package runners

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

	"github.com/google/uuid"
)

// AttachmentRow projects the chat.AttachmentRef fields the cleanup needs. The
// production adapter (T16) maps chat.AttachmentRef → AttachmentRow 1:1.
type AttachmentRow struct {
	ID          uuid.UUID
	StoragePath string
}

// AttachmentCleanupRepo is the minimal repo surface needed. olderThan matches
// chat.Repository's existing signature (time.Duration, not absolute cutoff).
type AttachmentCleanupRepo interface {
	ListAttachmentsForSoftDeletedConversations(ctx context.Context, olderThan time.Duration) ([]AttachmentRow, error)
	ListExpiredOrphans(ctx context.Context, olderThan time.Duration) ([]AttachmentRow, error)
	DeleteAttachments(ctx context.Context, ids []uuid.UUID) error
}

// AttachmentStorage is the storage.Storage surface for delete.
type AttachmentStorage interface {
	Delete(ctx context.Context, storagePath string) error
}

// AttachmentCleanupConfig matches jobs.AttachmentCleanupConfig minus enabled/interval.
type AttachmentCleanupConfig struct {
	Retention time.Duration
}

// AttachmentCleanup is the C runner: clears both soft-deleted-conversation
// attachments and orphan attachments older than Retention.
type AttachmentCleanup struct {
	repo AttachmentCleanupRepo
	st   AttachmentStorage
	cfg  AttachmentCleanupConfig
	log  *slog.Logger
}

// NewAttachmentCleanup constructs the runner.
func NewAttachmentCleanup(repo AttachmentCleanupRepo, st AttachmentStorage, cfg AttachmentCleanupConfig, log *slog.Logger) *AttachmentCleanup {
	if log == nil {
		log = slog.Default()
	}
	return &AttachmentCleanup{repo: repo, st: st, cfg: cfg, log: log}
}

// Run runs both subphases.
func (r *AttachmentCleanup) Run(ctx context.Context) {
	r.cleanup(ctx, "soft_deleted", func(ctx context.Context) ([]AttachmentRow, error) {
		return r.repo.ListAttachmentsForSoftDeletedConversations(ctx, r.cfg.Retention)
	})
	r.cleanup(ctx, "orphan", func(ctx context.Context) ([]AttachmentRow, error) {
		return r.repo.ListExpiredOrphans(ctx, r.cfg.Retention)
	})
}

func (r *AttachmentCleanup) cleanup(ctx context.Context, label string, list func(ctx context.Context) ([]AttachmentRow, error)) {
	rows, err := list(ctx)
	if err != nil {
		r.log.Error("attachment_cleanup.list", "label", label, "err", err.Error())
		return
	}
	if len(rows) == 0 {
		return
	}
	deletedIDs := make([]uuid.UUID, 0, len(rows))
	for _, row := range rows {
		if err := r.st.Delete(ctx, row.StoragePath); err != nil {
			r.log.Warn("attachment_cleanup.storage_delete_failed",
				"label", label, "id", row.ID, "path", row.StoragePath, "err", err.Error())
			continue
		}
		deletedIDs = append(deletedIDs, row.ID)
	}
	if len(deletedIDs) == 0 {
		return
	}
	if err := r.repo.DeleteAttachments(ctx, deletedIDs); err != nil {
		r.log.Error("attachment_cleanup.db_delete", "label", label, "err", err.Error())
	}
}