class RuboCop::Cop::Style::IndentationWidth

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 = style == 'variable' ? node : rhs
  case rhs.type
  when :if            then on_if(rhs, base)
  when :while, :until then on_while(rhs, base)
  else                     return
  end
  ignore_node(rhs)
end

def check_if(node, body, else_clause, base_loc)
  return if ternary_op?(node)
  check_indentation(base_loc, body)
  return unless else_clause
  if elsif?(else_clause)
    _condition, inner_body, inner_else_clause = *else_clause
    check_if(else_clause, inner_body, inner_else_clause, base_loc)
  else
    check_indentation(node.loc.else, else_clause)
  end
end

def check_indentation(base_loc, body_node)
  return unless body_node
  # Don't check if expression is on same line as "then" keyword, etc.
  return if body_node.loc.line == base_loc.line
  return if starts_with_access_modifier?(body_node)
  # Don't check indentation if the line doesn't start with the body.
  # For example, lines like "else do_something".
  first_char_pos_on_line = body_node.loc.expression.source_line =~ /\S/
  return unless body_node.loc.column == first_char_pos_on_line
  indentation = body_node.loc.column - base_loc.column
  @column_delta = CORRECT_INDENTATION - indentation
  return if @column_delta == 0
  # This cop only auto-corrects the first statement in a def body, for
  # example.
  if body_node.type == :begin && !(body_node.loc.begin &&
                                   body_node.loc.begin.is?('('))
    body_node = body_node.children.first
  end
  expr = body_node.loc.expression
  begin_pos, ind = expr.begin_pos, expr.begin_pos - indentation
  pos = indentation >= 0 ? ind..begin_pos : begin_pos..ind
  r = Parser::Source::Range.new(expr.source_buffer, pos.begin, pos.end)
  add_offense(body_node, r,
              format("Use #{CORRECT_INDENTATION} (not %d) spaces " \
                     'for indentation.', indentation))
end

def on_block(node)
  _method, _args, body = *node
  # Check body against end/} indentation. Checking against variable
  # assignments, etc, would be more difficult. The end/} must be at the
  # beginning of its line.
  loc = node.loc
  check_indentation(loc.end, body) if begins_its_line?(loc.end)
end

def on_case(node)
  _condition, *branches = *node
  latest_when = nil
  branches.compact.each do |b|
    if b.type == :when
      # TODO: Revert to the original expresson once the fix in Rubinius
      #   is released.
      #
      # Originally this expression was:
      #
      #   *_conditions, body = *b
      #
      # However it fails on Rubinius 2.2.9 due to its bug:
      #
      #   RuntimeError:
      #     can't modify frozen instance of Array
      #   # kernel/common/array.rb:988:in `pop'
      #   # ./lib/rubocop/cop/style/indentation_width.rb:99:in `on_case'
      #
      # It seems to be fixed on the current master (0a92c3c).
      body = b.children.last
      # Check "when" body against "when" keyword indentation.
      check_indentation(b.loc.keyword, body)
      latest_when = b
    else
      # Since it's not easy to get the position of the "else" keyword,
      # we check "else" body against latest "when" keyword indentation.
      check_indentation(latest_when.loc.keyword, b)
    end
  end
end

def on_class(node)
  _class_name, _base_class, *members = *node
  members.each { |m| check_indentation(node.loc.keyword, m) }
end

def on_ensure(node)
  _body, ensure_body = *node
  check_indentation(node.loc.keyword, ensure_body)
end

def on_for(node)
  _variable, _collection, body = *node
  check_indentation(node.loc.keyword, body)
end

def on_if(node, base = node)
  return if ignored_node?(node)
  return if ternary_op?(node)
  return if modifier_if?(node)
  case node.loc.keyword.source
  when 'if'     then _condition, body, else_clause = *node
  when 'unless' then _condition, else_clause, body = *node
  else               _condition, body = *node
  end
  check_if(node, body, else_clause, base.loc) if body
end

def on_kwbegin(node)
  # Check indentation against end keyword but only if it's first on its
  # line.
  return unless begins_its_line?(node.loc.end)
  check_indentation(node.loc.end, node.children.first)
end

def on_method(node, _method_name, _args, body)
  check_indentation(node.loc.keyword, body) unless ignored_node?(node)
end

def on_module(node)
  _module_name, *members = *node
  members.each { |m| check_indentation(node.loc.keyword, m) }
end

def on_rescue(node)
  _begin_node, *rescue_nodes, else_node = *node
  rescue_nodes.each do |rescue_node|
    _, _, body = *rescue_node
    check_indentation(rescue_node.loc.keyword, body)
  end
  check_indentation(node.loc.else, else_node)
end

def on_send(node)
  super
  receiver, method_name, *args = *node
  return unless visibility_and_def_on_same_line?(receiver, method_name,
                                                 args)
  _method_name, _args, body = *args.first
  check_indentation(node.loc.expression, body)
  ignore_node(args.first)
end

def on_while(node, base = node)
  _condition, body = *node
  return unless node.loc.keyword.begin_pos ==
    node.loc.expression.begin_pos
  check_indentation(base.loc, body)
end

def starts_with_access_modifier?(body_node)
  body_node.type == :begin && modifier_node?(body_node.children.first)
end