import {z} from 'zod'

export type GetApiV2FrequencyArgs = {region?: string | undefined, start?: string | undefined, end?: string | undefined};

export type GetApiV2FrequencyOptions = {baseUrl: string, fetch?: typeof fetch | undefined};

export const seriesDescriptorV2 = z.object({id: z.string(), name: z.string(), unit: z.string().nullable().optional(), description: z.string().nullable().optional()});

export const dataPointV2 = z.object({timestamp: z.string(), values: z.record(z.string(), z.union([z.number(), z.number().int()]).nullable())});

export const timeSeriesResponseV2 = z.object({schema_version: z.string(), endpoint: z.string(), country: z.string().nullable().optional(), bidding_zone: z.string().nullable().optional(), timezone: z.string(), resolution: z.string().nullable().optional(), interval_minutes: z.number().int().nullable().optional(), unit: z.string().nullable().optional(), generated_at: z.string(), available_from: z.string().nullable().optional(), available_until: z.string().nullable().optional(), series: z.array(seriesDescriptorV2), data: z.array(dataPointV2), attributes: z.record(z.string(), z.string()).optional(), license: z.string().nullable().optional(), deprecated: z.boolean()});

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
};

/**
 * Grid frequency (RG Continental Europe), 1 second resolution
 * 
 * GET /v2/frequency
 */
export const getApiV2Frequency = async (args: GetApiV2FrequencyArgs, options: GetApiV2FrequencyOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

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

const url = `${baseUrl.replace(/\/+$/, '')}/v2/frequency${query.size > 0 ? `?${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(timeSeriesResponseV2, await res.json())
};