the-teacher/the_sortable_tree

# ----------------------------------------
# Restorable Helpers
# ----------------------------------------
@add_to_restorable_path = (node) ->
  if window.is_restorable_tree
    id = node.data('node-id')
    nested_tree_path_add(id)
    return true
  false

@remove_from_restorable_path = (node) ->
  if window.is_restorable_tree
    id = node.data('node-id')
    nested_tree_path_remove(id)
    return true
  false

# ----------------------------------------
# Main Helpers
# ----------------------------------------
@nested_tree_toggle = (button) ->
  if button.hasClass('minus')
    button.removeClass('minus').addClass('plus').html('+')
  else
    button.removeClass('plus').addClass('minus').html('–')

@append_children_to_node = (node, html) ->
  html = html.trim()
  item = node.children('.item')

  button = node.children('.item').children('.expand')

  if html.length is 0
    button.addClass 'empty'

  if html.length > 0
    item.after html
    nested_tree_toggle(button)
    add_to_restorable_path(node)

@upload_nodes_children = (node, expand_node_url) ->
  node_id    = node.data('node-id')
  tree       = $('.sortable_tree')
  ctrl_items = $('i.handle, b.expand', tree)

  $.ajax
    type:     'POST'
    dataType: 'html'
    data:     { id: node_id }
    url:      expand_node_url

    beforeSend: (xhr) ->
      ctrl_items.hide()
      window.skip_expandable_tree_hashchange = true

    success: (data, status, xhr) ->
      ctrl_items.show()
      append_children_to_node(node, data)

    error: (xhr, status, error) ->
      try
        console.log error

@init_expandable_tree = ->
  sortable_tree = $('ol.sortable_tree')
  return false if sortable_tree.length is 0

  window.is_restorable_tree         ||= false
  window.is_cookie_restoreable_tree   = sortable_tree.data('cookie_store') || sortable_tree.data('cookie-store')

  if window.is_cookie_restoreable_tree
    steps = $.cookie(TSTconst.cookie_name())
    _set_hash(TSTconst.hash_prefix() + steps) if steps

  expand_node_url = sortable_tree.data('expand_node_url') || sortable_tree.data('expand-node-url')

  # Now it's designed only for one tree
  restore_nested_tree(sortable_tree, expand_node_url) if window.is_restorable_tree

  sortable_tree.on 'click', '.expand.minus', (e) ->
    button = $ @
    node   = button.parent().parent()
    nested_tree_toggle(button)
    remove_from_restorable_path(node)
    node.children('.nested_set').hide()
    false

  sortable_tree.on 'click', '.expand.plus', (e) ->
    button     = $ @
    node       = button.parent().parent()
    nested_set = node.children('.nested_set')
    
    if nested_set.length is 0
      upload_nodes_children(node, expand_node_url)
    else
      nested_set.show()
      nested_tree_toggle(button)
      add_to_restorable_path(node)

    false

  true

$ -> init_expandable_tree()