#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#
# Find out more about building applications with Shiny here:
#
#    http://shiny.rstudio.com/
#

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(

  # Application title
  titlePanel(textOutput("title")),

  # Sidebar with a slider input for number of bins
  sidebarLayout(
    sidebarPanel(
      textInput("title",
                "Main title :",
                "Data visualization"),
      selectInput("data",
                  "Select data input :",
                  choices = c("Old Faithful Geyser Data" = "faithful",
                              "Iris Data" = "iris",
                              "Motor Trend Car Road Tests" = "mtcars",
                              "Normally distributed random numbers" = "random")),
      sliderInput("bins",
                  "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30),
      radioButtons("color",
                   "Color of bins:",
                   choices = c("Dark gray" = "darkgray",
                               "Orange" = "coral",
                               "Light green" = "lightgreen")),
      conditionalPanel(
        condition = "input.data == 'random'",
        sliderInput("randomN",
                    "Number of observations :",
                    value = 100,
                    min = 1, 
                    max = 500),
        numericInput("randomMean",
                     "Mean :",
                     value = 0),
        numericInput("randomSd",
                     "Standard deviation :",
                     value = 1),
        actionButton("updateRandom", label = "Simulate again")
      )
    ),

    # Show a plot of the generated distribution
    mainPanel(
      tabsetPanel(
        tabPanel(
          "Histogram",
          plotOutput("histogram"),
          textOutput("textBins")
        ),
        tabPanel(
          "Boxplot",
          plotOutput("boxplot"),
        ),
        tabPanel(
          "Table",
          tableOutput("table"),
        )
      )
    )
  )
)

# Define server logic required to draw a histogram
server <- function(input, output) {
  output$title <- renderText({
    input$title
  })

  datasetInput <- reactiveVal(label = "datasetInput")

  observe({
    datasetInput(switch(input$data,
                        "faithful" = faithful$waiting,
                        "iris" = iris$Petal.Length,
                        "mtcars" = mtcars$hp,
                        "random" = rnorm(n = input$randomN, mean = input$randomMean, sd = input$randomSd)))
  }, 
  label = "datasetInput observer")

  bindEvent(
    ## update datasetInput with random data
    observe(datasetInput(rnorm(n = input$randomN, mean = input$randomMean, sd = input$randomSd)), label = "button observer"), 
    ## only when update button is pressed
    input$updateRandom
  )

  output$histogram <- renderPlot({
    # generate bins based on input$bins from ui.R
    x    <- datasetInput()
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    # draw the histogram with the specified number of bins
    hist(x, breaks = bins, col = input$color, border = 'white')
  })

  output$textBins <- renderText({
    c("There are currently", input$bins, input$color, "bins.")
  })


  output$boxplot <- renderPlot({
    x    <- datasetInput()
    boxplot(x, col = input$color)
  })

  output$table <- renderTable({
    x    <- datasetInput()
    x
  })
}

# Run the application
shinyApp(ui = ui, server = server)