module ActionText::PlainTextConversion

def break_if_nested_list(node, text)
  if list_node_depth_for_node(node) > 0
    "\n#{text}"
  else
    text
  end
end

def bullet_for_li_node(node)
  if list_node_name_for_li_node(node) == "ol"
    index = node.parent.elements.index(node)
    "#{index + 1}."
  else
    "•"
  end
end

def indentation_for_li_node(node)
  depth = list_node_depth_for_node(node)
  if depth > 1
    "  " * (depth - 1)
  end
end

def list_node_depth_for_node(node)
  node.ancestors.map(&:name).grep(/^[uo]l$/).count
end

def list_node_name_for_li_node(node)
  node.ancestors.lazy.map(&:name).grep(/^[uo]l$/).first
end

def node_to_plain_text(node)
  BottomUpReducer.new(node).reduce do |n, child_values|
    plain_text_for_node(n, child_values)
  end.then(&method(:remove_trailing_newlines))
end

def plain_text_for_block(node, child_values)
  "#{remove_trailing_newlines(plain_text_for_child_values(child_values))}\n\n"
end

def plain_text_for_blockquote_node(node, child_values)
  text = plain_text_for_block(node, child_values)
  return "“”" if text.blank?
  text = text.dup
  text.insert(text.rindex(/\S/) + 1, "”")
  text.insert(text.index(/\S/), "“")
  text
end

def plain_text_for_br_node(node, _child_values)
  "\n"
end

def plain_text_for_child_values(child_values)
  child_values.join
end

def plain_text_for_div_node(node, child_values)
  "#{remove_trailing_newlines(plain_text_for_child_values(child_values))}\n"
end

def plain_text_for_figcaption_node(node, child_values)
  "[#{remove_trailing_newlines(plain_text_for_child_values(child_values))}]"
end

def plain_text_for_li_node(node, child_values)
  bullet = bullet_for_li_node(node)
  text = remove_trailing_newlines(plain_text_for_child_values(child_values))
  indentation = indentation_for_li_node(node)
  "#{indentation}#{bullet} #{text}\n"
end

def plain_text_for_list(node, child_values)
  "#{break_if_nested_list(node, plain_text_for_block(node, child_values))}"
end

def plain_text_for_node(node, child_values)
  if respond_to?(plain_text_method_for_node(node), true)
    send(plain_text_method_for_node(node), node, child_values)
  else
    plain_text_for_child_values(child_values)
  end
end

def plain_text_for_text_node(node, _child_values)
  remove_trailing_newlines(node.text)
end

def plain_text_for_unsupported_node(node, _child_values)
  ""
end

def plain_text_method_for_node(node)
  :"plain_text_for_#{node.name}_node"
end

def remove_trailing_newlines(text)
  text.chomp("")
end