package scheduler

import (
	"context"
	"log/slog"
	"time"

	"filefast/backend/internal/storage"
	"filefast/backend/internal/store"

	"github.com/robfig/cron/v3"
)

type CleanupScheduler struct {
	logger      *slog.Logger
	store       *store.MemoryStore
	minioClient *storage.MinIOClient
	cron        *cron.Cron
}

func NewCleanupScheduler(logger *slog.Logger, store *store.MemoryStore, minioClient *storage.MinIOClient) *CleanupScheduler {
	return &CleanupScheduler{
		logger:      logger,
		store:       store,
		minioClient: minioClient,
		cron:        cron.New(),
	}
}

func (s *CleanupScheduler) Start() {
	_, err := s.cron.AddFunc("@daily", s.cleanupExpiredFallbacks)
	if err != nil {
		s.logger.Error("failed to register cleanup cron", "error", err)
		return
	}
	s.cron.Start()
}

func (s *CleanupScheduler) Stop() {
	ctx := s.cron.Stop()
	<-ctx.Done()
}

func (s *CleanupScheduler) cleanupExpiredFallbacks() {
	now := time.Now()
	for _, object := range s.store.ListExpiredFallbackObjects(now) {
		if s.minioClient != nil {
			if err := s.minioClient.RemoveObject(context.Background(), object.ObjectKey); err != nil {
				s.logger.Warn("failed to remove expired fallback object", "transfer_id", object.TransferID, "error", err)
				continue
			}
		}

		object.CleanupState = "cleaned"
		object.CleanedAt = &now
		s.store.SaveFallbackObject(object)
		s.logger.Info("cleaned expired fallback object", "transfer_id", object.TransferID, "object_key", object.ObjectKey)
	}
}