//go:build scrub
// +build scrub

package extensions

import (
	"errors"
	"io"
	"time"

	"zotregistry.io/zot/pkg/api/config"
	"zotregistry.io/zot/pkg/extensions/scrub"
	"zotregistry.io/zot/pkg/log"
	"zotregistry.io/zot/pkg/scheduler"
	"zotregistry.io/zot/pkg/storage"
)

// EnableScrubExtension enables scrub extension.
func EnableScrubExtension(config *config.Config, log log.Logger, storeController storage.StoreController,
	sch *scheduler.Scheduler,
) {
	if config.Extensions.Scrub != nil &&
		*config.Extensions.Scrub.Enable {
		minScrubInterval, _ := time.ParseDuration("2h")

		if config.Extensions.Scrub.Interval < minScrubInterval {
			config.Extensions.Scrub.Interval = minScrubInterval

			log.Warn().Msg("Scrub interval set to too-short interval < 2h, changing scrub duration to 2 hours and continuing.") //nolint:lll // gofumpt conflicts with lll
		}

		generator := &taskGenerator{
			imgStore: storeController.DefaultStore,
			log:      log,
		}
		sch.SubmitGenerator(generator, config.Extensions.Scrub.Interval, scheduler.LowPriority)

		if config.Storage.SubPaths != nil {
			for route := range config.Storage.SubPaths {
				generator := &taskGenerator{
					imgStore: storeController.SubStore[route],
					log:      log,
				}
				sch.SubmitGenerator(generator, config.Extensions.Scrub.Interval, scheduler.LowPriority)
			}
		}
	} else {
		log.Info().Msg("Scrub config not provided, skipping scrub")
	}
}

type taskGenerator struct {
	imgStore storage.ImageStore
	log      log.Logger
	lastRepo string
	done     bool
}

func (gen *taskGenerator) GenerateTask() (scheduler.Task, error) {
	repo, err := gen.imgStore.GetNextRepository(gen.lastRepo)

	if err != nil && !errors.Is(err, io.EOF) {
		return nil, err
	}

	if repo == "" {
		gen.done = true

		return nil, nil
	}

	gen.lastRepo = repo

	return scrub.NewTask(gen.imgStore, repo, gen.log), nil
}

func (gen *taskGenerator) IsDone() bool {
	return gen.done
}

func (gen *taskGenerator) Reset() {
	gen.lastRepo = ""
	gen.done = false
}