#' Add forceAtlas2

#' 

#' Implementation of \href{http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0098679}{forceAtlas2}.

#' 

#' @inheritParams sg_nodes

#' @param proxy An object of class \code{sigmajsProxy} as returned by \code{\link{sigmajsProxy}}.

#' @param delay Milliseconds after which the layout algorithm should stop running.

#' @param data \code{data.frame} holding \code{delay} column.

#' @param cumsum Whether to compute the cumulative sum of the delay.

#' @param ... Any parameter, see \href{https://github.com/jacomyal/sigma.js/tree/master/plugins/sigma.layout.forceAtlas2}{official documentation}.

#' @param refresh Whether to refresh the graph after node is dropped, required to take effect.

#' 

#'

#' @section Functions:

#' \itemize{

#'	\item{\code{sg_force}, \code{sg_force_start} starts the forceAtlas2 layout}

#'	\item{\code{sg_force_stop} stops the forceAtlas2 layout after a \code{delay} milliseconds}

#'	\item{\code{sg_force_restart_p} proxy to re-starts (\code{kill} then \code{start}) the forceAtlas2 layout, the options you pass to this function are applied on restart. If forceAtlas2 has not started yet it is launched.}

#'	\item{\code{sg_force_start_p} proxy to start forceAtlas2.}

#'	\item{\code{sg_force_stop_p} proxy to stop forceAtlas2.}

#'	\item{\code{sg_force_kill_p} proxy to ompletely stops the layout and terminates the assiociated worker. You can still restart it later, but a new worker will have to initialize.}

#'	\item{\code{sg_force_config_p} proxy to set configurations of forceAtlas2.}

#'	\item{\code{sg_force_restart} Restarts (kills then starts) forceAtlas2 at given delay.}

#' }

#' 

#' @details The delay helps for build dynamic visualisations where nodes and edges do not appear all at the same time.

#' How the delay works depends on the \code{cumsum} parameter. if \code{TRUE} the function computes the cumulative sum

#' of the delay to effectively add each row one after the other: delay is thus applied at each row (number of seconds to wait

#' before the row is added *since the previous row*). If \code{FALSE} this is the number of milliseconds to wait before the node or

#' edge is added to the visualisation; \code{delay} is used as passed to the function.

#' 

#' @examples

#' nodes <- sg_make_nodes(50)

#' edges <- sg_make_edges(nodes, 100)

#'

#' sigmajs() %>%

#'   sg_nodes(nodes, id, label, size) %>%

#'   sg_edges(edges, id, source, target) %>% 

#'   sg_force() %>% 

#'   sg_force_stop() # stop force after 5 seconds

#' 

#' @return Their first arguments, either \code{sg} or \code{proxy}.

#' 

#' @seealso \href{https://github.com/jacomyal/sigma.js/tree/master/plugins/sigma.layout.noverlap}{official documentation}

#'

#' @name force

#' @export

sg_force <- function(sg, ...) {

}

#' @rdname force

#' @export

sg_force_start <- sg_force

#' @rdname force

#' @export

sg_force_stop <- function(sg, delay = 5000) {

}

#' @rdname force

#' @export

sg_force_restart_p <- function(proxy, ..., refresh = TRUE) {

}

#' @rdname force

#' @export

sg_force_restart <- function(sg, data, delay, cumsum = TRUE) {

  # build data

} 

#' @rdname force

#' @export

sg_force_start_p <- function(proxy, ..., refresh = TRUE) {

}

#' @rdname force

#' @export

sg_force_stop_p <- function(proxy) {

}

#' @rdname force

#' @export

sg_force_kill_p <- function(proxy) {

}

#' @rdname force

#' @export

sg_force_config_p <- function(proxy, ...) {

}