package logic

import (
	"context"

	"spark-server/internal/module/upload/entity"
	"spark-server/internal/pkg/errs"
	"spark-server/internal/pkg/i18n"
	"spark-server/internal/pkg/reqctx"
	"spark-server/internal/pkg/validate"
)

// DownloadInput requests a short-lived GET URL for an already-uploaded object key.
type DownloadInput struct {
	ObjectKey string `json:"object_key" validate:"required,max=512" label:"field.object_key" errmsg:"required:validate.upload.key_required;max:validate.upload.key_invalid"`
}

func (s *Service) CreateDownload(ctx context.Context, userID int64, in *DownloadInput) (*entity.Download, error) {
	if !s.ready() {
		return nil, errs.ErrAvailable
	}
	if userID <= 0 {
		return nil, errs.ErrUnauthorized
	}
	if in == nil {
		return nil, errs.ErrInvalidArgument
	}
	if err := validate.StructLang(reqctx.Lang(ctx), in); err != nil {
		return nil, err
	}
	if !s.allow(userID) {
		return nil, errs.ErrRateLimited
	}
	key := in.ObjectKey
	if !entity.ValidObjectKey(key) {
		return nil, errs.ErrInvalidArgument.WithMsg(i18n.T(reqctx.Lang(ctx), i18n.KeyUploadKeyInvalid, nil))
	}
	url, err := s.store.PresignGet(ctx, key, s.ttl)
	if err != nil {
		return nil, err
	}
	return &entity.Download{
		ObjectKey:   key,
		DownloadURL: url,
		Method:      entity.MethodGET,
		ExpiresIn:   s.expiresIn(),
	}, nil
}