Code Editor for app.R

library(shiny)
library(tidyverse)
library(ggplot2)

source("utils.R")

ui <- fluidPage(
  titlePanel("Dynamic Data Visualization"),
  
  sidebarLayout(
    sidebarPanel(
      textInput("url", "Data URL:", 
                value = "https://raw.githubusercontent.com/mwaskom/seaborn-data/master/penguins.csv"),
      numericInput("n_rows", "Number of rows to display:", 
                   min = 1, max = 1000, value = 10),
      checkboxInput("shuffle", "Randomly shuffle data", FALSE),
      selectInput("var1", "Select first variable:", choices = NULL),
      selectInput("var2", "Select second variable (optional):", 
                 choices = NULL, selected = NULL),
      actionButton("update", "Update Data")
    ),
    
    mainPanel(
      h4("Data Preview:"),
      tableOutput("data_preview"),
      h4("Visualization:"),
      plotOutput("plot")
    )
  )
)

server <- function(input, output, session) {
  # Reactive data fetch and processing
  data <- eventReactive(input$update, {
    fetch_and_process_data(input$url)
  }, ignoreNULL = FALSE)
  
  # Update variable selection choices when data changes
  observe({
    df <- data()
    if (!is.null(df)) {
      updateSelectInput(session, "var1", 
                       choices = c("None" = "", colnames(df)))
      updateSelectInput(session, "var2", 
                       choices = c("None" = "", colnames(df)))
    }
  })
  
  # Prepare data for display
  display_data <- reactive({
    df <- data()
    if (is.null(df)) return(NULL)
    
    if (input$shuffle) {
      df <- df[sample(nrow(df)), ]
    }
    
    head(df, input$n_rows)
  })
  
  # Data preview output
  output$data_preview <- renderTable({
    display_data()
  })
  
  # Plot output
  output$plot <- renderPlot({
    df <- data()
    if (is.null(df)) return(NULL)
    if (input$var1 == "") return(NULL)
    
    create_visualization(df, input$var1, input$var2)
  })
}

shinyApp(ui = ui, server = server)