feat: image variants cache panel

internal/domain/image/imageRepositoryInterface.go

@@ -15,6 +15,7 @@ type Repository interface {
 	ListDuplicates() ([]Image, error)
 	Counts() (Counts, error)
 	ExistsByStoredName(storedName string) (bool, error)
+	ListByStoredNames(storedNames []string) ([]Image, error)
 	ListMissingMetadata() ([]Image, error)
 	UpdateMetadata(id uint32, metadata Metadata) error
 }

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
+}

internal/domain/image/variantRepositoryInterface.go

@@ -1,6 +1,9 @@
 package image
 
-import "io"
+import (
+	"io"
+	"time"
+)
 
 type VariantRepository interface {
 	List() ([]Variant, error)
@@ -20,6 +23,23 @@ type VariantFileRepository interface {
 	TotalsBySource() (map[string]VariantFileTotals, error)
 }
 
+type VariantCacheRepository interface {
+	UnusedTotals(filter UnusedFilter) (VariantFileTotals, error)
+	TopSources(limit int) ([]SourceTotals, error)
+	ListPage(filter VariantFileFilter, afterID uint32, limit int) ([]VariantFile, error)
+}
+
+type VariantUsageRepository interface {
+	Record(batch VariantUsageBatch) error
+	RejectedSince(day time.Time) (int, error)
+}
+
+type VariantUsageTracker interface {
+	RecordHit(variantName string, sourceName string)
+	RecordRejection()
+	Flush() error
+}
+
 type RenderedVariant struct {
 	Content     []byte
 	ContentType string