import {z} from 'zod'

export type GetApiV1FeatureFlagsSnapshotArgs = {Account: unknown, platform: string, app_version?: string | undefined};

export type GetApiV1FeatureFlagsSnapshotOptions = {baseUrl: string, OAuth2?: string | undefined, fetch?: typeof fetch | undefined};

export const featureFlagSnapshotResponse = z.object({flags: z.record(z.string(), z.boolean()).nullable().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
};

/**
 * Every flag that resolves to a decision for this caller, as a flat map of key to value.
 * 
 * GET /v1/FeatureFlags/snapshot
 */
export const getApiV1FeatureFlagsSnapshot = async (args: GetApiV1FeatureFlagsSnapshotArgs, options: GetApiV1FeatureFlagsSnapshotOptions) => {
const {baseUrl, fetch: fetchFn = fetch, OAuth2} = options ?? {}

const query = new URLSearchParams()
const headers = new Headers()
headers.set('accept', "application/json; x-api-version=1.0")

if (args.Account != null) query.append("Account", String(args.Account))
if (args.platform != null) query.append("platform", String(args.platform))
if (args.app_version != null) query.append("app_version", String(args.app_version))
if (OAuth2 !== undefined) headers.set('authorization', `Bearer ${OAuth2}`)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/FeatureFlags/snapshot${query.size > 0 ? `?${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(featureFlagSnapshotResponse, await res.json())
};