#' Get user country report from matomo API server
#'
#' See matomo Reporting API Reference (\url{https://developer.matomo.org/api-reference/reporting-api}) for details.
#'
#' @references \url{https://developer.matomo.org/api-reference/reporting-api}
#'
#' @inheritParams matomoQuery
#'
#' @importFrom stringr str_replace str_replace_all str_split
#'
#' @examples
#' \dontrun{
#' df <- getUserCountry("https://demo.matomo.org/", siteId=3, period="day", date="last60")
#' }
#'
#' @export
getUserCountry <- function(matomoUrl,
                             siteId,
                             period = "month",
                             date = "last36",
                             filter_limit = 100,
                             accessToken = getAccessToken(matomoUrl)
) {
  result <- list()
  MAX_RETRIES <- 5
  retry_count <- 0

  while (length(result) == 0 && retry_count < MAX_RETRIES) {
    result <- matomoQuery(matomoUrl = matomoUrl,
                siteId = siteId,
                period = period,
                date = str_replace_all(str_replace_all(date, " *UTC", ""), "-00", "-01"),
                removeFirst = FALSE,
                removeLast = FALSE,
                accessToken = accessToken,
                getMethod = "UserCountry.getCountry",
                ignoreEmptyResult = retry_count < MAX_RETRIES)

    if (length(result) == 0 && retry_count < MAX_RETRIES) {
      msg <- paste0("UserCountry.getCountry returned an empty list (known MATOMO bug). Changing date range from ", date, " to ")
      retry_count <- retry_count + 1
      startend <- str_split(date, ",", simplify = T)
      l <- str_split(startend[1], "-", simplify = T)
      l[3] <- sprintf("%02d", as.numeric(l[3]) + 1)
      date <- paste0(paste0(l, collapse = "-"), ",", startend[2])
      msg <- paste0(msg, date, "\n")
      warning(msg)
    }
  }
  return(result)
}