package useCases

import (
	"RenewCMS/internal/domain/article"
	"RenewCMS/internal/domain/author"
	"RenewCMS/internal/domain/image"
	"RenewCMS/internal/domain/site"
)

const purgePreviewListLimit = 5

type PurgePreviewGroup struct {
	KeepID   uint32
	Filename string
	URL      string
	UsedIn   int
	Merged   int
}

type PurgePreview struct {
	Groups      int
	Copies      int
	Articles    int
	List        []PurgePreviewGroup
	More        int
	Fingerprint string
}

type PreviewPurgeUseCase struct {
	planner *purgePlanner
}

func NewPreviewPurgeUseCase(imageRepository image.Repository, articleRepository article.Repository, sites site.Repository, authors author.Repository) *PreviewPurgeUseCase {
	return &PreviewPurgeUseCase{&purgePlanner{imageRepository: imageRepository, articleRepository: articleRepository, sites: sites, authors: authors}}
}

func (u *PreviewPurgeUseCase) Preview() (PurgePreview, error) {
	plan, err := u.planner.plan()
	if err != nil {
		return PurgePreview{}, err
	}

	shown := min(len(plan.groups), purgePreviewListLimit)
	list := make([]PurgePreviewGroup, 0, shown)
	for _, group := range plan.groups[:shown] {
		list = append(list, PurgePreviewGroup{
			KeepID:   group.kept.ID,
			Filename: group.kept.Filename,
			URL:      group.kept.Path,
			UsedIn:   group.keptUsage,
			Merged:   len(group.mergedIds),
		})
	}

	return PurgePreview{
		Groups:      len(plan.groups),
		Copies:      plan.copies,
		Articles:    plan.articles,
		List:        list,
		More:        len(plan.groups) - shown,
		Fingerprint: plan.fingerprint,
	}, nil
}