#' Create an apexcharts.js widget
#'
#' @param ax_opts A \code{list} in JSON format with chart parameters.
#' @param auto_update In Shiny application, update existing chart
#'  rather than generating new one. Can be \code{TRUE}/\code{FALSE} or
#'  use \code{\link{config_update}} for more control.
#' @param width A numeric input in pixels.
#' @param height A numeric input in pixels.
#' @param elementId Use an explicit element ID for the widget.
#'
#' @return A \code{apexcharts} \code{htmlwidget} object.
#' @export
#'
#' @importFrom htmlwidgets createWidget sizingPolicy
#'
#' @example examples/apexchart.R
apexchart <- function(ax_opts = list(), auto_update = TRUE, width = NULL, height = NULL, elementId = NULL) {
  
  if (isTRUE(auto_update)) {
    auto_update <- config_update()
  }

  x <- list(
    ax_opts = ax_opts,
    auto_update = auto_update
  )

  # create widget
  htmlwidgets::createWidget(
    name = "apexcharter",
    x = x,
    width = width,
    height = height,
    package = "apexcharter",
    elementId = elementId,
    preRenderHook = add_locale_apex,
    sizingPolicy = htmlwidgets::sizingPolicy(
      defaultWidth = "100%",
      defaultHeight = "100%",
      viewer.defaultHeight = "100%",
      viewer.defaultWidth = "100%",
      knitr.figure = FALSE,
      knitr.defaultWidth = "100%",
      knitr.defaultHeight = "350px",
      browser.fill = TRUE,
      viewer.suppress = FALSE,
      browser.external = TRUE,
      padding = 0
    )
  )
}

#' @importFrom jsonlite fromJSON
add_locale_apex <- function(widget) {
  if (!is.null(widget$x$ax_opts$chart$defaultLocale)) {
    defaultLocale <- widget$x$ax_opts$chart$defaultLocale
    defaultLocale <- match.arg(
      arg = defaultLocale,
      choices = c("ca", "de", "el", "en", "es", "fi", "fr", "hi", "hr", "hy",
                  "id", "it", "ko", "nl", "pt-br", "ru", "se", "tr", "ua")
    )
    if (!is.null(widget$x$ax_opts$chart$locales)) {
      warning(
        "defaultLocale is used but will be ignored since",
        " a custom array for locales is provided."
      )
    } else {
      path <- system.file(
        file.path("htmlwidgets/lib/apexcharts-locales", paste0(defaultLocale, ".json")),
        package = "apexcharter"
      )
      locale <- jsonlite::fromJSON(txt = path)
      widget$x$ax_opts$chart$locales <- list(locale)
    }
  }
  widget
}



#' Configuration for auto update
#'
#' @param series_animate Should the chart animate on re-rendering.
#' @param update_options Update or not global options for chart.
#' @param options_animate Should the chart animate on re-rendering.
#' @param options_redrawPaths When the chart is re-rendered,
#'  should it draw from the existing paths or completely redraw 
#'  the chart paths from the beginning. By default, the chart 
#'  is re-rendered from the existing paths.
#' @param update_synced_charts All the charts in a group should
#'  also update when one chart in a group is updated.
#' 
#' @export
config_update <- function(series_animate = TRUE, 
                          update_options = FALSE, 
                          options_animate = TRUE, 
                          options_redrawPaths = TRUE,
                          update_synced_charts = FALSE) {
  list(
    series_animate = series_animate, 
    update_options = update_options, 
    options_animate = options_animate, 
    options_redrawPaths = options_redrawPaths,
    update_synced_charts = update_synced_charts
  )
}


#' @title Shiny bindings for apexcharter
#'
#' @description Output and render functions for using apexcharter within Shiny
#' applications and interactive Rmd documents.
#'
#' @param outputId output variable to read from
#' @param width,height Must be a valid CSS unit (like \code{'100\%'},
#'   \code{'400px'}, \code{'auto'}) or a number, which will be coerced to a
#'   string and have \code{'px'} appended.
#' @param expr An expression that generates a apexcharter
#' @param env The environment in which to evaluate \code{expr}.
#' @param quoted Is \code{expr} a quoted expression (with \code{quote()})? This
#'   is useful if you want to save an expression in a variable.
#'   
#' @return An Apexchart output that can be included in the application UI.
#'
#' @name apexcharter-shiny
#'
#' @export
#'
#' @importFrom htmlwidgets shinyWidgetOutput shinyRenderWidget
#' 
#' @example examples/apexcharter-shiny.R
apexchartOutput <- function(outputId, width = "100%", height = "400px"){
  htmlwidgets::shinyWidgetOutput(outputId, "apexcharter", width, height, package = "apexcharter")
}

#' @rdname apexcharter-shiny
#' @export
renderApexchart <- function(expr, env = parent.frame(), quoted = FALSE) {
  if (!quoted) { expr <- substitute(expr) } # force quoted
  htmlwidgets::shinyRenderWidget(expr, apexchartOutput, env, quoted = TRUE)
}