Save the path history to the radio button

[LeeKayn]

I am designing an R Shiny app, and I have been able to display the selected file name back to the radio button. However, I have tried many methods, including getting help from an AI bot, but it seems to not work well. I want to be able to visualize again after clicking on the radio button with the file name, without having to select the file again from the beginning. Here is my server.R code:

library(shiny)
library(ggplot2)
library(dplyr)
library(readr)
library(lubridate)

selectedFileNames <- reactiveVal(character(0))

shinyServer(function(input, output, session) {
  data <- reactive({
    req(input$file)
    selectedFileName <- input$file$name

    if (!(selectedFileName %in% selectedFileNames())) {
      selectedFileNames(c(selectedFileNames(), selectedFileName))
    }
    
    read.csv(input$file$datapath, stringsAsFactors = FALSE)
  })
  
  observe({
    updateRadioButtons(session, "selectedOption", choices = c("", selectedFileNames()), selected = input$selectedOption)
  })
  
  
  filteredData <- reactive({
    data_filtered <- data()
    date_range <- input$dateRange
    if (!is.null(date_range)) {
      start_date <- as.POSIXct(date_range[1], format = "%Y-%m-%d", tz = "UTC")
      end_date <- as.POSIXct(date_range[2], format = "%Y-%m-%d", tz = "UTC")
      data_filtered <- data_filtered %>%
        filter(between(as.POSIXct(Start.Time), start_date, end_date))
    }
    data_filtered
  })
  
  output$userSearchPlot <- renderPlot({
    ggplot(filteredData(), aes(x = as.Date(Start.Time), fill = factor(User))) +
      geom_bar() +
      labs(title = "Number of User Searches Over Time",
           x = "Date",
           y = "Number of Searches",
           fill = "User") +
      theme_minimal() +
      scale_x_date(date_labels = "%Y-%m-%d", date_breaks = "1 day") +
      theme(axis.text.x = element_text(angle = 90, hjust = 1))
  })
  
  output$summaryText <- renderPrint({
    summary_data <- filteredData() %>%
      group_by(date = as.Date(Start.Time)) %>%
      summarise(NumUsers = n_distinct(User), NumSearches = n()) %>%
      as.data.frame()
    
    summary_label <- "Summary of User Searches Over Time"
    
    # Thêm tiêu đề cho các cột
    colnames(summary_data) <- c("Date", "Number of User", "Number of Searcher")

    cat(summary_label, "\n")
    print(summary_data)
  })
})