#' Bulma Document Renderer
#'
#' @section YAML options:
#' You can pass additional options to the underlying template via the `bulma`
#' YAML item. The following options can be specified there.
#' \itemize{
#'   \item{`hero`: Classes applied to the hero containing the title.}
#'   \item{`hero_body`: Classes applied to the hero body container.}
#'   \item{`hero_button`: Classes applied to the `header_links` buttons}
#'   \item{`hero_links`: Links that will be displayed under title as buttons.
#'         Formatted as a list, each element having entries for `name`, `url`,
#'         and `icon`. Icons use [Font Awesome](https://fontawesome.com/icons);
#'         see [fa_icon()] for help constructing the Font Awesome class. The
#'         full Font Awesome class name is required.}
#' }
#'
#' ```
#' ---
#' bulma:
#'   hero: ["info"]
#'   hero_button: ["is-secondary", "is-outlined"]
#'   hero_links:
#'     - name: Github
#'       url: https://github.com/
#'       icon: '`r bulma::fa_icon("github")`'
#'     - name: Twitter
#'       url: https://twitter.com
#'       icon: "fab fa-twitter"
#' ---
#' ```
#'
#' @inheritDotParams rmarkdown::html_document_base
#' @export
bulma_document <- function(
  ...,
  css = NULL,
  fig_width = 10,
  fig_height = 7,
  fig_retina = 2,
  keep_md = FALSE,
  dev = "png",
  pandoc_args = NULL,
  extra_dependencies = NULL
) {
  css_files <- c(
    "--css", bulma_file("bulma", "bulma.0.7.2.min.css"))

  if (!is.null(css)) {
    for (css_file in css) {
      css_files <- c(css_files, "--css", css_file)
    }
  }
  # rmarkdown::html_document_base(
    # pandoc_args = c(
    #   css_files,
    #   pandoc_args,
    #   "--template",
    #   system.file("bulma", "bulma.html", package="bulma")
    # ),
  #   ...
  # )
  deps <- htmltools::htmlDependency(
      name = "bulma",
      version = "0.7.2",
      src = bulma_file("bulma"),
      stylesheet = "bulma.0.7.2.min.css"
    )
  extra_dependencies <- append(extra_dependencies, list(deps, rmarkdown::html_dependency_font_awesome()))

  # preprocessor ----
  pre_processor <- function(metadata, input_file, runtime, knit_meta, files_dir, output_dir) {
    # browser()
  }

  rmarkdown::output_format(
    knitr = rmarkdown::knitr_options_html(
      fig_width, fig_height, fig_retina, keep_md, dev
    ),
    pandoc = rmarkdown::pandoc_options(
      to = "html",
      from = "markdown+ascii_identifiers+tex_math_single_backslash",
      args = c(
        css_files,
        pandoc_args,
        "--template",
        bulma_file("bulma", "bulma.html")
      ),
    ),
    pre_processor = pre_processor,
    clean_supporting = TRUE,
    base_format = rmarkdown::html_document_base(
      self_contained = TRUE, template = NULL,
      pandoc_args = pandoc_args,
      extra_dependencies = extra_dependencies
    )
  )
}


bulma_file <- function(...) {
  system.file(..., package = "bulma")
}