package v2

import (
	"net/http"
	"regexp"

	"github.com/docker/distribution/digest"
)

var (
	nameParameterDescriptor = ParameterDescriptor{
		Name:        "name",
		Type:        "string",
		Format:      RepositoryNameRegexp.String(),
		Required:    true,
		Description: `Name of the target repository.`,
	}

	tagParameterDescriptor = ParameterDescriptor{
		Name:        "tag",
		Type:        "string",
		Format:      TagNameRegexp.String(),
		Required:    true,
		Description: `Tag of the target manifiest.`,
	}

	uuidParameterDescriptor = ParameterDescriptor{
		Name:        "uuid",
		Type:        "opaque",
		Required:    true,
		Description: "A uuid identifying the upload. This field can accept characters that match `[a-zA-Z0-9-_.=]+`.",
	}

	digestPathParameter = ParameterDescriptor{
		Name:        "digest",
		Type:        "path",
		Required:    true,
		Format:      digest.DigestRegexp.String(),
		Description: `Digest of desired blob.`,
	}

	hostHeader = ParameterDescriptor{
		Name:        "Host",
		Type:        "string",
		Description: "Standard HTTP Host Header. Should be set to the registry host.",
		Format:      "<registry host>",
		Examples:    []string{"registry-1.docker.io"},
	}

	authHeader = ParameterDescriptor{
		Name:        "Authorization",
		Type:        "string",
		Description: "An RFC7235 compliant authorization header.",
		Format:      "<scheme> <token>",
		Examples:    []string{"Bearer dGhpcyBpcyBhIGZha2UgYmVhcmVyIHRva2VuIQ=="},
	}

	authChallengeHeader = ParameterDescriptor{
		Name:        "WWW-Authenticate",
		Type:        "string",
		Description: "An RFC7235 compliant authentication challenge header.",
		Format:      `<scheme> realm="<realm>", ..."`,
		Examples: []string{
			`Bearer realm="https://auth.docker.com/", service="registry.docker.com", scopes="repository:library/ubuntu:pull"`,
		},
	}

	contentLengthZeroHeader = ParameterDescriptor{
		Name:        "Content-Length",
		Description: "The `Content-Length` header must be zero and the body must be empty.",
		Type:        "integer",
		Format:      "0",
	}

	dockerUploadUUIDHeader = ParameterDescriptor{
		Name:        "Docker-Upload-UUID",
		Description: "Identifies the docker upload uuid for the current request.",
		Type:        "uuid",
		Format:      "<uuid>",
	}

	digestHeader = ParameterDescriptor{
		Name:        "Docker-Content-Digest",
		Description: "Digest of the targeted content for the request.",
		Type:        "digest",
		Format:      "<digest>",
	}

	unauthorizedResponse = ResponseDescriptor{
		Description: "The client does not have access to the repository.",
		StatusCode:  http.StatusUnauthorized,
		Headers: []ParameterDescriptor{
			authChallengeHeader,
			{
				Name:        "Content-Length",
				Type:        "integer",
				Description: "Length of the JSON error response body.",
				Format:      "<length>",
			},
		},
		ErrorCodes: []ErrorCode{
			ErrorCodeUnauthorized,
		},
		Body: BodyDescriptor{
			ContentType: "application/json; charset=utf-8",
			Format:      unauthorizedErrorsBody,
		},
	}

	unauthorizedResponsePush = ResponseDescriptor{
		Description: "The client does not have access to push to the repository.",
		StatusCode:  http.StatusUnauthorized,
		Headers: []ParameterDescriptor{
			authChallengeHeader,
			{
				Name:        "Content-Length",
				Type:        "integer",
				Description: "Length of the JSON error response body.",
				Format:      "<length>",
			},
		},
		ErrorCodes: []ErrorCode{
			ErrorCodeUnauthorized,
		},
		Body: BodyDescriptor{
			ContentType: "application/json; charset=utf-8",
			Format:      unauthorizedErrorsBody,
		},
	}
)

const (
	manifestBody = `{
   "name": <name>,
   "tag": <tag>,
   "fsLayers": [
      {
         "blobSum": <tarsum>
      },
      ...
    ]
   ],
   "history": <v1 images>,
   "signature": <JWS>
}`

	errorsBody = `{
	"errors:" [
	    {
            "code": <error code>,
            "message": "<error message>",
            "detail": ...
        },
        ...
    ]
}`

	unauthorizedErrorsBody = `{
	"errors:" [
	    {
            "code": "UNAUTHORIZED",
            "message": "access to the requested resource is not authorized",
            "detail": ...
        },
        ...
    ]
}`
)

// APIDescriptor exports descriptions of the layout of the v2 registry API.
var APIDescriptor = struct {
	// RouteDescriptors provides a list of the routes available in the API.
	RouteDescriptors []RouteDescriptor

	// ErrorDescriptors provides a list of the error codes and their
	// associated documentation and metadata.
	ErrorDescriptors []ErrorDescriptor
}{
	RouteDescriptors: routeDescriptors,
	ErrorDescriptors: errorDescriptors,
}

// RouteDescriptor describes a route specified by name.
type RouteDescriptor struct {
	// Name is the name of the route, as specified in RouteNameXXX exports.
	// These names a should be considered a unique reference for a route. If
	// the route is registered with gorilla, this is the name that will be
	// used.
	Name string

	// Path is a gorilla/mux-compatible regexp that can be used to match the
	// route. For any incoming method and path, only one route descriptor
	// should match.
	Path string

	// Entity should be a short, human-readalbe description of the object
	// targeted by the endpoint.
	Entity string

	// Description should provide an accurate overview of the functionality
	// provided by the route.
	Description string

	// Methods should describe the various HTTP methods that may be used on
	// this route, including request and response formats.
	Methods []MethodDescriptor
}

// MethodDescriptor provides a description of the requests that may be
// conducted with the target method.
type MethodDescriptor struct {

	// Method is an HTTP method, such as GET, PUT or POST.
	Method string

	// Description should provide an overview of the functionality provided by
	// the covered method, suitable for use in documentation. Use of markdown
	// here is encouraged.
	Description string

	// Requests is a slice of request descriptors enumerating how this
	// endpoint may be used.
	Requests []RequestDescriptor
}

// RequestDescriptor covers a particular set of headers and parameters that
// can be carried out with the parent method. Its most helpful to have one
// RequestDescriptor per API use case.
type RequestDescriptor struct {
	// Name provides a short identifier for the request, usable as a title or
	// to provide quick context for the particalar request.
	Name string

	// Description should cover the requests purpose, covering any details for
	// this particular use case.
	Description string

	// Headers describes headers that must be used with the HTTP request.
	Headers []ParameterDescriptor

	// PathParameters enumerate the parameterized path components for the
	// given request, as defined in the route's regular expression.
	PathParameters []ParameterDescriptor

	// QueryParameters provides a list of query parameters for the given
	// request.
	QueryParameters []ParameterDescriptor

	// Body describes the format of the request body.
	Body BodyDescriptor

	// Successes enumerates the possible responses that are considered to be
	// the result of a successful request.
	Successes []ResponseDescriptor

	// Failures covers the possible failures from this particular request.
	Failures []ResponseDescriptor
}

// ResponseDescriptor describes the components of an API response.
type ResponseDescriptor struct {
	// Name provides a short identifier for the response, usable as a title or
	// to provide quick context for the particalar response.
	Name string

	// Description should provide a brief overview of the role of the
	// response.
	Description string

	// StatusCode specifies the status recieved by this particular response.
	StatusCode int

	// Headers covers any headers that may be returned from the response.
	Headers []ParameterDescriptor

	// ErrorCodes enumerates the error codes that may be returned along with
	// the response.
	ErrorCodes []ErrorCode

	// Body describes the body of the response, if any.
	Body BodyDescriptor
}

// BodyDescriptor describes a request body and its expected content type. For
// the most  part, it should be example json or some placeholder for body
// data in documentation.
type BodyDescriptor struct {
	ContentType string
	Format      string
}

// ParameterDescriptor describes the format of a request parameter, which may
// be a header, path parameter or query parameter.
type ParameterDescriptor struct {
	// Name is the name of the parameter, either of the path component or
	// query parameter.
	Name string

	// Type specifies the type of the parameter, such as string, integer, etc.
	Type string

	// Description provides a human-readable description of the parameter.
	Description string

	// Required means the field is required when set.
	Required bool

	// Format is a specifying the string format accepted by this parameter.
	Format string

	// Regexp is a compiled regular expression that can be used to validate
	// the contents of the parameter.
	Regexp *regexp.Regexp

	// Examples provides multiple examples for the values that might be valid
	// for this parameter.
	Examples []string
}

// ErrorDescriptor provides relevant information about a given error code.
type ErrorDescriptor struct {
	// Code is the error code that this descriptor describes.
	Code ErrorCode

	// Value provides a unique, string key, often captilized with
	// underscores, to identify the error code. This value is used as the
	// keyed value when serializing api errors.
	Value string

	// Message is a short, human readable decription of the error condition
	// included in API responses.
	Message string

	// Description provides a complete account of the errors purpose, suitable
	// for use in documentation.
	Description string

	// HTTPStatusCodes provides a list of status under which this error
	// condition may arise. If it is empty, the error condition may be seen
	// for any status code.
	HTTPStatusCodes []int
}

var routeDescriptors = []RouteDescriptor{
	{
		Name:        RouteNameBase,
		Path:        "/v2/",
		Entity:      "Base",
		Description: `Base V2 API route. Typically, this can be used for lightweight version checks and to validate registry authorization.`,
		Methods: []MethodDescriptor{
			{
				Method:      "GET",
				Description: "Check that the endpoint implements Docker Registry API V2.",
				Requests: []RequestDescriptor{
					{
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The API implements V2 protocol and is accessible.",
								StatusCode:  http.StatusOK,
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "The client is not authorized to access the registry.",
								StatusCode:  http.StatusUnauthorized,
								Headers: []ParameterDescriptor{
									authChallengeHeader,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
							},
							{
								Description: "The registry does not implement the V2 API.",
								StatusCode:  http.StatusNotFound,
							},
						},
					},
				},
			},
		},
	},
	{
		Name:        RouteNameTags,
		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/tags/list",
		Entity:      "Tags",
		Description: "Retrieve information about tags.",
		Methods: []MethodDescriptor{
			{
				Method:      "GET",
				Description: "Fetch the tags under the repository identified by `name`.",
				Requests: []RequestDescriptor{
					{
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
						},
						Successes: []ResponseDescriptor{
							{
								StatusCode:  http.StatusOK,
								Description: "A list of tags for the named repository.",
								Headers: []ParameterDescriptor{
									{
										Name:        "Content-Length",
										Type:        "integer",
										Description: "Length of the JSON response body.",
										Format:      "<length>",
									},
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format: `{
    "name": <name>,
    "tags": [
        <tag>,
        ...
    ]
}`,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								StatusCode:  http.StatusNotFound,
								Description: "The repository is not known to the registry.",
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeNameUnknown,
								},
							},
							{
								StatusCode:  http.StatusUnauthorized,
								Description: "The client does not have access to the repository.",
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
							},
						},
					},
				},
			},
		},
	},
	{
		Name:        RouteNameManifest,
		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/manifests/{reference:" + TagNameRegexp.String() + "|" + digest.DigestRegexp.String() + "}",
		Entity:      "Manifest",
		Description: "Create, update and retrieve manifests.",
		Methods: []MethodDescriptor{
			{
				Method:      "GET",
				Description: "Fetch the manifest identified by `name` and `reference` where `reference` can be a tag or digest.",
				Requests: []RequestDescriptor{
					{
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							tagParameterDescriptor,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The manifest idenfied by `name` and `reference`. The contents can be used to identify and resolve resources required to run the specified image.",
								StatusCode:  http.StatusOK,
								Headers: []ParameterDescriptor{
									digestHeader,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      manifestBody,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "The name or reference was invalid.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeTagInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								StatusCode:  http.StatusUnauthorized,
								Description: "The client does not have access to the repository.",
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
							},
							{
								Description: "The named manifest is not known to the registry.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameUnknown,
									ErrorCodeManifestUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
						},
					},
				},
			},
			{
				Method:      "PUT",
				Description: "Put the manifest identified by `name` and `reference` where `reference` can be a tag or digest.",
				Requests: []RequestDescriptor{
					{
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							tagParameterDescriptor,
						},
						Body: BodyDescriptor{
							ContentType: "application/json; charset=utf-8",
							Format:      manifestBody,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The manifest has been accepted by the registry and is stored under the specified `name` and `tag`.",
								StatusCode:  http.StatusAccepted,
								Headers: []ParameterDescriptor{
									{
										Name:        "Location",
										Type:        "url",
										Description: "The canonical location url of the uploaded manifest.",
										Format:      "<url>",
									},
									contentLengthZeroHeader,
									digestHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Name:        "Invalid Manifest",
								Description: "The received manifest was invalid in some way, as described by the error codes. The client should resolve the issue and retry the request.",
								StatusCode:  http.StatusBadRequest,
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeTagInvalid,
									ErrorCodeManifestInvalid,
									ErrorCodeManifestUnverified,
									ErrorCodeBlobUnknown,
								},
							},
							{
								StatusCode:  http.StatusUnauthorized,
								Description: "The client does not have permission to push to the repository.",
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
							},
							{
								Name:        "Missing Layer(s)",
								Description: "One or more layers may be missing during a manifest upload. If so, the missing layers will be enumerated in the error response.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeBlobUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format: `{
    "errors:" [{
            "code": "BLOB_UNKNOWN",
            "message": "blob unknown to registry",
            "detail": {
                "digest": <tarsum>
            }
        },
        ...
    ]
}`,
								},
							},
							{
								StatusCode: http.StatusUnauthorized,
								Headers: []ParameterDescriptor{
									authChallengeHeader,
									{
										Name:        "Content-Length",
										Type:        "integer",
										Description: "Length of the JSON error response body.",
										Format:      "<length>",
									},
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
						},
					},
				},
			},
			{
				Method:      "DELETE",
				Description: "Delete the manifest identified by `name` and `reference` where `reference` can be a tag or digest.",
				Requests: []RequestDescriptor{
					{
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							tagParameterDescriptor,
						},
						Successes: []ResponseDescriptor{
							{
								StatusCode: http.StatusAccepted,
							},
						},
						Failures: []ResponseDescriptor{
							{
								Name:        "Invalid Name or Tag",
								Description: "The specified `name` or `tag` were invalid and the delete was unable to proceed.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeTagInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								StatusCode: http.StatusUnauthorized,
								Headers: []ParameterDescriptor{
									authChallengeHeader,
									{
										Name:        "Content-Length",
										Type:        "integer",
										Description: "Length of the JSON error response body.",
										Format:      "<length>",
									},
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeUnauthorized,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								Name:        "Unknown Manifest",
								Description: "The specified `name` or `tag` are unknown to the registry and the delete was unable to proceed. Clients can assume the manifest was already deleted if this response is returned.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameUnknown,
									ErrorCodeManifestUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
						},
					},
				},
			},
		},
	},

	{
		Name:        RouteNameBlob,
		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/{digest:" + digest.DigestRegexp.String() + "}",
		Entity:      "Blob",
		Description: "Fetch the blob identified by `name` and `digest`. Used to fetch layers by tarsum digest.",
		Methods: []MethodDescriptor{

			{
				Method:      "GET",
				Description: "Retrieve the blob from the registry identified by `digest`. A `HEAD` request can also be issued to this endpoint to obtain resource information without receiving all data.",
				Requests: []RequestDescriptor{
					{
						Name: "Fetch Blob",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							digestPathParameter,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The blob identified by `digest` is available. The blob content will be present in the body of the request.",
								StatusCode:  http.StatusOK,
								Headers: []ParameterDescriptor{
									{
										Name:        "Content-Length",
										Type:        "integer",
										Description: "The length of the requested blob content.",
										Format:      "<length>",
									},
									digestHeader,
								},
								Body: BodyDescriptor{
									ContentType: "application/octet-stream",
									Format:      "<blob binary data>",
								},
							},
							{
								Description: "The blob identified by `digest` is available at the provided location.",
								StatusCode:  http.StatusTemporaryRedirect,
								Headers: []ParameterDescriptor{
									{
										Name:        "Location",
										Type:        "url",
										Description: "The location where the layer should be accessible.",
										Format:      "<blob location>",
									},
									digestHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "There was a problem with the request that needs to be addressed by the client, such as an invalid `name` or `tag`.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeDigestInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponse,
							{
								Description: "The blob, identified by `name` and `digest`, is unknown to the registry.",
								StatusCode:  http.StatusNotFound,
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
								ErrorCodes: []ErrorCode{
									ErrorCodeNameUnknown,
									ErrorCodeBlobUnknown,
								},
							},
						},
					},
					{
						Name:        "Fetch Blob Part",
						Description: "This endpoint may also support RFC7233 compliant range requests. Support can be detected by issuing a HEAD request. If the header `Accept-Range: bytes` is returned, range requests can be used to fetch partial content.",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							{
								Name:        "Range",
								Type:        "string",
								Description: "HTTP Range header specifying blob chunk.",
								Format:      "bytes=<start>-<end>",
							},
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							digestPathParameter,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The blob identified by `digest` is available. The specified chunk of blob content will be present in the body of the request.",
								StatusCode:  http.StatusPartialContent,
								Headers: []ParameterDescriptor{
									{
										Name:        "Content-Length",
										Type:        "integer",
										Description: "The length of the requested blob chunk.",
										Format:      "<length>",
									},
									{
										Name:        "Content-Range",
										Type:        "byte range",
										Description: "Content range of blob chunk.",
										Format:      "bytes <start>-<end>/<size>",
									},
								},
								Body: BodyDescriptor{
									ContentType: "application/octet-stream",
									Format:      "<blob binary data>",
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "There was a problem with the request that needs to be addressed by the client, such as an invalid `name` or `tag`.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeDigestInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponse,
							{
								StatusCode: http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameUnknown,
									ErrorCodeBlobUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								Description: "The range specification cannot be satisfied for the requested content. This can happen when the range is not formatted correctly or if the range is outside of the valid size of the content.",
								StatusCode:  http.StatusRequestedRangeNotSatisfiable,
							},
						},
					},
				},
			},
			// TODO(stevvooe): We may want to add a PUT request here to
			// kickoff an upload of a blob, integrated with the blob upload
			// API.
		},
	},

	{
		Name:        RouteNameBlobUpload,
		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/uploads/",
		Entity:      "Intiate Blob Upload",
		Description: "Initiate a blob upload. This endpoint can be used to create resumable uploads or monolithic uploads.",
		Methods: []MethodDescriptor{
			{
				Method:      "POST",
				Description: "Initiate a resumable blob upload. If successful, an upload location will be provided to complete the upload. Optionally, if the `digest` parameter is present, the request body will be used to complete the upload in a single request.",
				Requests: []RequestDescriptor{
					{
						Name:        "Initiate Monolithic Blob Upload",
						Description: "Upload a blob identified by the `digest` parameter in single request. This upload will not be resumable unless a recoverable error is returned.",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							{
								Name:   "Content-Length",
								Type:   "integer",
								Format: "<length of blob>",
							},
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
						},
						QueryParameters: []ParameterDescriptor{
							{
								Name:        "digest",
								Type:        "query",
								Format:      "<tarsum>",
								Regexp:      digest.DigestRegexp,
								Description: `Digest of uploaded blob. If present, the upload will be completed, in a single request, with contents of the request body as the resulting blob.`,
							},
						},
						Body: BodyDescriptor{
							ContentType: "application/octect-stream",
							Format:      "<binary data>",
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The blob has been created in the registry and is available at the provided location.",
								StatusCode:  http.StatusCreated,
								Headers: []ParameterDescriptor{
									{
										Name:   "Location",
										Type:   "url",
										Format: "<blob location>",
									},
									contentLengthZeroHeader,
									dockerUploadUUIDHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Name:       "Invalid Name or Digest",
								StatusCode: http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeDigestInvalid,
									ErrorCodeNameInvalid,
								},
							},
							unauthorizedResponsePush,
						},
					},
					{
						Name:        "Initiate Resumable Blob Upload",
						Description: "Initiate a resumable blob upload with an empty request body.",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							contentLengthZeroHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
						},
						Successes: []ResponseDescriptor{
							{
								Description: "The upload has been created. The `Location` header must be used to complete the upload. The response should be identical to a `GET` request on the contents of the returned `Location` header.",
								StatusCode:  http.StatusAccepted,
								Headers: []ParameterDescriptor{
									contentLengthZeroHeader,
									{
										Name:        "Location",
										Type:        "url",
										Format:      "/v2/<name>/blobs/uploads/<uuid>",
										Description: "The location of the created upload. Clients should use the contents verbatim to complete the upload, adding parameters where required.",
									},
									{
										Name:        "Range",
										Format:      "0-0",
										Description: "Range header indicating the progress of the upload. When starting an upload, it will return an empty range, since no content has been received.",
									},
									dockerUploadUUIDHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Name:       "Invalid Name or Digest",
								StatusCode: http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeDigestInvalid,
									ErrorCodeNameInvalid,
								},
							},
							unauthorizedResponsePush,
						},
					},
				},
			},
		},
	},

	{
		Name:        RouteNameBlobUploadChunk,
		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/uploads/{uuid:[a-zA-Z0-9-_.=]+}",
		Entity:      "Blob Upload",
		Description: "Interact with blob uploads. Clients should never assemble URLs for this endpoint and should only take it through the `Location` header on related API requests. The `Location` header and its parameters should be preserved by clients, using the latest value returned via upload related API calls.",
		Methods: []MethodDescriptor{
			{
				Method:      "GET",
				Description: "Retrieve status of upload identified by `uuid`. The primary purpose of this endpoint is to resolve the current status of a resumable upload.",
				Requests: []RequestDescriptor{
					{
						Description: "Retrieve the progress of the current upload, as reported by the `Range` header.",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							uuidParameterDescriptor,
						},
						Successes: []ResponseDescriptor{
							{
								Name:        "Upload Progress",
								Description: "The upload is known and in progress. The last received offset is available in the `Range` header.",
								StatusCode:  http.StatusNoContent,
								Headers: []ParameterDescriptor{
									{
										Name:        "Range",
										Type:        "header",
										Format:      "0-<offset>",
										Description: "Range indicating the current progress of the upload.",
									},
									contentLengthZeroHeader,
									dockerUploadUUIDHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "There was an error processing the upload and it must be restarted.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeDigestInvalid,
									ErrorCodeNameInvalid,
									ErrorCodeBlobUploadInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponse,
							{
								Description: "The upload is unknown to the registry. The upload must be restarted.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeBlobUploadUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
						},
					},
				},
			},
			{
				Method:      "PATCH",
				Description: "Upload a chunk of data for the specified upload.",
				Requests: []RequestDescriptor{
					{
						Description: "Upload a chunk of data to specified upload without completing the upload.",
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							uuidParameterDescriptor,
						},
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							{
								Name:        "Content-Range",
								Type:        "header",
								Format:      "<start of range>-<end of range, inclusive>",
								Required:    true,
								Description: "Range of bytes identifying the desired block of content represented by the body. Start must the end offset retrieved via status check plus one. Note that this is a non-standard use of the `Content-Range` header.",
							},
							{
								Name:        "Content-Length",
								Type:        "integer",
								Format:      "<length of chunk>",
								Description: "Length of the chunk being uploaded, corresponding the length of the request body.",
							},
						},
						Body: BodyDescriptor{
							ContentType: "application/octet-stream",
							Format:      "<binary chunk>",
						},
						Successes: []ResponseDescriptor{
							{
								Name:        "Chunk Accepted",
								Description: "The chunk of data has been accepted and the current progress is available in the range header. The updated upload location is available in the `Location` header.",
								StatusCode:  http.StatusNoContent,
								Headers: []ParameterDescriptor{
									{
										Name:        "Location",
										Type:        "url",
										Format:      "/v2/<name>/blobs/uploads/<uuid>",
										Description: "The location of the upload. Clients should assume this changes after each request. Clients should use the contents verbatim to complete the upload, adding parameters where required.",
									},
									{
										Name:        "Range",
										Type:        "header",
										Format:      "0-<offset>",
										Description: "Range indicating the current progress of the upload.",
									},
									contentLengthZeroHeader,
									dockerUploadUUIDHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "There was an error processing the upload and it must be restarted.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeDigestInvalid,
									ErrorCodeNameInvalid,
									ErrorCodeBlobUploadInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponsePush,
							{
								Description: "The upload is unknown to the registry. The upload must be restarted.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeBlobUploadUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								Description: "The `Content-Range` specification cannot be accepted, either because it does not overlap with the current progress or it is invalid.",
								StatusCode:  http.StatusRequestedRangeNotSatisfiable,
							},
						},
					},
				},
			},
			{
				Method:      "PUT",
				Description: "Complete the upload specified by `uuid`, optionally appending the body as the final chunk.",
				Requests: []RequestDescriptor{
					{
						// TODO(stevvooe): Break this down into three separate requests:
						// 	1. Complete an upload where all data has already been sent.
						// 	2. Complete an upload where the entire body is in the PUT.
						// 	3. Complete an upload where the final, partial chunk is the body.

						Description: "Complete the upload, providing the _final_ chunk of data, if necessary. This method may take a body with all the data. If the `Content-Range` header is specified, it may include the final chunk. A request without a body will just complete the upload with previously uploaded content.",
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							{
								Name:        "Content-Range",
								Type:        "header",
								Format:      "<start of range>-<end of range, inclusive>",
								Description: "Range of bytes identifying the block of content represented by the body. Start must the end offset retrieved via status check plus one. Note that this is a non-standard use of the `Content-Range` header. May be omitted if no data is provided.",
							},
							{
								Name:        "Content-Length",
								Type:        "integer",
								Format:      "<length of chunk>",
								Description: "Length of the chunk being uploaded, corresponding to the length of the request body. May be zero if no data is provided.",
							},
						},
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							uuidParameterDescriptor,
						},
						QueryParameters: []ParameterDescriptor{
							{
								Name:        "digest",
								Type:        "string",
								Format:      "<tarsum>",
								Regexp:      digest.DigestRegexp,
								Required:    true,
								Description: `Digest of uploaded blob.`,
							},
						},
						Body: BodyDescriptor{
							ContentType: "application/octet-stream",
							Format:      "<binary chunk>",
						},
						Successes: []ResponseDescriptor{
							{
								Name:        "Upload Complete",
								Description: "The upload has been completed and accepted by the registry. The canonical location will be available in the `Location` header.",
								StatusCode:  http.StatusNoContent,
								Headers: []ParameterDescriptor{
									{
										Name:   "Location",
										Type:   "url",
										Format: "<blob location>",
									},
									{
										Name:        "Content-Range",
										Type:        "header",
										Format:      "<start of range>-<end of range, inclusive>",
										Description: "Range of bytes identifying the desired block of content represented by the body. Start must match the end of offset retrieved via status check. Note that this is a non-standard use of the `Content-Range` header.",
									},
									{
										Name:        "Content-Length",
										Type:        "integer",
										Format:      "<length of chunk>",
										Description: "Length of the chunk being uploaded, corresponding the length of the request body.",
									},
									digestHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "There was an error processing the upload and it must be restarted.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeDigestInvalid,
									ErrorCodeNameInvalid,
									ErrorCodeBlobUploadInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponsePush,
							{
								Description: "The upload is unknown to the registry. The upload must be restarted.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeBlobUploadUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							{
								Description: "The `Content-Range` specification cannot be accepted, either because it does not overlap with the current progress or it is invalid. The contents of the `Range` header may be used to resolve the condition.",
								StatusCode:  http.StatusRequestedRangeNotSatisfiable,
								Headers: []ParameterDescriptor{
									{
										Name:        "Location",
										Type:        "url",
										Format:      "/v2/<name>/blobs/uploads/<uuid>",
										Description: "The location of the upload. Clients should assume this changes after each request. Clients should use the contents verbatim to complete the upload, adding parameters where required.",
									},
									{
										Name:        "Range",
										Type:        "header",
										Format:      "0-<offset>",
										Description: "Range indicating the current progress of the upload.",
									},
								},
							},
						},
					},
				},
			},
			{
				Method:      "DELETE",
				Description: "Cancel outstanding upload processes, releasing associated resources. If this is not called, the unfinished uploads will eventually timeout.",
				Requests: []RequestDescriptor{
					{
						Description: "Cancel the upload specified by `uuid`.",
						PathParameters: []ParameterDescriptor{
							nameParameterDescriptor,
							uuidParameterDescriptor,
						},
						Headers: []ParameterDescriptor{
							hostHeader,
							authHeader,
							contentLengthZeroHeader,
						},
						Successes: []ResponseDescriptor{
							{
								Name:        "Upload Deleted",
								Description: "The upload has been successfully deleted.",
								StatusCode:  http.StatusNoContent,
								Headers: []ParameterDescriptor{
									contentLengthZeroHeader,
								},
							},
						},
						Failures: []ResponseDescriptor{
							{
								Description: "An error was encountered processing the delete. The client may ignore this error.",
								StatusCode:  http.StatusBadRequest,
								ErrorCodes: []ErrorCode{
									ErrorCodeNameInvalid,
									ErrorCodeBlobUploadInvalid,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
							unauthorizedResponse,
							{
								Description: "The upload is unknown to the registry. The client may ignore this error and assume the upload has been deleted.",
								StatusCode:  http.StatusNotFound,
								ErrorCodes: []ErrorCode{
									ErrorCodeBlobUploadUnknown,
								},
								Body: BodyDescriptor{
									ContentType: "application/json; charset=utf-8",
									Format:      errorsBody,
								},
							},
						},
					},
				},
			},
		},
	},
}

// ErrorDescriptors provides a list of HTTP API Error codes that may be
// encountered when interacting with the registry API.
var errorDescriptors = []ErrorDescriptor{
	{
		Code:    ErrorCodeUnknown,
		Value:   "UNKNOWN",
		Message: "unknown error",
		Description: `Generic error returned when the error does not have an
		API classification.`,
	},
	{
		Code:    ErrorCodeUnsupported,
		Value:   "UNSUPPORTED",
		Message: "The operation is unsupported.",
		Description: `The operation was unsupported due to a missing
		implementation or invalid set of parameters.`,
	},
	{
		Code:    ErrorCodeUnauthorized,
		Value:   "UNAUTHORIZED",
		Message: "access to the requested resource is not authorized",
		Description: `The access controller denied access for the operation on
		a resource. Often this will be accompanied by a 401 Unauthorized
		response status.`,
	},
	{
		Code:    ErrorCodeDigestInvalid,
		Value:   "DIGEST_INVALID",
		Message: "provided digest did not match uploaded content",
		Description: `When a blob is uploaded, the registry will check that
		the content matches the digest provided by the client. The error may
		include a detail structure with the key "digest", including the
		invalid digest string. This error may also be returned when a manifest
		includes an invalid layer digest.`,
		HTTPStatusCodes: []int{http.StatusBadRequest, http.StatusNotFound},
	},
	{
		Code:    ErrorCodeSizeInvalid,
		Value:   "SIZE_INVALID",
		Message: "provided length did not match content length",
		Description: `When a layer is uploaded, the provided size will be
		checked against the uploaded content. If they do not match, this error
		will be returned.`,
		HTTPStatusCodes: []int{http.StatusBadRequest},
	},
	{
		Code:    ErrorCodeNameInvalid,
		Value:   "NAME_INVALID",
		Message: "invalid repository name",
		Description: `Invalid repository name encountered either during
		manifest validation or any API operation.`,
		HTTPStatusCodes: []int{http.StatusBadRequest, http.StatusNotFound},
	},
	{
		Code:    ErrorCodeTagInvalid,
		Value:   "TAG_INVALID",
		Message: "manifest tag did not match URI",
		Description: `During a manifest upload, if the tag in the manifest
		does not match the uri tag, this error will be returned.`,
		HTTPStatusCodes: []int{http.StatusBadRequest, http.StatusNotFound},
	},
	{
		Code:    ErrorCodeNameUnknown,
		Value:   "NAME_UNKNOWN",
		Message: "repository name not known to registry",
		Description: `This is returned if the name used during an operation is
		unknown to the registry.`,
		HTTPStatusCodes: []int{http.StatusNotFound},
	},
	{
		Code:    ErrorCodeManifestUnknown,
		Value:   "MANIFEST_UNKNOWN",
		Message: "manifest unknown",
		Description: `This error is returned when the manifest, identified by
		name and tag is unknown to the repository.`,
		HTTPStatusCodes: []int{http.StatusNotFound},
	},
	{
		Code:    ErrorCodeManifestInvalid,
		Value:   "MANIFEST_INVALID",
		Message: "manifest invalid",
		Description: `During upload, manifests undergo several checks ensuring
		validity. If those checks fail, this error may be returned, unless a
		more specific error is included. The detail will contain information
		the failed validation.`,
		HTTPStatusCodes: []int{http.StatusBadRequest},
	},
	{
		Code:    ErrorCodeManifestUnverified,
		Value:   "MANIFEST_UNVERIFIED",
		Message: "manifest failed signature verification",
		Description: `During manifest upload, if the manifest fails signature
		verification, this error will be returned.`,
		HTTPStatusCodes: []int{http.StatusBadRequest},
	},
	{
		Code:    ErrorCodeBlobUnknown,
		Value:   "BLOB_UNKNOWN",
		Message: "blob unknown to registry",
		Description: `This error may be returned when a blob is unknown to the
		registry in a specified repository. This can be returned with a
		standard get or if a manifest references an unknown layer during
		upload.`,
		HTTPStatusCodes: []int{http.StatusBadRequest, http.StatusNotFound},
	},

	{
		Code:    ErrorCodeBlobUploadUnknown,
		Value:   "BLOB_UPLOAD_UNKNOWN",
		Message: "blob upload unknown to registry",
		Description: `If a blob upload has been cancelled or was never
		started, this error code may be returned.`,
		HTTPStatusCodes: []int{http.StatusNotFound},
	},
	{
		Code:    ErrorCodeBlobUploadInvalid,
		Value:   "BLOB_UPLOAD_INVALID",
		Message: "blob upload invalid",
		Description: `The blob upload encountered an error and can no
		longer proceed.`,
		HTTPStatusCodes: []int{http.StatusNotFound},
	},
}

var errorCodeToDescriptors map[ErrorCode]ErrorDescriptor
var idToDescriptors map[string]ErrorDescriptor
var routeDescriptorsMap map[string]RouteDescriptor

func init() {
	errorCodeToDescriptors = make(map[ErrorCode]ErrorDescriptor, len(errorDescriptors))
	idToDescriptors = make(map[string]ErrorDescriptor, len(errorDescriptors))
	routeDescriptorsMap = make(map[string]RouteDescriptor, len(routeDescriptors))

	for _, descriptor := range errorDescriptors {
		errorCodeToDescriptors[descriptor.Code] = descriptor
		idToDescriptors[descriptor.Value] = descriptor
	}
	for _, descriptor := range routeDescriptors {
		routeDescriptorsMap[descriptor.Name] = descriptor
	}
}
