sankey_plot_internal.R

#' Create the sankey Plot
#' @param dat1 dataframe
#' @param quant Quantitative variable
#' @keywords internal
sankey_plot_func <- function(dat1, quant){

  #This will tell us which column is the quantitative variable. We Set 'amount_award' as the qunatitative variable in the dataframe and retrieve the column number
  quant_var <- which(colnames(dat1) == quant)

  #We set the quantitative variable column to 'amount' for standardization
  colnames(dat1)[quant_var] <- "amount"

  #Get a dataframe that has only the variables that will be made into nodes in the sankey chart
  dat_nodes <- dat1[,-quant_var]

  #Create a list of nodes with their level in the sankey chart and assign them an ID
  nodes <- c()
  levels <- c()
  n <- 1
  for (i in colnames(dat_nodes)) {
    vals <- unique(dat_nodes[,i])[[1]]
    nodes <- append(nodes,  vals)
    levels <- append(levels, rep(n, length(vals)))
    n <- n+1

  }
  node_df <- data.frame(nodes, levels)
  node_df$ID <- seq(from = 0 , nrow(node_df)-1)


  #We now create the dataframe with the appropriate colors for the sankey nodes
  node_colors <- RColorBrewer::brewer.pal(n = 12, name = "Set3")
  add_color_df <- data.frame(node_colors, 1:12)
  colnames(add_color_df)[2] <- "ID"

  #add the colors to our node dataframe
  node_df <- left_join(node_df, add_color_df, by = c("levels" = "ID"))

  #If node is null make it red #d11100
  node_df[is.na(node_df$nodes),"node_colors"] <- '#d11100'


  #Go through all of our columns and retrieve the values connecting nodes
  source <- c()
  target <- c()
  amount <- c()
  for (i in 1:(length(colnames(dat_nodes)) - 1) ) {
    col1 <- colnames(dat_nodes)[i]
    col2 <- colnames(dat_nodes)[i+1]

    dat2 <- dat1 %>%
      group_by(.dots = c(col1,col2)) %>%
      summarise(amount = sum(amount))

    colnames(dat2)[1] <- "nodes"
    dat2 <- left_join(dat2, node_df[node_df$levels==i,c(1,3)], by = "nodes")
    colnames(dat2)[colnames(dat2)=="ID"] <- "Source"
    dat2 <- dat2[,2:4]
    colnames(dat2)[1] <- "nodes"
    dat2 <- left_join(dat2, node_df[node_df$levels==(i+1),c(1,3)], by = "nodes")
    colnames(dat2)[colnames(dat2)=="ID"] <- "Target"
    dat2 <- dat2[,2:4]

    source <- append(source, dat2$Source)
    target <- append(target, dat2$Target)
    amount <- append(amount, dat2$amount)

  }

  #With the node df and the connections we can now plot our sankey chart
  fig <- plot_ly(
    type = "sankey",
    orientation = "h",

    node = list(
      label = node_df$nodes,
      color = node_df$node_colors,
      pad = 15,
      thickness = 20,
      line = list(
        color = "black",
        width = 0.5
      )
    ),

    link = list(
      source = source,
      target = target,
      value =  amount
    )
  )
  fig <- fig %>% layout(
    title = "",
    font = list(
      size = 10
    )
  )
  fig
}