#' Perform a GET request with retries
#'
#' This function attempts to perform a GET request to the specified URL with the provided headers 
#' and checks for a specific HTTP status code. It retries the request if the desired status code is not received, 
#' or if the request results in an error.
#'
#' @param url_with_params The full URL to which the GET request is made, including any necessary query parameters.
#' @param headers A list of headers to include in the GET request.
#' @param code The desired HTTP status code for a successful request.
#'
#' @return NULL if the request does not succeed within the retry limit or if the desired status code is not achieved. 
#' Otherwise, returns the response from the successful GET request.
#' @examples
#' \dontrun{
#'   url <- "http://example.com/api"
#'   headers <- list(Authorization = "Bearer TOKEN", Accept = "application/json")
#'   code <- 200  # Looking for a '200 OK' response
#'   response <- requests(url, headers, code)
#'   if (is.null(response)) {
#'     print("Request failed or did not return the expected status code.")
#'   } else {
#'     print("Request succeeded.")
#'   }
#' }
#' @export
#' @import httr
request_api <- function(url_with_params,headers,code,retry_limit=5,timesleep=20){
    retry_count <- 0
    success <- FALSE

    while(retry_count < retry_limit && !success) {
        response <- tryCatch(httr::GET(url_with_params, headers),error=function(e){print(e);NULL})
        print(response)
        if(!is.null(response) && (response$status_code %in% code)) {
            success <- TRUE
        } else {
            print(url_with_params)
            print(paste0("retry #",retry_count,"/",retry_limit))
            retry_count <- retry_count + 1
            Sys.sleep(timesleep*(1+retry_count/retry_limit))
        }
    }
    if(!success) return(NULL)
    else return(response)

}