import {z} from 'zod'

export type GetApiDeparturesArgs = {lat: number, lon: number, radius?: number | undefined, limit?: number | undefined, mode?: string | undefined, from?: number | undefined, to?: number | undefined, dedup?: ('nearest' | 'off') | undefined, stops?: string | undefined, alerts?: 1 | undefined};

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

export const departure = z.object({line: z.string().min(1), direction: z.string().min(1), time: z.string().min(1), timestamp: z.number().int(), stop: z.string().min(1), platform: z.string().optional(), delay: z.number().int(), cancelled: z.boolean(), occupancy: z.string().optional(), mode: z.enum(["subway", "suburban", "tram", "bus", "ferry", "regional", "express"]).optional(), color: z.string().optional(), alerts: z.array(z.string()).optional()});

export const station = z.object({id: z.string().min(1), name: z.string().min(1), distance: z.number().int(), walkSeconds: z.number().int(), lat: z.number().optional(), lon: z.number().optional()});

export const bounds = z.object({north: z.number(), south: z.number(), east: z.number(), west: z.number()});

export const disruption = z.object({id: z.string(), severity: z.enum(["info", "warning", "severe"]), effect: z.enum(["cancellation", "delay", "detour", "stop_moved", "replacement_service", "accessibility", "other"]).optional(), title: z.string(), description: z.string().optional(), lines: z.array(z.string()).optional(), stopNames: z.array(z.string()).optional(), mode: z.enum(["subway", "suburban", "tram", "bus", "ferry", "regional", "express"]).optional(), validFrom: z.number().int().optional(), validTo: z.number().int().optional(), url: z.string().optional(), source: z.string(), attribution: z.string().optional()});

export const departureResponse = z.object({region: z.string(), city: z.string().optional(), realtime: z.boolean(), routing: z.boolean(), departures: z.array(departure), stations: z.array(station).optional(), regionBounds: bounds.optional(), routingBounds: z.array(bounds).optional(), attribution: z.string().optional(), timeTravelSupported: z.boolean().optional(), timeTravelHorizonMinutes: z.number().int().optional(), radiusUsed: z.number().int().optional(), forTime: z.string().optional(), disruptions: z.array(disruption).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
};

/**
 * Get nearby departures
 * 
 * GET /departures
 * 
 * Also accepts auth: ApiKeyQuery
 */
export const getApiDepartures = async (args: GetApiDeparturesArgs, options?: GetApiDeparturesOptions) => {
const {baseUrl = "https://api.abfahrt.now", fetch: fetchFn = fetch, ApiKeyHeader} = options ?? {}

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

if (args.lat != null) query.append("lat", String(args.lat))
if (args.lon != null) query.append("lon", String(args.lon))
if (args.radius != null) query.append("radius", String(args.radius))
if (args.limit != null) query.append("limit", String(args.limit))
if (args.mode != null) query.append("mode", String(args.mode))
if (args.from != null) query.append("from", String(args.from))
if (args.to != null) query.append("to", String(args.to))
if (args.dedup != null) query.append("dedup", String(args.dedup))
if (args.stops != null) query.append("stops", String(args.stops))
if (args.alerts != null) query.append("alerts", String(args.alerts))
if (ApiKeyHeader !== undefined) headers.set("x-api-key", ApiKeyHeader)

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