server.R

# This is the server logic for a Shiny web application.
# You can find out more about building applications with Shiny here:
#
# http://shiny.rstudio.com
#

library(shiny)
library(shinydashboard)
library(data.table)
library(DT)
shinyServer(function(input, output) {
  vals<-reactiveValues()
  vals$Data<-data.table(
    Brands=paste0("Brand",1:10),
    Forecasted_Growth=sample(1:20,10),
    Last_Year_Purchase=round(rnorm(10,1000,1000)^2),
    Contact=paste0("Brand",1:10,"@email.com")
  )

  output$MainBody<-renderUI({
    fluidPage(
      box(width=12,
      h3(strong("Actions on datatable with buttons"),align="center"),
      hr(),
      column(6,offset = 6,
      HTML('<div class="btn-group" role="group" aria-label="Basic example">'),
      actionButton(inputId = "Add_row_head",label = "Add a new row"),
      actionButton(inputId = "Del_row_head",label = "Delete selected rows"),
      actionButton(inputId = "Compare_row_head",label = "Compare selected rows"),
      HTML('</div>')
      ),
      
      column(12,dataTableOutput("Main_table")),
      tags$script(HTML('$(document).on("click", "input", function () {
  var checkboxes = document.getElementsByName("row_selected");
  var checkboxesChecked = [];
  for (var i=0; i<checkboxes.length; i++) {

     if (checkboxes[i].checked) {
        checkboxesChecked.push(checkboxes[i].value);
     }
  }
  Shiny.onInputChange("checked_rows",checkboxesChecked);
      })')),
      tags$script("$(document).on('click', '#Main_table button', function () {
                    Shiny.onInputChange('lastClickId',this.id);
                    Shiny.onInputChange('lastClick', Math.random())
  });")

      )
      )
  })
  
  output$Main_table<-renderDataTable({
    DT=vals$Data
    DT[["Select"]]<-paste0('<input type="checkbox" name="row_selected" value="Row',1:nrow(vals$Data),'"><br>')
    
    DT[["Actions"]]<-
      paste0('
             <div class="btn-group" role="group" aria-label="Basic example">
                <button type="button" class="btn btn-secondary delete" id=delete_',1:nrow(vals$Data),'>Delete</button>
                <button type="button" class="btn btn-secondary modify"id=modify_',1:nrow(vals$Data),'>Modify</button>
             </div>
             
             ')
    datatable(DT,
    escape=F)}
  )
  
  observeEvent(input$Add_row_head,{
    new_row=data.frame(
      Brands="NewBrand",
      Forecasted_Growth=sample(1:20,1),
      Last_Year_Purchase=round(rnorm(1,1000,1000)^2),
      Contact="NewBrand@email.com")
      vals$Data<-rbind(vals$Data,new_row)
      })
  
  
  observeEvent(input$Del_row_head,{
               row_to_del=as.numeric(gsub("Row","",input$checked_rows))
               
               vals$Data=vals$Data[-row_to_del]}
               )
  
  
  
  ###Brand visualisation 
  observeEvent(input$Compare_row_head,{
    row_to_del=as.numeric(gsub("Row","",input$checked_rows))
    number_brands=length(row_to_del)
    vals$fake_sales=data.table(
      month=rep(1:12,number_brands),sales=round(rnorm(12*number_brands,1000,1000)^2)/12,
      Brands=rep(vals$Data[row_to_del,Brands],each=12)
    )
    vals$fake_sales[,Brands:=as.factor(Brands)]
    showModal(fake_sales_modal)
    }
  )
  
  
  fake_sales_modal<-modalDialog(
    fluidPage(
      h3(strong("Monthly sales of selected brands"),align="center"),
      plotOutput('sales_plot')
    ),
    size="l"
  )
  
  output$sales_plot<-renderPlot({
    require(ggplot2)
    ggplot(vals$fake_sales,aes(x=month,y=sales,color=Brands))+geom_line()
  })
  
  ##Managing in row deletion
  modal_modify<-modalDialog(
    fluidPage(
      h3(strong("Row modification"),align="center"),
      hr(),
      dataTableOutput('row_modif'),
      actionButton("save_changes","Save changes"),
      
      tags$script(HTML("$(document).on('click', '#save_changes', function () {
var list_value=[]
for (i = 0; i < $( '.new_input' ).length; i++)
                       {
                          list_value.push($( '.new_input' )[i].value)



                       }

Shiny.onInputChange('newValue', list_value)
  });"))
    ),
    size="l"
  )
  
  
  observeEvent(input$lastClick,
               {
                 if (input$lastClickId%like%"delete")
                 {
                   row_to_del=as.numeric(gsub("delete_","",input$lastClickId))
                   vals$Data=vals$Data[-row_to_del]
                 }
                 else if (input$lastClickId%like%"modify")
                 {
                   showModal(modal_modify)
                 }
               }
               )

  output$row_modif<-renderDataTable({
      selected_row=as.numeric(gsub("modify_","",input$lastClickId))
      old_row=vals$Data[selected_row]
      row_change=list()
      for (i in colnames(old_row))
      {
        if (is.numeric(vals$Data[[i]]))
        {
          row_change[[i]]<-paste0('<input class="new_input" type="number" id=new_',i,'><br>')
        }
        else
        row_change[[i]]<-paste0('<input class="new_input" type="text" id=new_',i,'><br>')
      }
      row_change=as.data.table(row_change)
      setnames(row_change,colnames(old_row))
      DT=rbind(old_row,row_change)
      rownames(DT)<-c("Current values","New values")
      DT
      
    },escape=F,options=list(dom='t',ordering=F),selection="none"
    )

  
  observeEvent(input$newValue,
              {
                newValue=lapply(input$newValue, function(col) {
                  if (suppressWarnings(all(!is.na(as.numeric(as.character(col)))))) {
                    as.numeric(as.character(col))
                  } else {
                    col
                  }
                })
                DF=data.frame(lapply(newValue, function(x) t(data.frame(x))))
                colnames(DF)=colnames(vals$Data)
                vals$Data[as.numeric(gsub("modify_","",input$lastClickId))]<-DF
                
              }
              )
  



})