Upgrade Bid Adjustments (prebid#2678)

bidadjustment/apply.go

@@ -0,0 +1,94 @@
+package bidadjustment
+
+import (
+	"math"
+
+	"github.com/prebid/prebid-server/adapters"
+	"github.com/prebid/prebid-server/openrtb_ext"
+)
+
+const (
+	AdjustmentTypeCPM        = "cpm"
+	AdjustmentTypeMultiplier = "multiplier"
+	AdjustmentTypeStatic     = "static"
+	WildCard                 = "*"
+	Delimiter                = "|"
+)
+
+const maxNumOfCombos = 8
+const pricePrecision float64 = 10000 // Rounds to 4 Decimal Places
+const minBid = 0.1
+
+// Apply gets the highest priority adjustment slice given a map of rules, and applies those adjustments to a bid's price
+func Apply(rules map[string][]openrtb_ext.Adjustment, bidInfo *adapters.TypedBid, bidderName openrtb_ext.BidderName, currency string, reqInfo *adapters.ExtraRequestInfo, bidType string) (float64, string) {
+	adjustments := []openrtb_ext.Adjustment{}
+	if len(rules) > 0 {
+		adjustments = get(rules, bidType, string(bidderName), bidInfo.Bid.DealID)
+	} else {
+		return bidInfo.Bid.Price, currency
+	}
+	adjustedPrice, adjustedCurrency := apply(adjustments, bidInfo.Bid.Price, currency, reqInfo)
+
+	if bidInfo.Bid.DealID != "" && adjustedPrice < 0 {
+		return 0, currency
+	}
+	if bidInfo.Bid.DealID == "" && adjustedPrice <= 0 {
+		return minBid, currency
+	}
+	return adjustedPrice, adjustedCurrency
+}
+
+func apply(adjustments []openrtb_ext.Adjustment, bidPrice float64, currency string, reqInfo *adapters.ExtraRequestInfo) (float64, string) {
+	if len(adjustments) == 0 {
+		return bidPrice, currency
+	}
+	originalBidPrice := bidPrice
+
+	for _, adjustment := range adjustments {
+		switch adjustment.Type {
+		case AdjustmentTypeMultiplier:
+			bidPrice = bidPrice * adjustment.Value
+		case AdjustmentTypeCPM:
+			convertedVal, err := reqInfo.ConvertCurrency(adjustment.Value, adjustment.Currency, currency)
+			if err != nil {
+				return originalBidPrice, currency
+			}
+			bidPrice = bidPrice - convertedVal
+		case AdjustmentTypeStatic:
+			bidPrice = adjustment.Value
+			currency = adjustment.Currency
+		}
+	}
+	roundedBidPrice := math.Round(bidPrice*pricePrecision) / pricePrecision
+
+	return roundedBidPrice, currency
+}
+
+// get() should return the highest priority slice of adjustments from the map that we can match with the given bid info
+// given the bid info, we create the same format of combinations that's present in the key of the ruleToAdjustments map
+// the slice is ordered by priority from highest to lowest, as soon as we find a match, we return that slice
+func get(rules map[string][]openrtb_ext.Adjustment, bidType, bidderName, dealID string) []openrtb_ext.Adjustment {
+	priorityRules := [maxNumOfCombos]string{}
+	if dealID != "" {
+		priorityRules[0] = bidType + Delimiter + bidderName + Delimiter + dealID
+		priorityRules[1] = bidType + Delimiter + bidderName + Delimiter + WildCard
+		priorityRules[2] = bidType + Delimiter + WildCard + Delimiter + dealID
+		priorityRules[3] = WildCard + Delimiter + bidderName + Delimiter + dealID
+		priorityRules[4] = bidType + Delimiter + WildCard + Delimiter + WildCard
+		priorityRules[5] = WildCard + Delimiter + bidderName + Delimiter + WildCard
+		priorityRules[6] = WildCard + Delimiter + WildCard + Delimiter + dealID
+		priorityRules[7] = WildCard + Delimiter + WildCard + Delimiter + WildCard
+	} else {
+		priorityRules[0] = bidType + Delimiter + bidderName + Delimiter + WildCard
+		priorityRules[1] = bidType + Delimiter + WildCard + Delimiter + WildCard
+		priorityRules[2] = WildCard + Delimiter + bidderName + Delimiter + WildCard
+		priorityRules[3] = WildCard + Delimiter + WildCard + Delimiter + WildCard
+	}
+
+	for _, rule := range priorityRules {
+		if _, ok := rules[rule]; ok {
+			return rules[rule]
+		}
+	}
+	return nil
+}