current.ContractTerm)
 	assert.Nil(t, row.Current.PaymentOption)
@@ -141,6 +142,19 @@ func TestDecodeComparison_Golden(t *testing.T) {
 	assert.Nil(t, cand.Delta.BreakevenDays)
 }
 
+func TestDecodeComparisonSelectedAmount(t *testing.T) {
+	t.Parallel()
+	for _, value := range []string{"null", "-1", `"3"`} {
+		_, err := decodeComparison(t, strings.ReplaceAll(validComparisonJSON(), `"selected_amount": 3`, `"selected_amount": `+value))
+		require.ErrorContains(t, err, "selected_amount")
+	}
+	_, err := decodeComparison(t, strings.ReplaceAll(validComparisonJSON(), `"selected_amount": 3,`, ``))
+	require.ErrorContains(t, err, "selected_amount")
+	c, err := decodeComparison(t, strings.ReplaceAll(validComparisonJSON(), `"selected_amount": 3`, `"selected_amount": 0.1234567890123456789`))
+	require.NoError(t, err)
+	assert.Equal(t, rat(t, "0.1234567890123456789"), c.Rows[0].Current.SelectedAmount)
+}
+
 func TestDecodeComparison_EmptyArraysAreValid(t *testing.T) {
 	c, err := decodeComparison(t, `{
 		"current_totals": {"commitment_financials_monthly_rate": {}, "commitment_upfront_cost": 0},
@@ -428,6 +442,7 @@ func TestDecodeComparison_DistinctValuesForEveryMappedField(t *testing.T) {
 			"line_item_id": "bbbbbbbb-bbbb-4bbb-8bbb-bbbbbbbbbbbb",
 			"current": {
 				"is_current": true, "offer_id": "cccccccc-cccc-4ccc-8ccc-cccccccccccc",
+				"selected_amount": 3.25,
 				"offer": {"provider": "gcp", "region": "europe-west4", "guaranteed_display_name": "Current G"},
 				"lease_menu_item_id": null, "commitment_type": "gcp/cud",
 				"contract_term": "three_year", "payment_option": "all_upfront",
@@ -437,6 +452,7 @@ func TestDecodeComparison_DistinctValuesForEveryMappedField(t *testing.T) {
 			},
 			"candidates": [{
 				"is_current": false, "offer_id": "dddddddd-dddd-4ddd-8ddd-dddddddddddd",
+				"selected_amount": 4.125,
 				"offer": {"provider": "azure", "region": "eu-west-1", "guaranteed_display_name": "Cand G"},
 				"lease_menu_item_id": "eeeeeeee-eeee-4eee-8eee-eeeeeeeeeeee", "commitment_type": "azure/Virtual Machines",
 				"contract_term": "one_year_gris", "payment_option": "partial_upfront",
@@ -480,6 +496,7 @@ func TestDecodeComparison_DistinctValuesForEveryMappedField(t *testing.T) {
 	cur := row.Current
 	assert.True(t, cur.IsCurrent)
 	assert.Equal(t, "cccccccc-cccc-4ccc-8ccc-cccccccccccc", cur.OfferID)
+	assert.Equal(t, rat(t, "3.25"), cur.SelectedAmount)
 	assert.Equal(t, "gcp/cud", cur.CommitmentType)
 	assert.Equal(t, common.ProviderGCP, cur.Provider)
 	require.NotNil(t, cur.Region)
@@ -497,6 +514,7 @@ func TestDecodeComparison_DistinctValuesForEveryMappedField(t *testing.T) {
 	cand := row.Candidates[0]
 	assert.False(t, cand.IsCurrent)
 	assert.Equal(t, "dddddddd-dddd-4ddd-8ddd-dddddddddddd", cand.OfferID)
+	assert.Equal(t, rat(t, "4.125"), cand.SelectedAmount)
 	assert.Equal(t, "azure/Virtual Machines", cand.CommitmentType)
 	assert.Equal(t, common.ProviderAzure, cand.Provider)
 	require.NotNil(t, cand.Region)

pkg/insurance/types.go

@@ -135,14 +135,14 @@ type OfferDelta struct {
 }
 
 // OfferEntry mirrors the consumed subset of OfferComparisonEntry: one offer
-// (current or candidate) for a line item. Fields that feed the vendor's
-// line-item update operation (selected_amount, offer_org_id) are deliberately
-// not mapped.
+// (current or candidate) for a line item.
 type OfferEntry struct {
 	// IsCurrent is true when this entry matches the line item's current
 	// offer and lease.
 	IsCurrent bool
 	OfferID   string
+	// SelectedAmount is a count for RI/unit CUD, or $/hour for spend commitments.
+	SelectedAmount *big.Rat
 	// CommitmentType is the vendor's offer type string. The docs give both
 	// "aws/AmazonEC2"-style and "ri"/"savings_plan"/"cud"-style examples;
 	// treat it as opaque display text.