package image

import (
	"strings"

	"github.com/distribution/distribution/reference"
	"github.com/pkg/errors"
)

type ImageInfo struct {
	// Registry is the URL address of the image registry e.g. `docker.io`
	Registry string `json:"registry,omitempty"`

	// Name is the image name portion e.g. `busybox`
	Name string `json:"name"`

	// Path is the repository path and image name e.g. `some-repository/busybox`
	Path string `json:"path"`

	// Tag is the image tag e.g. `v2`
	Tag string `json:"tag,omitempty"`

	// Digest is the image digest portion e.g. `sha256:128c6e3534b842a2eec139999b8ce8aa9a2af9907e2b9269550809d18cd832a3`
	Digest string `json:"digest,omitempty"`
}

func (i *ImageInfo) String() string {
	image := i.Registry + "/" + i.Path
	if i.Digest != "" {
		return image + "@" + i.Digest
	} else {
		return image + ":" + i.Tag
	}
}

func GetImageInfo(image string) (*ImageInfo, error) {
	image = addDefaultDomain(image)
	ref, err := reference.Parse(image)
	if err != nil {
		return nil, errors.Wrapf(err, "bad image: %s", image)
	}
	var registry, path, name, tag, digest string
	if named, ok := ref.(reference.Named); ok {
		registry = reference.Domain(named)
		path = reference.Path(named)
		name = path[strings.LastIndex(path, "/")+1:]
	}
	if tagged, ok := ref.(reference.Tagged); ok {
		tag = tagged.Tag()
	}
	if digested, ok := ref.(reference.Digested); ok {
		digest = digested.Digest().String()
	}
	// set default tag - the domain is set via addDefaultDomain before parsing
	if digest == "" && tag == "" {
		tag = "latest"
	}
	return &ImageInfo{
		Registry: registry,
		Name:     name,
		Path:     path,
		Tag:      tag,
		Digest:   digest,
	}, nil
}

func addDefaultDomain(name string) string {
	i := strings.IndexRune(name, '/')
	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost" && strings.ToLower(name[:i]) == name[:i]) {
		return "docker.io/" + name
	}
	return name
}