#' @include utilities.R
NULL
#' Arrange Multiple ggplots
#'
#' @description Arrange multiple ggplots on the same page. Wrapper around
#'   \code{\link[cowplot]{plot_grid}()}. Can arrange multiple ggplots over
#'   multiple pages, compared to the standard
#'   \code{\link[cowplot]{plot_grid}()}. Can also create a common unique legend
#'   for multiple plots.
#' @inheritParams cowplot::plot_grid
#' @param ... list of plots to be arranged into the grid. The plots can be
#'   either ggplot2 plot objects or arbitrary gtables.
#' @param plotlist (optional) list of plots to display.
#' @param ncol (optional) number of columns in the plot grid.
#' @param nrow (optional) number of rows in the plot grid.
#' @param labels (optional) list of labels to be added to the plots. You can
#'   also set labels="AUTO" to auto-generate upper-case labels or labels="auto"
#'   to auto-generate lower-case labels.
#' @param font.label a list of arguments for customizing labels. Allowed values
#'   are the combination of the following elements: size (e.g.: 14), face (e.g.:
#'   "plain", "bold", "italic", "bold.italic"), color (e.g.: "red") and family.
#'   For example font.label = list(size = 14, face = "bold", color ="red").
#' @param label.x (optional) Single value or vector of x positions for plot
#'   labels, relative to each subplot. Defaults to 0 for all labels. (Each label
#'   is placed all the way to the left of each plot.)
#' @param label.y (optional) Single value or vector of y positions for plot
#'   labels, relative to each subplot. Defaults to 1 for all labels. (Each label
#'   is placed all the way to the top of each plot.)
#' @param widths (optional) numerical vector of relative columns widths. For
#'   example, in a two-column grid, widths = c(2, 1) would make the first column
#'   twice as wide as the second column.
#' @param heights same as \code{widths} but for column heights.
#' @param legend character specifying legend position. Allowed values are one of
#'   c("top", "bottom", "left", "right", "none"). To remove the legend use
#'   legend = "none".
#' @param common.legend logical value. Default is FALSE. If TRUE, a common
#'   unique legend will be created for arranged plots.
#' @param legend.grob a legend grob as returned by the function
#'   \code{\link{get_legend}()}. If provided, it will be used as the common
#'   legend.
#' @return return an object of class \code{ggarrange}, which is a ggplot or a
#'   list of ggplot.
#' @author Alboukadel Kassambara \email{alboukadel.kassambara@@gmail.com}
#' @seealso \code{\link{annotate_figure}()}
#' @examples
#' data("ToothGrowth")
#' df <- ToothGrowth
#' df$dose <- as.factor(df$dose)
#'
#' # Create some plots
#' # ::::::::::::::::::::::::::::::::::::::::::::::::::
#' # Box plot
#' bxp <- ggboxplot(df, x = "dose", y = "len",
#'     color = "dose", palette = "jco")
#' # Dot plot
#' dp <- ggdotplot(df, x = "dose", y = "len",
#'     color = "dose", palette = "jco")
#' # Density plot
#' dens <- ggdensity(df, x = "len", fill = "dose", palette = "jco")
#'
#' # Arrange
#' # ::::::::::::::::::::::::::::::::::::::::::::::::::
#' ggarrange(bxp, dp, dens, ncol = 2, nrow = 2)
#' # Use a common legend for multiple plots
#' ggarrange(bxp, dp,  common.legend = TRUE)
#'
#'
#' @export
ggarrange <- function(..., plotlist = NULL, ncol = NULL, nrow = NULL,
                      labels = NULL, label.x = 0, label.y = 1, hjust = -0.5, vjust = 1.5,
                      font.label = list(size = 14, color = "black", face = "bold", family = NULL),
                      align = c("none", "h", "v", "hv"),
                      widths = 1, heights = 1,
                      legend = NULL, common.legend = FALSE, legend.grob = NULL )
  {

  plots <- c(list(...), plotlist)
  align <- match.arg(align)
  nb.plots <- length(plots)
  page.layout <- .get_layout(ncol, nrow, nb.plots)
  ncol <- page.layout$ncol
  nrow <- page.layout$nrow
  nb.plots.per.page <- .nbplots_per_page(ncol, nrow)

  if(!is.null(legend.grob))
    common.legend <- TRUE
  if(is.null(legend) & common.legend)
    legend <- "top"
  legend <- .check_legend(legend)
  if(!is.null(legend))
    plots <- purrr::map(
      plots,
      function(x) {if(!is.null(x)) x + theme(legend.position = legend) else x}
      )

  if(common.legend){
    if(is.null(legend.grob))
      legend.grob <- get_legend(plots)
    plots <- purrr::map(
      plots,
      function(x) {if(!is.null(x)) x + theme(legend.position = "none") else x}
    )
  }

  # Split plots over multiple pages
  if(nb.plots > nb.plots.per.page){
    plots <- split(plots, ceiling(seq_along(plots)/nb.plots.per.page))
  }
  # One unique page
  else plots <- list(plots)

  # label arguments
  .lab <- .update_label_pms(font.label, label.x = label.x, label.y = label.y,
                            hjust = hjust, vjust = vjust)

  res <- purrr::map(plots, .plot_grid,
              ncol = ncol, nrow = nrow, labels = labels,
              label_size = .lab$size, label_fontfamily = .lab$family,
              label_fontface = .lab$face, label_colour = .lab$color,
              label_x = .lab$label.x, label_y = .lab$label.y,
              hjust = .lab$hjust, vjust = .lab$vjust, align = align,
              rel_widths = widths, rel_heights = heights,
              legend = legend, common.legend.grob = legend.grob
              )




  if(length(res) == 1) res <- res[[1]]

  class(res) <- c(class(res), "ggarrange")
  res
}



.get_layout <- function(ncol, nrow, nb.plots){
  if(!is.null(ncol) & !is.null(nrow)){}
  else if(!is.null(ncol)){
    if(ncol == 1) nrow = nb.plots
  }
  else if(!is.null(nrow)){
    if(nrow == 1) ncol = nb.plots
  }
  list(ncol = ncol, nrow = nrow)
}

# Compute number of plots per page
.nbplots_per_page <- function(ncol = NULL, nrow = NULL){

  if(!is.null(ncol) & !is.null(nrow))
    ncol * nrow
  else if(!is.null(ncol))
    ncol
  else if(!is.null(nrow))
    nrow
  else Inf
}


.plot_grid <- function(plotlist, legend = "top", common.legend.grob = NULL,  ... ){


  res <- cowplot::plot_grid(plotlist = plotlist, ...)
  if(is.null(common.legend.grob)) return(res)
  else {
    leg <- common.legend.grob
    lheight <- sum(leg$height)
    lwidth <- sum(leg$width)
  }

  arrangeGrob <- gridExtra::arrangeGrob
  unit.c <- grid::unit.c
  .unit <- grid::unit(1, "npc")

  res <- switch(legend,
                top = arrangeGrob(leg, res, ncol = 1,
                                  heights = unit.c(lheight, .unit - lheight)),
                bottom = arrangeGrob(res, leg, ncol = 1,
                                     heights = unit.c(unit(1, "npc") - lheight, lheight)),
                left = arrangeGrob(leg, res, ncol = 2,
                                   widths = unit.c(lwidth, .unit - lwidth)),
                right = arrangeGrob(res, leg, ncol = 2,
                                    widths = unit.c(.unit - lwidth, lwidth))
                )

  p <- cowplot::ggdraw() + cowplot::draw_grob(grid::grobTree(res))
  p

}

# update label parameters for cowplot::plot_grid()
.update_label_pms <- function(font.label,
                             label.x = 0, label.y = 1, hjust = -0.5, vjust = 1.5)
  {

  .font <- list(size = 14, color = "black", face = "bold", family = NULL)
  new.font.names <- names(font.label)
  for(i in new.font.names) .font[[i]] <- font.label[[i]]

  pms <- .font
  list(
    size = pms$size,
    family = pms$family,
    face = pms$face,
    color = pms$color,
    label.x = label.x, label.y = label.y,
    hjust = hjust, vjust = vjust
  )
}
