import {z} from 'zod'

export type GetApiPublicV1VariantsReferenceArgs = {chrom: string, start: number, end: number};

export type GetApiPublicV1VariantsReferenceOptions = {baseUrl: string, fetch?: typeof fetch | undefined};

export const publicReferenceCodon = z.object({bases: z.string(), aminoAcid: z.string(), proteinPosition: z.number().int().gte(1), genomicPositions: z.array(z.number().int())});

export const publicReferenceTranscript = z.object({geneSymbol: z.string(), transcriptId: z.string(), proteinId: z.string().nullable(), strand: z.enum(["+", "-"]), exons: z.array(z.array(z.unknown())), cds: z.array(z.array(z.unknown())), codons: z.array(publicReferenceCodon)});

export const publicReferenceResponse = z.object({chrom: z.string(), start: z.number().int().gte(1), end: z.number().int().gte(1), sequence: z.string(), transcript: publicReferenceTranscript.nullable()});

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
};

/**
 * Read a bounded public GRCh38 and MANE reference window
 * 
 * GET /public/v1/variants/reference
 */
export const getApiPublicV1VariantsReference = async (args: GetApiPublicV1VariantsReferenceArgs, options: GetApiPublicV1VariantsReferenceOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

if (args.chrom != null) query.append("chrom", String(args.chrom))
if (args.start != null) query.append("start", String(args.start))
if (args.end != null) query.append("end", String(args.end))

const url = `${baseUrl.replace(/\/+$/, '')}/public/v1/variants/reference${query.size > 0 ? `?${query}` : ''}`

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

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

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