feat: image variants cache panel

internal/domain/image/variantCache.go

@@ -0,0 +1,76 @@
+package image
+
+import (
+	"errors"
+	"time"
+)
+
+var ErrCachePurgeScope = errors.New("cache purge scope is not valid")
+
+type CachePurgeScope string
+
+const (
+	CacheScopeAll     CachePurgeScope = "all"
+	CacheScopeUnused  CachePurgeScope = "unused"
+	CacheScopeVariant CachePurgeScope = "variant"
+	CacheScopeImage   CachePurgeScope = "image"
+)
+
+const (
+	UnusedVariantDays   = 30
+	RejectionWindowDays = 7
+	TopImagesLimit      = 10
+	CachePurgeBatchSize = 500
+	RejectionDayLayout  = "2006-01-02"
+)
+
+func UnusedCutoff(now time.Time) time.Time {
+	return now.UTC().AddDate(0, 0, -UnusedVariantDays)
+}
+
+func RejectionDay(at time.Time) time.Time {
+	utc := at.UTC()
+	return time.Date(utc.Year(), utc.Month(), utc.Day(), 0, 0, 0, 0, time.UTC)
+}
+
+func RejectionWindowStart(now time.Time) time.Time {
+	return RejectionDay(now).AddDate(0, 0, -(RejectionWindowDays - 1))
+}
+
+func RejectionPruneBefore(now time.Time) time.Time {
+	return RejectionDay(now).AddDate(0, 0, -RejectionWindowDays)
+}
+
+type UnusedFilter struct {
+	VariantNames []string
+	Cutoff       time.Time
+}
+
+type VariantFileFilter struct {
+	VariantName string
+	SourceName  string
+	Unused      *UnusedFilter
+}
+
+type SourceTotals struct {
+	SourceName string
+	Files      int
+	Bytes      int64
+}
+
+type VariantHit struct {
+	VariantName string
+	SourceName  string
+	At          time.Time
+}
+
+type RejectionCount struct {
+	Day   time.Time
+	Count int
+}
+
+type VariantUsageBatch struct {
+	Hits        []VariantHit
+	Rejections  []RejectionCount
+	PruneBefore time.Time
+}