## ---- include = FALSE---------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----setup--------------------------------------------------------------------
library(scenes)

## ----UIs----------------------------------------------------------------------
# ui1 loads if none of the requirements are met.
ui1 <- shiny::tagList(
  shiny::p("This is UI 1."),
  shiny::a("Add '?code' to the URL to see UI 2.", href = "?code")
)

# ui2 allows us to create the cookie requirement for ui3.
ui2 <- cookies::add_cookie_handlers(
  shiny::tagList(
    shiny::p("This is UI 2."),
    shiny::actionButton("cookie_simple", "Store Simple Cookie"),
    shiny::p("Press the button to see UI 3.")
  )
)

# ui3 allows us to update that cookie to one that will pass validation.
ui3 <- cookies::add_cookie_handlers(
  shiny::tagList(
    shiny::p("This is UI 3."),
    shiny::actionButton("cookie_valid", "Store Valid Cookie"),
    shiny::p("Press the button to see UI 4.")
  )
)

# ui4 only loads when everything is all set. It has a button to reset things.
ui4 <- cookies::add_cookie_handlers(
  shiny::tagList(
    shiny::p("This is UI 4."),
    shiny::actionButton("reset", "Reset"),
    shiny::p("Press the button to go back to UI 2.")
  )
)

## ----ui4-validation-----------------------------------------------------------
our_cookie_validator <- function(cookie_value, acceptable) {
  cookie_value == acceptable
}

## ----scene4-------------------------------------------------------------------
scene4 <- set_scene(
  ui4,
  req_has_cookie(
    cookie_name = "our_cookie",
    validation_fn = our_cookie_validator,
    acceptable = "good value" # We can pass variables through to our validator.
  )
)

## ----scene3-------------------------------------------------------------------
scene3 <- set_scene(
  ui3,
  req_has_cookie(
    cookie_name = "our_cookie"
  )
)

## ----scene2-------------------------------------------------------------------
scene2 <- set_scene(
  ui2,
  req_has_query("code")
)

## ----scene1-------------------------------------------------------------------
scene1 <- set_scene(
  ui1
)

## ----change-------------------------------------------------------------------
ui <- change_scene(
  scene4,
  scene3,
  scene2,
  scene1
)

## ----shiny, eval = FALSE------------------------------------------------------
#  # Any UI that the user sees will use this
#  # shared server backend.
#  server <- function(input, output, session) {
#    # If they press the button in ui2, save a cookie and reload.
#    shiny::observeEvent(
#      input$cookie_simple,
#      {
#        cookies::set_cookie("our_cookie", "bad value")
#        session$reload()
#      }
#    )
#  
#    # If they press the button in ui3, save a "valid" cookie and reload.
#    shiny::observeEvent(
#      input$cookie_valid,
#      {
#        cookies::set_cookie("our_cookie", "good value")
#        session$reload()
#      }
#    )
#  
#    # If they press the reset button in ui4, delete the cookie and reload.
#    shiny::observeEvent(
#      input$reset,
#      {
#        cookies::remove_cookie("our_cookie")
#        session$reload()
#      }
#    )
#  }
#  
#  shiny::shinyApp(
#    ui = ui,
#    server = server
#  )