#
# 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)
library(ggplot2)

# Define UI for random distribution app ----
ui <- fluidPage(
  
  sidebarPanel(
      # Input: Select the random distribution type ----
      radioButtons("dist", "Distribution type:",
                   c("Normal" = "norm",
                     "Unif" = "unif")
                   ),
      sliderInput("n",
                  "Sample Size",
                  min = 1,
                  max = 10000,
                  value = 50),
      sliderInput("bins",
                  "Histogram bin count:",
                  min = 1,
                  max = 300,
                  value = 30),
      sliderInput("bw",
                  "Density Bandwidth",
                  min = 0, 
                  max = 1,
                  value = 0.5),
  
  # Normal distribution parameters
  conditionalPanel(
    condition = "input.dist == 'norm'",
    sliderInput("mean", 
                "mean",
                min = -100,
                max = 100,
                value = 0),
    sliderInput("sdev",
                "sdev",
                min = 0,
                max = 100,
                value = 1)
  ),
  
  # Normal distribution parameters
  conditionalPanel(
    condition = "input.dist == 'unif'",
    sliderInput("range", 
                "Minimum and Maximum",
                min = -100,
                max = 100,
                value = c(0, 10)
                )
    )
  ),
  
  mainPanel(
    
    # Output: Tabset w/ plot, summary, and table ----
    plotOutput("histPlot")
    )
)

# Define server logic required to draw a histogram
server <- function(input, output) {
  output$histPlot <- renderPlot({
    
    random_sample <- data.frame(switch(input$dist,
                                       'norm' = rnorm(n = input$n, mean = input$mean, sd = input$sdev),
                                       'unif' = runif(n = input$n, min = input$range[1], max = input$range[2])
                                       )
                                )
    
    names(random_sample) <- c('x')

    ggplot(data = random_sample, aes(x = x)) +
      geom_histogram(aes(y=..density..), bins = input$bins) +
      geom_vline(xintercept = mean(random_sample$x), color = 'red', linetype = 'dotted', size = 1) +
      geom_density(bw = input$bw) # +
      #stat_function(fun = dnorm, n = 101, args = list(mean = 0, sd = 1), color = 'red')
      
  })
}

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