library(ggplot2)
library(xtable)
library(gridExtra)

# Define a function to generate a PDF file
get_pdf <- function(data, row_var, col_var) {
  # Create a data frame for plotting
  df <- data.frame(row = row_var, col = col_var, value = with(data, table(get(row_var), get(col_var))))
  
  # Initialize lists for plots and tables
  plots <- list()
  tables <- list()
  
  # Plot the bar chart
  p <- ggplot(df, aes(x = row, y = value)) + 
    geom_bar(stat = "identity") + 
    theme(axis.text.x = element_text(angle = 90, hjust = 1))
  plots[[1]] <- p
  
  # Create a table from the data frame
  t <- xtable(df, caption = "Table", align = "l")
  tables[[1]] <- t
  
  # Arrange the plots and tables in a grid
  grid.arrange(t, plots[[1]], ncol = 2)
  
  # Generate the PDF file
  pdf(file = "RES_Insights_Outputs_", onefile = TRUE)
  grid.arrange(t, plots[[1]], ncol = 2)
  dev.off()
}

ui <- navbarPage("My Shiny App",
                 tabPanel("Insights",
                          sidebarPanel(
                            fileInput("file1", "Choose input data"),
                            selectInput("filtervar", "Select Filter Variable", NULL),
                            checkboxGroupInput("filteroptions", "Filter Options", NULL)
                            ),
                          mainPanel(
                            tabsetPanel(id = "mytabs",
                                        tabPanel("Data", tableOutput("table.output"))
                            )
                          )
                 )
)

server <- function(input, output, session) {
  values <- reactiveValues(data = NULL)
  
  observe({
    file <- input$file1
    
    if (is.null(file)) return()
    
    values$data <- fread(file$datapath)
  })
  
  observe({
    data <- isolate(values$data)
    var <- input$filtervar
    filterOptions <- input$filteroptions
    
    if (is.null(data) || is.null(var) || var == "") {
      return()
    } else if (is.null(filterOptions)) {
      values$data
    } else {
      
      # Convert the value to numeric if necessary
      if (is.factor(data[[var]])) {
        options <- levels(data[[var]])
      } else {
        options <- unique(data[order(data[[var]])])
      }
      
      # Filter the data based on the selected value
      filteredData <- data[.(values = filterOptions),]
      
      if (!is.null(filteredData)) {
        setkeyv(filteredData, var)
        values$data <- filteredData
      } else {
        values$data <- data
      }
    }
  })
  
  output$table.output <- renderTable({
    isolate({
      data <- values$data
      var <- input$filtervar
      filterOptions <- input$filteroptions
      
      if (is.null(data)) return()
      if (is.null(var) || var == "") return(data)
      
      # Convert the value to numeric if necessary
      if (is.factor(data[[var]])) {
        options <- levels(data[[var]])
      } else {
        options <- unique(data[order(data[[var]])])
      }
      
      # Filter the data based on the selected value
      filteredData <- data[.(values = filterOptions),]
      
      if (!is.null(filteredData)) {
        setkeyv(filteredData, var)
        return(filteredData)
      } else {
        return(data)
      }
    })
  })
  
  output$export <- downloadHandler(
    filename = function() {
      paste0("RES_Insights_Outputs_", Sys.Date(), ".pdf")
    },
    content = function(file) {
      get_pdf(values$data, names(values$data)[1], names(values$data)[2], file)
    }
  )
}

shinyApp(ui = ui, server = server)