import {z} from 'zod'

export type V3Signals = 'co2_moer' | 'health_damage';

export type V3HistoricalSignals = 'co2_aoer';

export type GetApiV3MapsArgs = {signal_type: V3Signals | V3HistoricalSignals | unknown};

export type GetApiV3MapsOptions = {baseUrl?: string | undefined, BearerAuth?: string | undefined, fetch?: typeof fetch | undefined};

export const properties = z.object({region: z.string(), region_full_name: z.string()});

export const geometry = z.object({type: z.literal("MultiPolygon"), coordinates: z.array(z.array(z.array(z.array(z.number()))))});

export const feature = z.object({type: z.literal("Feature"), properties: properties, geometry: geometry});

export const v3Signals = z.enum(["co2_moer", "health_damage"]);

export const v3HistoricalSignals = z.literal("co2_aoer");

export const meta = z.object({last_updated: z.string(), signal_type: z.union([v3Signals, v3HistoricalSignals, z.unknown()])});

export const map = z.object({type: z.literal("FeatureCollection"), features: z.array(feature), meta: meta});

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 Region Map Geometry
 * 
 * GET /v3/maps
 */
export const getApiV3Maps = async (args: GetApiV3MapsArgs, options?: GetApiV3MapsOptions) => {
const {baseUrl = "https://api.watttime.org", fetch: fetchFn = fetch, BearerAuth} = options ?? {}

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

if (args.signal_type != null) query.append("signal_type", String(args.signal_type))
if (BearerAuth !== undefined) headers.set('authorization', `Bearer ${BearerAuth}`)

const url = `${baseUrl.replace(/\/+$/, '')}/v3/maps${query.size > 0 ? `?${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(map, await res.json())
};