import {z} from 'zod'

export type HeadApiV2NameBlobsDigestArgs = {name: string, digest: string};

export type HeadApiV2NameBlobsDigestOptions = {baseUrl: string, fetch?: typeof fetch | undefined};

export const v1Platform = z.object({architecture: z.string().optional(), os: z.string().optional(), "os.features": z.array(z.string()).optional(), "os.version": z.string().optional(), variant: z.string().optional()});

export const v1Descriptor = z.object({annotations: z.record(z.string(), z.string()).optional(), artifactType: z.string().optional(), data: z.array(z.number().int()).optional(), digest: z.string().optional(), mediaType: z.string().optional(), platform: v1Platform.optional(), size: z.number().int().optional(), urls: z.array(z.string()).optional()});

export const apiImageManifest = z.object({annotations: z.record(z.string(), z.string()).optional(), artifactType: z.string().optional(), config: v1Descriptor.optional(), layers: z.array(v1Descriptor).optional(), mediaType: z.string().optional(), schemaVersion: z.number().int().optional(), subject: v1Descriptor.optional()});

export const validateResponse = async <Output>(
  schema: {
    readonly '~standard': {
      readonly validate: (value: unknown) => ({ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }) | Promise<{ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }>
    }
  },
  value: unknown
): Promise<Output> => {
  const result = await schema['~standard'].validate(value)

  if (result.issues !== undefined) {
    const detail = result.issues
      .map(({ message, path }) =>
        path?.length
          ? `${path.map((segment) => String(typeof segment === 'object' ? segment.key : segment)).join('.')}: ${message}`
          : message
      )
      .join('; ')

    throw new Error(`Response does not match the schema: ${detail}`, { cause: { issues: result.issues } })
  }

  return result.value
};

/**
 * Check image blob/layer
 * 
 * HEAD /v2/{name}/blobs/{digest}
 */
export const headApiV2NameBlobsDigest = async (args: HeadApiV2NameBlobsDigestArgs, options: HeadApiV2NameBlobsDigestOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

const query = new URLSearchParams()
const headers = new Headers()
headers.set('accept', "application/json")

const url = `${baseUrl.replace(/\/+$/, '')}/v2/${encodeURIComponent(String(args.name))}/blobs/${encodeURIComponent(String(args.digest))}${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "HEAD", headers})

if (!res.ok) throw new Error(`Request failed with status ${res.status}`, {cause: {status: res.status, body: await res.text()}})

return validateResponse(apiImageManifest, await res.json())
};