Initial commit

internal/scheduler/badge.go

@@ -0,0 +1,76 @@
+package scheduler
+
+import (
+	"fmt"
+	"time"
+
+	"veola/internal/models"
+	"veola/templates"
+)
+
+// PickBadge returns the highest-priority deal-quality badge that applies to
+// an item, or an empty BadgeData if none match. Order:
+//  1. All-time low
+//  2. X% below 30-day avg (only when at least 10% below)
+//  3. X% below target
+func PickBadge(it models.Item, history []models.PricePoint, now time.Time) templates.BadgeData {
+	if it.BestPrice == nil {
+		return templates.BadgeData{}
+	}
+	best := *it.BestPrice
+
+	// 1. All-time low
+	if isAllTimeLow(best, history) {
+		return templates.BadgeData{Label: "All-time low", Class: "v-badge-low"}
+	}
+
+	// 2. X% below 30-day average
+	if avg, ok := windowedMean(history, now, 30*24*time.Hour); ok && best > 0 && avg > 0 {
+		pct := (avg - best) / avg * 100
+		if pct >= 10 {
+			return templates.BadgeData{
+				Label: fmt.Sprintf("%d%% below 30-day avg", int(pct+0.5)),
+				Class: "v-badge-avg",
+			}
+		}
+	}
+
+	// 3. X% below target
+	if it.TargetPrice != nil && *it.TargetPrice > 0 && best < *it.TargetPrice {
+		pct := (*it.TargetPrice - best) / *it.TargetPrice * 100
+		return templates.BadgeData{
+			Label: fmt.Sprintf("%d%% below target", int(pct+0.5)),
+			Class: "v-badge-target",
+		}
+	}
+
+	return templates.BadgeData{}
+}
+
+func isAllTimeLow(best float64, history []models.PricePoint) bool {
+	if len(history) == 0 {
+		return false
+	}
+	for _, p := range history {
+		if p.Price > 0 && p.Price < best {
+			return false
+		}
+	}
+	return true
+}
+
+func windowedMean(history []models.PricePoint, now time.Time, window time.Duration) (float64, bool) {
+	cutoff := now.Add(-window)
+	sum, n := 0.0, 0
+	for _, p := range history {
+		if p.PolledAt.Before(cutoff) {
+			continue
+		}
+		sum += p.Price
+		n++
+	}
+	if n == 0 {
+		return 0, false
+	}
+	return sum / float64(n), true
+}