Deduplicate configuration revisions and update revisions UI

internal/localdb/snapshots.go

@@ -3,6 +3,7 @@ package localdb
 import (
 	"encoding/json"
 	"fmt"
+	"sort"
 	"time"
 )
 
@@ -94,3 +95,51 @@ func DecodeConfigurationSnapshot(data string) (*LocalConfiguration, error) {
 		OriginalUsername: snapshot.OriginalUsername,
 	}, nil
 }
+
+type configurationSpecPriceFingerprint struct {
+	Items       []configurationSpecPriceFingerprintItem `json:"items"`
+	ServerCount int                                     `json:"server_count"`
+	TotalPrice  *float64                                `json:"total_price,omitempty"`
+	CustomPrice *float64                                `json:"custom_price,omitempty"`
+}
+
+type configurationSpecPriceFingerprintItem struct {
+	LotName   string  `json:"lot_name"`
+	Quantity  int     `json:"quantity"`
+	UnitPrice float64 `json:"unit_price"`
+}
+
+// BuildConfigurationSpecPriceFingerprint returns a stable JSON key based on
+// spec + price fields only, used for revision deduplication.
+func BuildConfigurationSpecPriceFingerprint(localCfg *LocalConfiguration) (string, error) {
+	items := make([]configurationSpecPriceFingerprintItem, 0, len(localCfg.Items))
+	for _, item := range localCfg.Items {
+		items = append(items, configurationSpecPriceFingerprintItem{
+			LotName:   item.LotName,
+			Quantity:  item.Quantity,
+			UnitPrice: item.UnitPrice,
+		})
+	}
+	sort.Slice(items, func(i, j int) bool {
+		if items[i].LotName != items[j].LotName {
+			return items[i].LotName < items[j].LotName
+		}
+		if items[i].Quantity != items[j].Quantity {
+			return items[i].Quantity < items[j].Quantity
+		}
+		return items[i].UnitPrice < items[j].UnitPrice
+	})
+
+	payload := configurationSpecPriceFingerprint{
+		Items:       items,
+		ServerCount: localCfg.ServerCount,
+		TotalPrice:  localCfg.TotalPrice,
+		CustomPrice: localCfg.CustomPrice,
+	}
+
+	raw, err := json.Marshal(payload)
+	if err != nil {
+		return "", fmt.Errorf("marshal spec+price fingerprint: %w", err)
+	}
+	return string(raw), nil
+}