show file2 browse button after pop up message

[MadDeveloper]

Hello all,

I'm writing an rshiny program, where I need to upload multiple excel files in 3 different batches. For that I have 3 fileinput() functions(for e.g., file1, file2 and file3) in the intial page load.

But, I don't want to display all three in the intial page load.

During the Intial load, it should display only file1, after sucessfull load it should display a pop-up message, after clicking on the "OK" it have to show file2 and disable editing of file1 browse button. How can I achieve this functionality? I'm loosing myself as I'm new to Rshiny

Following is the code I have been trying:

ui.r

ui <- fluidPage(
  
  # App title ----
  titlePanel("Uploading Files"),
  
  # Sidebar layout with input and output definitions ----
  sidebarLayout(
    
    # Sidebar panel for inputs ----
    sidebarPanel(
      
      # Input: Select a file ----
      fileInput("file1", "Choose file1 for upload",  multiple = TRUE, accept = c(".xlsx", ".xls", ".csv")),
      tags$hr(),
      conditionalPanel(condition = "input.file == 'f1loadcompleted'", 
                       fileInput("file2", "Choose 2 files for upload", multiple = TRUE, accept = c(".xlsx", ".xls", ".csv"))),
      tags$hr(),
       conditionalPanel(condition = "input.file == 'f1 & f2 load completed'", 
                       fileInput("file3", "Choose  3 files for upload", multiple = TRUE, accept = c(".xlsx", ".xls", ".csv"))),
     tags$hr(),
    ),
    
    # Main panel for displaying outputs ----
    mainPanel(
      tableOutput("contents")
    )
  )
)

server.r

server <- function(input, output) {
  
  output$contents <- renderTable({
                                                     req(input$file1)
                                                      df1 = input$file1
                                                      df1$SubString <- data.frame(substring(df1$name, 1, 3))
                                          # functionality of f1 which is working absolutely fine
                                          #
                                          shinyalert("Please load SCORE INFORMATION files", "Originals load completed", type = "info")
                                              
                                              file <- "f1loadcompleted"
                                              if(input$file == "f1loadcompleted"){ 
                                               file <- input$file2
                                                }
                                              req(input$f2)
                                              df2= input$file2
                                              df2$SubString <- data.frame(substring(df2$name, 1, 3))
                                              
                                             
                                          )}}