import {z} from 'zod'

export type Limit = number;

export type GetApiCollectionsArgs = {limit?: Limit | undefined, provider?: string | undefined};

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

export const extent = z.object({spatial: z.object({bbox: z.array(z.array(z.number()))}), temporal: z.object({interval: z.array(z.array(z.string()))})});

export const license = z.string();

export const providers = z.array(z.object({description: z.string().optional(), name: z.string(), roles: z.array(z.enum(["producer", "licensor", "processor", "host"])).optional(), url: z.string().optional()}));

export const stacVersion = z.string();

export const created = z.string();

export const updated = z.string();

export const assetType = z.string();

export const title = z.string().min(1).max(255);

export const description = z.string();

export const href = z.string();

export const checksumMultihashReadOnly = z.string();

export const roles = z.array(z.enum(["data", "overview", "thumbnail", "metadata"]));

export const geoadminVariant = z.string();

export const geoadminLang = z.enum(["de", "it", "fr", "rm", "en"]);

export const projEpsg = z.number().int();

export const eoGsd = z.number();

export const itemAssets = z.record(z.string(), z.object({type: assetType, title: title.optional(), description: description.optional(), href: href.optional(), "file:checksum": checksumMultihashReadOnly.optional(), roles: roles.optional(), "geoadmin:variant": geoadminVariant.optional(), "geoadmin:lang": geoadminLang.optional(), "proj:epsg": projEpsg.optional(), gsd: eoGsd.optional(), created: created, updated: updated}));

export const link = z.object({href: z.string(), rel: z.string(), title: z.string().optional(), type: z.string().optional(), method: z.enum(["GET", "POST"]).optional(), hreflang: z.string().optional()});

export const collection = z.object({crs: z.array(z.string()).optional(), description: z.string(), extent: extent, id: z.string(), itemType: z.string().optional(), type: z.string(), license: license, providers: providers.optional(), stac_version: stacVersion, summaries: z.record(z.string(), z.union([z.array(z.unknown()), z.object({max: z.union([z.string(), z.number()]), min: z.union([z.string(), z.number()])})])).optional(), title: z.string().optional(), created: created, updated: updated, assets: itemAssets.optional(), links: z.array(link)});

export const collections = z.object({collections: z.array(collection), links: z.array(link)});

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
};

/**
 * Fetch collections
 * 
 * GET /collections
 */
export const getApiCollections = async (args: GetApiCollectionsArgs, options?: GetApiCollectionsOptions) => {
const {baseUrl = "https://data.geo.admin.ch/api/stac/v1", fetch: fetchFn = fetch} = options ?? {}

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

if (args.limit != null) query.append("limit", String(args.limit))
if (args.provider != null) query.append("provider", String(args.provider))

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