# ---- Robust package setup ----

options(repos = c(CRAN = "https://cran.rstudio.com"))

required_packages <- c(
  "teal",
  "teal.widgets",
  "shiny",
  "ggplot2"
)

installed_packages <- rownames(installed.packages())
missing_packages <- setdiff(required_packages, installed_packages)

if (length(missing_packages) > 0) {
  install.packages(
    missing_packages,
    type = "binary",
    dependencies = TRUE
  )
}

library(teal)
library(teal.widgets)
library(shiny)
library(ggplot2)

data <- teal_data(
  IRIS = iris,
  MTCARS = mtcars
)

plot_module <- function(label = "Plot") {
  module(
    label = label,
    
    ui = function(id) {
      ns <- NS(id)
      
      standard_layout(
        encoding = tagList(
          selectInput(
            ns("dataset"),
            "Choose a dataset:",
            choices = c("IRIS", "MTCARS")
          )
        ),
        output = plotOutput(ns("plot"), height = "80vh")
      )
    },
    
    server = function(id, data) {
      moduleServer(id, function(input, output, session) {
        
        output$plot <- renderPlot({
          
          df <- data()[[input$dataset]]
          
          # Keep numeric columns
          num_df <- df[, sapply(df, is.numeric), drop = FALSE]
          req(ncol(num_df) >= 2)
          
          x_name <- names(num_df)[1]
          y_name <- names(num_df)[2]
          
          ggplot(num_df, aes_string(x = x_name, y = y_name)) +
            geom_point(color = "steelblue", size = 2) +
            labs(
              title = paste("First Two Numeric Variables:", input$dataset),
              x = x_name,
              y = y_name
            ) +
            theme_minimal()
        })
      })
    }
  )
}

app <- init(
  data = data,
  modules = modules(plot_module())) %>%  
  
  modify_title("Basic Teal Demo App") %>% 
  modify_header("My first teal app") %>% 
  modify_footer("Powered by teal + shiny")

shinyApp(app$ui, app$server)