type Descriptor struct {
	// MediaType is the media type of the object this schema refers to.
	MediaType string `json:"mediaType"`

	// Digest is the digest of the targeted content.
	Digest digest.Digest `json:"digest"`

	// Size specifies the size in bytes of the blob.
	Size int64 `json:"size"`

	// URLs specifies a list of URLs from which this object MAY be downloaded
	URLs []string `json:"urls,omitempty"`

	// Annotations contains arbitrary metadata relating to the targeted content.
	Annotations map[string]string `json:"annotations,omitempty"`

	// Data is an embedding of the targeted content. This is encoded as a base64
	// string when marshalled to JSON (automatically, by encoding/json). If
	// present, Data can be used directly to avoid fetching the targeted content.
	Data []byte `json:"data,omitempty"`

	// Platform describes the platform which the image in the manifest runs on.
	//
	// This should only be used when referring to a manifest.
	Platform *Platform `json:"platform,omitempty"`

	// ArtifactType is the IANA media type of this artifact.
	ArtifactType string `json:"artifactType,omitempty"`
}

type History struct {
	// Created is the combined date and time at which the layer was created, formatted as defined by RFC 3339, section 5.6.
	Created *time.Time `json:"created,omitempty"`

	// CreatedBy is the command which created the layer.
	CreatedBy string `json:"created_by,omitempty"`

	// Author is the author of the build point.
	Author string `json:"author,omitempty"`

	// Comment is a custom message set when creating the layer.
	Comment string `json:"comment,omitempty"`

	// EmptyLayer is used to mark if the history item created a filesystem diff.
	EmptyLayer bool `json:"empty_layer,omitempty"`
}

type Image struct {
	// Created is the combined date and time at which the image was created, formatted as defined by RFC 3339, section 5.6.
	Created *time.Time `json:"created,omitempty"`

	// Author defines the name and/or email address of the person or entity which created and is responsible for maintaining the image.
	Author string `json:"author,omitempty"`

	// Platform describes the platform which the image in the manifest runs on.
	Platform

	// Config defines the execution parameters which should be used as a base when running a container using the image.
	Config ImageConfig `json:"config,omitempty"`

	// RootFS references the layer content addresses used by the image.
	RootFS RootFS `json:"rootfs"`

	// History describes the history of each layer.
	History []History `json:"history,omitempty"`
}

type ImageConfig struct {
	// User defines the username or UID which the process in the container should run as.
	User string `json:"User,omitempty"`

	// ExposedPorts a set of ports to expose from a container running this image.
	ExposedPorts map[string]struct{} `json:"ExposedPorts,omitempty"`

	// Env is a list of environment variables to be used in a container.
	Env []string `json:"Env,omitempty"`

	// Entrypoint defines a list of arguments to use as the command to execute when the container starts.
	Entrypoint []string `json:"Entrypoint,omitempty"`

	// Cmd defines the default arguments to the entrypoint of the container.
	Cmd []string `json:"Cmd,omitempty"`

	// Volumes is a set of directories describing where the process is likely write data specific to a container instance.
	Volumes map[string]struct{} `json:"Volumes,omitempty"`

	// WorkingDir sets the current working directory of the entrypoint process in the container.
	WorkingDir string `json:"WorkingDir,omitempty"`

	// Labels contains arbitrary metadata for the container.
	Labels map[string]string `json:"Labels,omitempty"`

	// StopSignal contains the system call signal that will be sent to the container to exit.
	StopSignal string `json:"StopSignal,omitempty"`

	// ArgsEscaped
	//
	// Deprecated: This field is present only for legacy compatibility with
	// Docker and should not be used by new image builders.  It is used by Docker
	// for Windows images to indicate that the `Entrypoint` or `Cmd` or both,
	// contains only a single element array, that is a pre-escaped, and combined
	// into a single string `CommandLine`. If `true` the value in `Entrypoint` or
	// `Cmd` should be used as-is to avoid double escaping.
	// https://github.com/opencontainers/image-spec/pull/892
	ArgsEscaped bool `json:"ArgsEscaped,omitempty"`
}

type ImageLayout struct {
	Version string `json:"imageLayoutVersion"`
}

type Index struct {
	specs.Versioned

	// MediaType specifies the type of this document data structure e.g. `application/vnd.oci.image.index.v1+json`
	MediaType string `json:"mediaType,omitempty"`

	// ArtifactType specifies the IANA media type of artifact when the manifest is used for an artifact.
	ArtifactType string `json:"artifactType,omitempty"`

	// Manifests references platform specific manifests.
	Manifests []Descriptor `json:"manifests"`

	// Subject is an optional link from the image manifest to another manifest forming an association between the image manifest and the other manifest.
	Subject *Descriptor `json:"subject,omitempty"`

	// Annotations contains arbitrary metadata for the image index.
	Annotations map[string]string `json:"annotations,omitempty"`
}

type Manifest struct {
	specs.Versioned

	// MediaType specifies the type of this document data structure e.g. `application/vnd.oci.image.manifest.v1+json`
	MediaType string `json:"mediaType,omitempty"`

	// ArtifactType specifies the IANA media type of artifact when the manifest is used for an artifact.
	ArtifactType string `json:"artifactType,omitempty"`

	// Config references a configuration object for a container, by digest.
	// The referenced configuration object is a JSON blob that the runtime uses to set up the container.
	Config Descriptor `json:"config"`

	// Layers is an indexed list of layers referenced by the manifest.
	Layers []Descriptor `json:"layers"`

	// Subject is an optional link from the image manifest to another manifest forming an association between the image manifest and the other manifest.
	Subject *Descriptor `json:"subject,omitempty"`

	// Annotations contains arbitrary metadata for the image manifest.
	Annotations map[string]string `json:"annotations,omitempty"`
}

type Platform struct {
	// Architecture field specifies the CPU architecture, for example
	// `amd64` or `ppc64le`.
	Architecture string `json:"architecture"`

	// OS specifies the operating system, for example `linux` or `windows`.
	OS string `json:"os"`

	// OSVersion is an optional field specifying the operating system
	// version, for example on Windows `10.0.14393.1066`.
	OSVersion string `json:"os.version,omitempty"`

	// OSFeatures is an optional field specifying an array of strings,
	// each listing a required OS feature (for example on Windows `win32k`).
	OSFeatures []string `json:"os.features,omitempty"`

	// Variant is an optional field specifying a variant of the CPU, for
	// example `v7` to specify ARMv7 when architecture is `arm`.
	Variant string `json:"variant,omitempty"`
}

type RootFS struct {
	// Type is the type of the rootfs.
	Type string `json:"type"`

	// DiffIDs is an array of layer content hashes (DiffIDs), in order from bottom-most to top-most.
	DiffIDs []digest.Digest `json:"diff_ids"`
}