controlLabel <- function(controlName, label) {
  label %AND% tags$label(class = "control-label", `for` = controlName, label)
}


# Before shiny 0.9, `selected` refers to names/labels of `choices`; now it
# refers to values. Below is a function for backward compatibility. It also
# coerces the value to `character`.
validateSelected <- function(selected, choices, inputId) {
  # this line accomplishes two tings:
  #   - coerces selected to character
  #   - drops name, otherwise toJSON() keeps it too
  selected <- as.character(selected)
  # if you are using optgroups, you're using shiny > 0.10.0, and you should
  # already know that `selected` must be a value instead of a label
  if (needOptgroup(choices)) return(selected)

  if (is.list(choices)) choices <- unlist(choices)

  nms <- names(choices)
  # labels and values are identical, no need to validate
  if (identical(nms, unname(choices))) return(selected)
  # when selected labels instead of values
  i <- (selected %in% nms) & !(selected %in% choices)
  if (any(i)) {
    warnFun <- if (all(i)) {
      # replace names with values
      selected <- unname(choices[selected])
      warning
    } else stop  # stop when it is ambiguous (some labels == values)
    warnFun("'selected' must be the values instead of names of 'choices' ",
            "for the input '", inputId, "'")
  }
  selected
}


# generate options for radio buttons and checkbox groups (type = 'checkbox' or
# 'radio')
generateOptions <- function(inputId, choices, selected, inline, type = 'checkbox') {
  # generate a list of <input type=? [checked] />
  options <- mapply(
    choices, names(choices),
    FUN = function(value, name) {
      inputTag <- tags$input(
        type = type, name = inputId, value = value
      )
      if (value %in% selected)
        inputTag$attribs$checked <- "checked"

      # If inline, there's no wrapper div, and the label needs a class like
      # checkbox-inline.
      if (inline) {
        tags$label(class = paste0(type, "-inline"), inputTag, tags$span(name))
      } else {
        tags$div(class = type,
          tags$label(inputTag, tags$span(name))
        )
      }
    },
    SIMPLIFY = FALSE, USE.NAMES = FALSE
  )

  div(class = "shiny-options-group", options)
}


# Takes a vector or list, and adds names (same as the value) to any entries
# without names. Coerces all leaf nodes to `character`.
choicesWithNames <- function(choices) {
  # Take a vector or list, and convert to list. Also, if any children are
  # vectors with length > 1, convert those to list. If the list is unnamed,
  # convert it to a named list with blank names.
  listify <- function(obj) {
    # If a list/vector is unnamed, give it blank names
    makeNamed <- function(x) {
      if (is.null(names(x))) names(x) <- character(length(x))
      x
    }

    res <- lapply(obj, function(val) {
      if (is.list(val))
        listify(val)
      else if (length(val) == 1 && is.null(names(val)))
        as.character(val)
      else
        makeNamed(as.list(val))
    })

    makeNamed(res)
  }

  choices <- listify(choices)
  if (length(choices) == 0) return(choices)

  # Recurse into any subgroups
  choices <- mapply(choices, names(choices), FUN = function(choice, name) {
    if (!is.list(choice)) return(choice)
    if (name == "") stop('All sub-lists in "choices" must be named.')
    choicesWithNames(choice)
  }, SIMPLIFY = FALSE)

  # default missing names to choice values
  missing <- names(choices) == ""
  names(choices)[missing] <- as.character(choices)[missing]

  choices
}