module RuboCop::Cop::MultilineExpressionIndentation

def argument_in_method_call(node)
  node.each_ancestor(:send, :block).find do |a|
    # If the node is inside a block, it makes no difference if that block
    # is an argument in a method call. It doesn't count.
    break false if a.block_type?
    _, method_name, *args = *a
    next if assignment_call?(method_name)
    args.any? { |arg| within_node?(node, arg) }
  end
end

def assignment_call?(method_name)
  method_name == :[]= || method_name.to_s =~ /^\w.*=$/
end

def assignment_rhs(node)
  case node.type
  when :casgn   then _scope, _lhs, rhs = *node
  when :op_asgn then _lhs, _op, rhs = *node
  when :send    then _receiver, _method_name, *_args, rhs = *node
  else               _lhs, rhs = *node
  end
  rhs
end

def check(range, node, lhs, rhs)
  if range
    incorrect_style_detected(range, node, lhs, rhs)
  else
    correct_style_detected
  end
end

def correct_indentation(node)
  if kw_node_with_special_indentation(node)
    # This cop could have its own IndentationWidth configuration
    configured_indentation_width +
      @config.for_cop('Style/IndentationWidth')['Width']
  else
    configured_indentation_width
  end
end

def grouped_expression?(node)
  node.begin_type? && node.loc.respond_to?(:begin) && node.loc.begin
end

def incorrect_style_detected(range, node, lhs, rhs)
  add_offense(range, range, message(node, lhs, rhs)) do
    if supported_styles.size > 2 ||
       offending_range(node, lhs, rhs, alternative_style)
      unrecognized_style_detected
    else
      opposite_style_detected
    end
  end
end

def indentation(node)
  node.source_range.source_line =~ /\S/
end

def inside_arg_list_parentheses?(node, ancestor)
  a = ancestor.loc
  return false unless ancestor.send_type? && a.begin &&
                      a.begin.is?('(')
  n = node.source_range
  n.begin_pos > a.begin.begin_pos && n.end_pos < a.end.end_pos
end

def kw_node_with_special_indentation(node)
  node.each_ancestor.find do |a|
    next unless a.loc.respond_to?(:keyword)
    case a.type
    when :for                  then _, expression, = *a
    when :return               then expression, = *a
    when *Util::MODIFIER_NODES then expression, = *a
    end
    within_node?(node, expression) if expression
  end
end

def left_hand_side(lhs)
  lhs = lhs.parent while lhs.parent && lhs.parent.send_type?
  lhs
end

def not_for_this_cop?(node)
  node.each_ancestor.any? do |ancestor|
    grouped_expression?(ancestor) ||
      inside_arg_list_parentheses?(node, ancestor)
  end
end

def on_send(node)
  return unless relevant_node?(node)
  receiver, method_name, *_args = *node
  return unless receiver
  return if method_name == :[] # Don't check parameters inside [].
  lhs = left_hand_side(receiver)
  rhs = right_hand_side(node)
  range = offending_range(node, lhs, rhs, style)
  check(range, node, lhs, rhs)
end

def operation_description(node, rhs)
  ancestor = kw_node_with_special_indentation(node)
  if ancestor
    kw = ancestor.loc.keyword.source
    kind = kw == 'for' ? 'collection' : 'condition'
    article = kw =~ /^[iu]/ ? 'an' : 'a'
    "a #{kind} in #{article} `#{kw}` statement"
  else
    'an expression' +
      (part_of_assignment_rhs(node, rhs) ? ' in an assignment' : '')
  end
end

def part_of_assignment_rhs(node, candidate)
  node.each_ancestor.find do |a|
    case a.type
    when :if, :while, :until, :for, :return, :array, :kwbegin
      break # other kinds of alignment
    when :block
      break if part_of_block_body?(candidate, a)
    when :send
      valid_method_rhs_candidate?(candidate, a)
    when *Util::ASGN_NODES
      valid_rhs_candidate?(candidate, assignment_rhs(a))
    end
  end
end

def part_of_block_body?(candidate, node)
  _method, _args, body = *node
  body && within_node?(candidate, body)
end

def regular_method_right_hand_side(send_node)
  dot = send_node.loc.dot
  selector = send_node.loc.selector
  if dot && selector && dot.line == selector.line
    dot.join(selector)
  elsif selector
    selector
  elsif dot.line == send_node.loc.begin.line
    # lambda.(args)
    dot.join(send_node.loc.begin)
  end
end

def right_hand_side(send_node)
  _, method_name, *args = *send_node
  if operator?(method_name) && args.any?
    args.first.source_range # not used for method calls
  else
    regular_method_right_hand_side(send_node)
  end
end

def valid_method_rhs_candidate?(candidate, node)
  _receiver, method_name, *args = *node
  assignment_call?(method_name) &&
    valid_rhs_candidate?(candidate, args.last)
end

def valid_rhs_candidate?(candidate, node)
  !candidate || within_node?(candidate, node)
end