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
}