#
# 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:
##  Add a selection option using radioButtons in the sidebar that let's you choose between a normal and uniform (or other) distributions

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(
          
            radioButtons("distselect","Choose a distribution",
                         c("normal","uniform")),
            sliderInput("bins",
                        "Number of bins:",
                        min = 1,
                        max = 50,
                        value = 30),
            tags$a("Link to wikipedia",href="http://en.wikipedia.org"),
            tags$p(),
            tags$hr(),
            tags$img(src="https://upload.wikimedia.org/wikipedia/commons/1/14/Michigan_tech_univ_husky_logo.png",width=150)
        ),
        
        # 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({
    
    distchoice <- input$distselect
    if(distchoice=="normal")
    {
      x <- rnorm(1000)
    } else if(distchoice=="uniform"){
      
      x  <- runif(1000)
    }   else{
      x <- rnorm(1000)
    }
    # 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)