import { parseCookies, type PayloadRequest } from "payload"
import * as oauth from "oauth4webapi"
import type { OAuth2ProviderConfig, AccountInfo } from "../../../types.js"
import { getCallbackURL } from "../../utils/cb.js"
import { MissingOrInvalidSession } from "../../errors/consoleErrors.js"

export async function OAuth2Callback(
  pluginType: string,
  request: PayloadRequest,
  providerConfig: OAuth2ProviderConfig,
  session_callback: (
    oauthAccountInfo: AccountInfo,
    clientOrigin: string,
  ) => Promise<Response>,
): Promise<Response> {
  const parsedCookies = parseCookies(request.headers)

  const code_verifier = parsedCookies.get("__session-code-verifier")
  const state = parsedCookies.get("__session-oauth-state")
  const clientOrigin = parsedCookies.get("__client-origin")

  if (!code_verifier || !clientOrigin) {
    throw new MissingOrInvalidSession()
  }

  const {
    client_id,
    client_secret,
    authorization_server,
    profile,
    client_auth_type,
  } = providerConfig

  const client: oauth.Client = {
    client_id,
  }

  const clientAuth =
    client_auth_type === "client_secret_basic"
      ? oauth.ClientSecretBasic(client_secret ?? "")
      : oauth.ClientSecretPost(client_secret ?? "")

  const current_url = new URL(request.url as string) as URL
  const callback_url = getCallbackURL(
    request.payload.config.serverURL,
    pluginType,
    providerConfig.id,
  )
  const as = authorization_server

  const params = oauth.validateAuthResponse(as, client, current_url, state!)

  const grantResponse = await oauth.authorizationCodeGrantRequest(
    as,
    client,
    clientAuth,
    params,
    callback_url.toString(),
    code_verifier,
  )
  let body = (await grantResponse.json()) as { scope: string | string[] }
  let response = new Response(JSON.stringify(body), grantResponse)
  if (Array.isArray(body.scope)) {
    body.scope = body.scope.join(" ")
    response = new Response(JSON.stringify(body), grantResponse)
  }

  const token_result = await oauth.processAuthorizationCodeResponse(
    as,
    client,
    response,
  )

  const userInfoResponse = await oauth.userInfoRequest(
    as,
    client,
    token_result.access_token,
  )
  const userInfo = (await userInfoResponse.json()) as Record<string, string>
  return session_callback(profile(userInfo), clientOrigin)
}