class RuboCop::Cop::Lint::HeredocMethodCallPosition

def all_on_same_line?(nodes)
  return true if nodes.empty?
  nodes.first.first_line == nodes.last.last_line
end

def autocorrect(corrector, node, heredoc)
  call_range = call_range_to_safely_reposition(node, heredoc)
  return if call_range.nil?
  call_source = call_range.source.strip
  corrector.remove(call_range)
  corrector.insert_after(heredoc_begin_line_range(node), call_source)
end

def call_after_heredoc_range(heredoc)
  pos = heredoc_end_pos(heredoc)
  range_between(pos + 1, pos + 2)
end

def call_end_pos(node)
  node.source_range.end_pos
end

def call_line_range(node)
  pos = node.source_range.end_pos
  range_by_whole_lines(range_between(pos, pos))
end

def call_range_to_safely_reposition(node, heredoc)
  return nil if calls_on_multiple_lines?(node, heredoc)
  heredoc_end_pos = heredoc_end_pos(heredoc)
  call_end_pos = call_end_pos(node)
  call_range = range_between(heredoc_end_pos, call_end_pos)
  call_line_range = call_line_range(node)
  call_source = call_range.source.strip
  call_line_source = call_line_range.source.strip
  return call_range if call_source == call_line_source
  if trailing_comma?(call_source, call_line_source)
    # If there's some on the last line other than the call, e.g.
    # a trailing comma, then we leave the "\n" following the
    # heredoc_end in place.
    return range_between(heredoc_end_pos, call_end_pos + 1)
  end
  nil
end

def calls_on_multiple_lines?(node, _heredoc)
  last_line = node.last_line
  while send_node?(node)
    return true unless last_line == node.last_line
    return true unless all_on_same_line?(node.arguments)
    node = node.receiver
  end
  false
end

def correctly_positioned?(node, heredoc)
  heredoc_end_pos(heredoc) > call_end_pos(node)
end

def heredoc_begin_line_range(heredoc)
  pos = heredoc.source_range.begin_pos
  range_by_whole_lines(range_between(pos, pos))
end

def heredoc_end_pos(heredoc)
  heredoc.location.heredoc_end.end_pos
end

def heredoc_node?(node)
  node.respond_to?(:heredoc?) && node.heredoc?
end

def heredoc_node_descendent_receiver(node)
  while send_node?(node)
    return node.receiver if heredoc_node?(node.receiver)
    node = node.receiver
  end
end

def on_send(node)
  heredoc = heredoc_node_descendent_receiver(node)
  return unless heredoc
  return if correctly_positioned?(node, heredoc)
  add_offense(call_after_heredoc_range(heredoc)) do |corrector|
    autocorrect(corrector, node, heredoc)
  end
end

def send_node?(node)
  return false unless node
  node.call_type?
end

def trailing_comma?(call_source, call_line_source)
  "#{call_source}," == call_line_source
end