R/fnc_show_help.R

In eCerto: Statistical Tests for the Production of Reference Materials

#' @title show_help.
#' @description Help Window: opens a modal with in memory rendering of simple Rmd files.
#' @param filename name of the file as string (if necessary, containing also path)
#' @param show_modal Will show the returned help_text in a modal. Can be suppressed by setting to FALSE for testing purposes.
#' @return Returns the help text as HTML (currently produces errors when used)
#' @examples
#' eCerto:::show_help(
#'   filename = system.file("app/www/rmd/start_gethelp.Rmd", package = "eCerto"),
#'   show_modal = FALSE
#' )
#' @noRd
#' @keywords internal
#' @importFrom markdown mark_html
show_help <- function(filename, show_modal = TRUE) {
  # check if valid path was provided and look up file in 'www' otherwise
  if (!file.exists(filename)) {
    srp <- shiny::resourcePaths()["www"]
    if (is.na(srp)) stop("No 'shiny::resourcePaths()['www']' defined")
    file_in <- list.files(path = srp, pattern = paste0(filename, ".[Rr][Mm][Dd]$"), recursive = TRUE, full.names = TRUE)
  } else {
    file_in <- filename
  }
  help_text <- NULL
  if (length(file_in) == 1 && file.exists(file_in)) {
    e_msg(paste("Rendering Rmd file:", file_in))
    help_text <- shiny::withMathJax(
      shiny::HTML(
        # markdown::mark_html(file = file_in, options = "+tables+autolink+latex_math-standalone")
        markdown::markdownToHTML(file = file_in, fragment.only = TRUE)
      )
    )
    if (show_modal) {
      shiny::showModal(
        shiny::modalDialog(
          help_text,
          footer = NULL,
          size = "l",
          easyClose = TRUE,
          title = NULL
        )
      )
    }
  } else {
    e_msg(paste("cant find help file:", filename))
  }
  return(help_text)
}