carousel.R

library(htmltools)
library(yaml)

# carousel displays a list of items w/ nav buttons
carousel <- function(id, duration, items) {
  index <- -1
  items <- lapply(items, function(item) {
    index <<- index + 1
    carouselItem(item$caption, item$image, item$link, index, duration)
  })
  
  indicators <- div(class = "carousel-indicators",
                    tagList(lapply(items, function(item) item$button))
  )
  items <- div(class = "carousel-inner",
               tagList(lapply(items, function(item) item$item))           
  )
  div(id = id, class="carousel carousel-dark slide", `data-bs-ride`="carousel",
      indicators,
      items,
      navButton(id, "prev", "Prevoius"),
      navButton(id, "next", "Next")
  )
}

# carousel item
carouselItem <- function(caption, image, link, index, interval) {
  id <- paste0("gallery-carousel-item-", index)
  button <- tags$button(type = "button", 
                        `data-bs-target` = "#gallery-carousel",
                        `data-bs-slide-to` = index,
                        `aria-label` = paste("Slide", index + 1)
  )
  if (index == 0) {
    button <- tagAppendAttributes(button,
                                  class = "active",
                                  `aria-current` = "true"                  
    )
  }
  item <- div(class = paste0("carousel-item", ifelse(index == 0, " active", "")),
              `data-bs-interval` = interval,
              a(href = link, img(src = image, class = "d-block  mx-auto border")),
              div(class = "carousel-caption d-none d-md-block",
                  tags$p(class = "fw-light", caption)
              )
  )
  list(
    button = button,
    item = item
  )                        
}

# nav button
navButton <- function(targetId, type, text) {
  tags$button(class = paste0("carousel-control-", type),
              type = "button",
              `data-bs-target` = paste0("#", targetId),
              `data-bs-slide` = type,
              span(class = paste0("carousel-control-", type, "-icon"),
                   `aria-hidden` = "true"),
              span(class = "visually-hidden", text)
  )
}