import {z} from 'zod'

export type AuthorizationCodeTokenRequest = {grant_type: 'authorization_code', code: string, client_id: string, redirect_uri: string, code_verifier: string};

export type DeviceCodeTokenRequest = {grant_type: 'urn:ietf:params:oauth:grant-type:device_code', device_code: string, client_id: string};

export type RefreshTokenRequest = {grant_type: 'refresh_token', refresh_token: string, client_id: string};

export type OAuthTokenRequest = AuthorizationCodeTokenRequest | DeviceCodeTokenRequest | RefreshTokenRequest;

export type CreateApiV1OauthTokenArgs = {body: OAuthTokenRequest};

export type CreateApiV1OauthTokenOptions = {baseUrl?: string | undefined, fetch?: typeof fetch | undefined};

export const oAuthScopeList = z.array(z.string().min(1));

export const oAuthTokenResponse = z.object({access_token: z.string().min(1), refresh_token: z.string().min(1), token_type: z.literal("Bearer"), expires_in: z.number().int().gte(1), scope: oAuthScopeList});

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
};

/**
 * Exchange or refresh an isolated Desktop, CLI, or MCP credential
 * 
 * POST /v1/oauth/token
 */
export const createApiV1OauthToken = async (args: CreateApiV1OauthTokenArgs, options?: CreateApiV1OauthTokenOptions) => {
const {baseUrl = "https://api.cerul.ai", fetch: fetchFn = fetch} = options ?? {}

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

const url = `${baseUrl.replace(/\/+$/, '')}/v1/oauth/token${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "POST", headers, body: JSON.stringify(args.body)})

if (!res.ok) throw new Error(`Request failed with status ${res.status}`, {cause: {status: res.status, body: await res.text()}})

return validateResponse(oAuthTokenResponse, await res.json())
};