package storage

import (
	"github.com/containers/image/copy"
	"github.com/containers/image/docker/reference"
	"github.com/containers/image/image"
	"github.com/containers/image/signature"
	istorage "github.com/containers/image/storage"
	"github.com/containers/image/transports/alltransports"
	"github.com/containers/image/types"
	"github.com/containers/storage"
)

// ImageResult wraps a subset of information about an image: its ID, its names,
// and the size, if known, or nil if it isn't.
type ImageResult struct {
	ID    string
	Names []string
	Size  *uint64
}

type imageService struct {
	store            storage.Store
	defaultTransport string
}

// ImageServer wraps up various CRI-related activities into a reusable
// implementation.
type ImageServer interface {
	// ListImages returns list of all images which match the filter.
	ListImages(filter string) ([]ImageResult, error)
	// ImageStatus returns status of an image which matches the filter.
	ImageStatus(systemContext *types.SystemContext, filter string) (*ImageResult, error)
	// PullImage imports an image from the specified location.
	PullImage(systemContext *types.SystemContext, imageName string, options *copy.Options) (types.ImageReference, error)
	// RemoveImage deletes the specified image.
	RemoveImage(systemContext *types.SystemContext, imageName string) error
	// GetStore returns the reference to the storage library Store which
	// the image server uses to hold images, and is the destination used
	// when it's asked to pull an image.
	GetStore() storage.Store
	// CanPull preliminary checks whether we're allowed to pull an image
	CanPull(imageName string, sourceCtx *types.SystemContext) (bool, error)
}

func (svc *imageService) ListImages(filter string) ([]ImageResult, error) {
	results := []ImageResult{}
	if filter != "" {
		ref, err := alltransports.ParseImageName(filter)
		if err != nil {
			ref2, err2 := istorage.Transport.ParseStoreReference(svc.store, "@"+filter)
			if err2 != nil {
				ref3, err3 := istorage.Transport.ParseStoreReference(svc.store, filter)
				if err3 != nil {
					return nil, err
				}
				ref2 = ref3
			}
			ref = ref2
		}
		if image, err := istorage.Transport.GetStoreImage(svc.store, ref); err == nil {
			results = append(results, ImageResult{
				ID:    image.ID,
				Names: image.Names,
			})
		}
	} else {
		images, err := svc.store.Images()
		if err != nil {
			return nil, err
		}
		for _, image := range images {
			results = append(results, ImageResult{
				ID:    image.ID,
				Names: image.Names,
			})
		}
	}
	return results, nil
}

func (svc *imageService) ImageStatus(systemContext *types.SystemContext, nameOrID string) (*ImageResult, error) {
	ref, err := alltransports.ParseImageName(nameOrID)
	if err != nil {
		ref2, err2 := istorage.Transport.ParseStoreReference(svc.store, "@"+nameOrID)
		if err2 != nil {
			ref3, err3 := istorage.Transport.ParseStoreReference(svc.store, nameOrID)
			if err3 != nil {
				return nil, err
			}
			ref2 = ref3
		}
		ref = ref2
	}
	image, err := istorage.Transport.GetStoreImage(svc.store, ref)
	if err != nil {
		return nil, err
	}

	img, err := ref.NewImage(systemContext)
	if err != nil {
		return nil, err
	}
	size := imageSize(img)
	img.Close()

	return &ImageResult{
		ID:    image.ID,
		Names: image.Names,
		Size:  size,
	}, nil
}

func imageSize(img types.Image) *uint64 {
	if sum, err := img.Size(); err == nil {
		usum := uint64(sum)
		return &usum
	}
	return nil
}

func (svc *imageService) CanPull(imageName string, sourceCtx *types.SystemContext) (bool, error) {
	if imageName == "" {
		return false, storage.ErrNotAnImage
	}
	srcRef, err := alltransports.ParseImageName(imageName)
	if err != nil {
		if svc.defaultTransport == "" {
			return false, err
		}
		srcRef2, err2 := alltransports.ParseImageName(svc.defaultTransport + imageName)
		if err2 != nil {
			return false, err
		}
		srcRef = srcRef2
	}
	rawSource, err := srcRef.NewImageSource(sourceCtx, nil)
	if err != nil {
		return false, err
	}
	unparsedImage := image.UnparsedFromSource(rawSource)
	defer unparsedImage.Close()
	src, err := image.FromUnparsedImage(unparsedImage)
	if err != nil {
		return false, err
	}
	src.Close()
	return true, nil
}

func (svc *imageService) PullImage(systemContext *types.SystemContext, imageName string, options *copy.Options) (types.ImageReference, error) {
	policy, err := signature.DefaultPolicy(systemContext)
	if err != nil {
		return nil, err
	}
	policyContext, err := signature.NewPolicyContext(policy)
	if err != nil {
		return nil, err
	}
	if imageName == "" {
		return nil, storage.ErrNotAnImage
	}
	if options == nil {
		options = &copy.Options{}
	}
	srcRef, err := alltransports.ParseImageName(imageName)
	if err != nil {
		if svc.defaultTransport == "" {
			return nil, err
		}
		srcRef2, err2 := alltransports.ParseImageName(svc.defaultTransport + imageName)
		if err2 != nil {
			return nil, err
		}
		srcRef = srcRef2
	}
	dest := imageName
	if srcRef.DockerReference() != nil {
		dest = srcRef.DockerReference().Name()
		if tagged, ok := srcRef.DockerReference().(reference.NamedTagged); ok {
			dest = dest + ":" + tagged.Tag()
		}
		if canonical, ok := srcRef.DockerReference().(reference.Canonical); ok {
			dest = dest + "@" + canonical.Digest().String()
		}
	}
	destRef, err := istorage.Transport.ParseStoreReference(svc.store, dest)
	if err != nil {
		return nil, err
	}
	err = copy.Image(policyContext, destRef, srcRef, options)
	if err != nil {
		return nil, err
	}
	return destRef, nil
}

func (svc *imageService) RemoveImage(systemContext *types.SystemContext, nameOrID string) error {
	ref, err := alltransports.ParseImageName(nameOrID)
	if err != nil {
		ref2, err2 := istorage.Transport.ParseStoreReference(svc.store, "@"+nameOrID)
		if err2 != nil {
			ref3, err3 := istorage.Transport.ParseStoreReference(svc.store, nameOrID)
			if err3 != nil {
				return err
			}
			ref2 = ref3
		}
		ref = ref2
	}
	return ref.DeleteImage(systemContext)
}

func (svc *imageService) GetStore() storage.Store {
	return svc.store
}

// GetImageService returns an ImageServer that uses the passed-in store, and
// which will prepend the passed-in defaultTransport value to an image name if
// a name that's passed to its PullImage() method can't be resolved to an image
// in the store and can't be resolved to a source on its own.
func GetImageService(store storage.Store, defaultTransport string) (ImageServer, error) {
	if store == nil {
		var err error
		store, err = storage.GetStore(storage.DefaultStoreOptions)
		if err != nil {
			return nil, err
		}
	}
	return &imageService{
		store:            store,
		defaultTransport: defaultTransport,
	}, nil
}