library(shiny)
library(miniUI)

myGadgetFunc <- function(inputValue1, inputValue2) {
  ui <- miniPage(
    ## Define layout, inputs, outputs, etc.
  )
  
  server <- function(input, output, session) {
    # Define reactive expressions, outputs, etc.
    # And then 
    stopApp(returnValue)
  }
  runGadget(ui, server)
}

  ui <- miniPage(
    gadgetTitleBar("My Gadget"),
    miniContentPanel(
      # Define layout, inputs, outputs
    )
  )

  server <- function(input, output, session) {
    # Define reactive expressions, outputs, etc.

    # When the Done button is clicked, return a value
    observeEvent(input$done, {
      returnValue <- ...
      stopApp(returnValue)
    })
  }

regexTest = function(pattern="night", 
                     x = "We can turn day into night with this Gadget",
                     replace = "day") {
  
  ui = miniPage(
    gadgetTitleBar("Basic gsub tester"),
    miniContentPanel(
      textInput("text","Text:", x),
      textInput('pattern','Pattern to replace:', pattern),
      textInput("replacement","Text to substitute", replace),
      textOutput("out")
    )
  )
  
  server = function(input, output, session) {
    output$out = renderText( gsub(pattern = input$pattern,
                                 replace = input$replacement, 
                                 x = input$text) )
    observeEvent(input$done, {
      returnValue <- input$pattern
      stopApp(returnValue)
    })
  }
  runGadget(ui, server)
}

ggbrush <- function(dframe, xvar, yvar, viewer=paneViewer()) {
  
  ui <- miniPage(
    gadgetTitleBar("Drag to select points"),
    miniContentPanel(
      # The brush="brush" argument means we can listen for
      # brush events on the plot using input$brush.
      plotOutput("plot", height = "100%", brush = "brush")
    )
  )
  
  server <- function(input, output, session) {
    
    # Render the plot
    output$plot <- renderPlot({
      # Plot the data with x/y vars indicated by the caller.
      ggplot(dframe, aes_string(xvar, yvar)) + geom_point()
    })
    
    # Handle the Done button being pressed.
    observeEvent(input$done, {
      # Return the brushed points. See ?shiny::brushedPoints.
      stopApp(brushedPoints(dframe, input$brush))
    })
  }

  runGadget(ui, server)
}

shinyFunction = function() {
  require(shiny)
  server <- function(input, output) {
    output$distPlot <- renderPlot({
      hist(rnorm(input$obs), col = 'darkgray', border = 'white')
    })
  }
  
  ui <- fluidPage(
    sidebarLayout(
      sidebarPanel(
        sliderInput("obs", "Number of observations:", min = 10, max = 500, value = 100)
      ),
      mainPanel(plotOutput("distPlot"))
    )
  )
  
  shinyApp(ui = ui, server = server)
}

shinyFunction = function() {
  runApp(system.file("MyPackage","shinyAppDir"))
}