#
# 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/
#

## Instructions:

## * Change the radioButton to a selectInput  interface.
## * I have added an interface that will let you specify how many samples you want.  Add code in the server to 
## use this selection.

library(shiny)
library(ggplot2)
library(gridExtra)


# Define UI for application that draws a histogram
ui <- fluidPage(
    
    # Application title
    titlePanel("Random distribution generation"),
    
    # Sidebar with a slider input for number of bins 
    sidebarLayout(
        sidebarPanel(
            sliderInput("bins",                        "Number of bins:",
                        min = 1,
                        max = 50,
                        value = 30),
            selectInput("type",label="Select form of distribution",
                        choices=c("normal","uniform")),
            numericInput("number","Number of samples",500,min=100,max=10000,step=100,width='100%'),
            
            
            tags$a("Link to wikipedia",href="http://en.wikipedia.org"),
            tags$p(),
            tags$hr(),
            tags$a( tags$img(src="https://upload.wikimedia.org/wikipedia/en/c/c9/Michigan_Technological_University_logo.svg"),
                    href="http://mtu.edu")
        ),
        
        # Show a plot of the generated distribution
        mainPanel(
            h1("Histogram and normal q-q plot"),
            plotOutput("distPlot")
        )
    )
)



# Define server logic required to draw a histogram
server <- function(input, output) {
    
  
  
  output$distPlot <- renderPlot({
    n <- input$number
    
    if(input$type=="uniform")
    {
      x    <- runif(n)
    } else if(input$type=="normal")
    {
      x    <-  rnorm(n)
    } else{
      x <- 1:n
    }
    
    # draw the histogram with the specified number of bins
    a <- as.data.frame(x) |> ggplot(aes(x=x)) +geom_histogram(bins=input$bins,fill="orange2",color="black") + theme_bw()
    b <- as.data.frame(x) |> ggplot(aes(sample=x)) + geom_qq() + theme_bw()
    grid.arrange(a,b,ncol=2)
    
  })
}
# Run the application 
shinyApp(ui = ui, server = server)