##' geom_text2 support aes(subset) via setup_data
 ##'

 ##'

 ##' @title geom_text2

 ##' @param mapping the aesthetic mapping
 ##' @param data A layer specific dataset -
 ##'             only needed if you want to override he plot defaults.
 ##' @param position The position adjustment to use for overlapping points on this layer

 ##' @param family sans by default, can be any supported font

 ##' @param parse if TRUE, the labels will be passd into expressions

 ##' @param na.rm logical
 ##' @param show.legend logical
 ##' @param inherit.aes logical

 ##' @param ... other arguments passed on to 'layer'

 ##' @param nudge_x horizontal adjustment
 ##' @param nudge_y vertical adjustment
 ##' @param check_overlap if TRUE, text that overlaps previous text in the same layer will not be plotted

 ##' @return text layer
 ##' @importFrom ggplot2 layer
 ##' @importFrom ggplot2 position_nudge

 ##' @importFrom ggplot2 aes_string

 ##' @export

 ##' @seealso
 ##' \link[ggplot2]{geom_text}

 ##' @author Guangchuang Yu

 geom_text2 <- function(mapping = NULL, data = NULL,

                        position = "identity", family="sans", parse = FALSE,
                        na.rm=TRUE, show.legend = NA, inherit.aes = TRUE,

                        ..., nudge_x = 0, nudge_y = 0, check_overlap = FALSE) {
 
     if (!missing(nudge_x) || !missing(nudge_y)) {
         if (!missing(position)) {
             stop("Specify either `position` or `nudge_x`/`nudge_y`", call. = FALSE)
         }

         position <- position_nudge(nudge_x, nudge_y)
     }

     default_aes <- aes_(node=~node)
     if (is.null(mapping)) {
         mapping <- default_aes
     } else {
         mapping <- modifyList(mapping, default_aes)
     }

     if (parse == "emoji") {
         label_aes <- aes_string(label=paste0("suppressMessages(emoji(", as.list(mapping)$label,"))"))
         mapping <- modifyList(mapping, label_aes)
         emoji <- get_fun_from_pkg("emojifont", "emoji")
         parse <- FALSE
         family <- "OpenSansEmoji"
     }
 

     layer(
         data = data,
         mapping = mapping,

         stat = StatTreeData,

         geom = GeomTextGGtree,
         position = position,
         show.legend = show.legend,
         inherit.aes = inherit.aes,
         params = list(

             parse = parse,
             family = family,
             check_overlap = check_overlap,
             na.rm = na.rm,
             ...

         ),

         check.aes = FALSE

     )
 }

 
 ##' @importFrom ggplot2 GeomText
 ##' @importFrom ggplot2 draw_key_text
 GeomTextGGtree <- ggproto("GeomTextGGtree", GeomText,
                           setup_data = function(data, params) {

                               if (is.null(data$subset))
                                   return(data)

                               data[which(data$subset),] ## use `which` makes it compatible with NA

                           },

                           ## compute_group = function(data, params) {
                           ##     data
                           ## },

                           draw_panel = function(data, panel_scales, coord, parse = FALSE,

                               na.rm = TRUE, check_overlap = FALSE) {

                               GeomText$draw_panel(data, panel_scales, coord, parse,
                                                   na.rm, check_overlap)
                           },

                           required_aes = c("node", "x", "y", "label"),

                           default_aes = aes(colour = "black", size = 3.88, angle = 0, hjust = 0.5,
                               vjust = 0.5, alpha = NA, family = "", fontface = 1, lineheight = 1.2),

                           draw_key = draw_key_text
                           )

 StatTreeData <-  ggproto("StatTreeLabel", Stat,
                          required_aes = "node",
                          compute_group = function(data, scales) {
                              setup_tree_data(data)
                          }
                          )