class RuboCop::Cop::Style::ElseAlignment

def base_for_method_definition(node)
  parent = node.parent
  if parent && parent.type == :send
    parent.loc.selector # For example "private def ..."
  else
    node.loc.keyword
  end
end

def base_range(node, base)
  if base
    base.loc.expression
  else
    base = node
    until %w(if unless).include?(base.loc.keyword.source)
      base = base.parent
    end
    base.loc.keyword
  end
end

def check_alignment(base_range, else_range)
  return unless begins_its_line?(else_range)
  @column_delta = base_range.column - else_range.column
  return if @column_delta == 0
  add_offense(else_range, else_range,
              format(MSG, else_range.source, base_range.source[/^\S*/]))
end

def check_assignment(node, rhs)
  # If there are method calls chained to the right hand side of the
  # assignment, we let rhs be the receiver of those method calls before
  # we check its indentation.
  rhs = first_part_of_call_chain(rhs)
  return unless rhs
  end_config = config.for_cop('Lint/EndAlignment')
  style = end_config['Enabled'] ? end_config['AlignWith'] : 'keyword'
  base = variable_alignment?(node.loc, rhs, style.to_sym) ? node : rhs
  return if rhs.type != :if
  on_if(rhs, base)
  ignore_node(rhs)
end

def on_case(node)
  _cond, *whens, _else = *node
  return unless node.loc.else
  check_alignment(whens.last.loc.keyword, node.loc.else)
end

def on_if(node, base = nil)
  return if ignored_node?(node)
  return unless node.loc.respond_to?(:else)
  return if node.loc.else.nil?
  else_range = node.loc.else
  return unless begins_its_line?(else_range)
  check_alignment(base_range(node, base), else_range)
  return if else_range.source != 'elsif'
  # If the `else` part is actually an `elsif`, we check the `elsif`
  # node in case it contains an `else` within, because that `else`
  # should have the same alignment (base).
  _condition, _if_body, else_body = *node
  on_if(else_body, base)
  # The `elsif` node will get an `on_if` call from the framework later,
  # but we're done here, so we set it to ignored.
  ignore_node(else_body)
end

def on_rescue(node)
  return unless node.loc.else
  parent = node.parent
  parent = parent.parent if parent.type == :ensure
  base = case parent.type
         when :def, :defs then base_for_method_definition(parent)
         when :kwbegin then parent.loc.begin
         else node.loc.keyword
         end
  check_alignment(base, node.loc.else)
end