class RuboCop::Cop::Lint::UnneededDisable

def add_offense_for_entire_comment(comment, cops)
  location = comment.loc.expression
  cop_list = cops.sort.map { |c| describe(c) }
  add_offense([[location], location], location,
              "Unnecessary disabling of #{cop_list.join(', ')}.")
end

def add_offense_for_some_cops(comment, cops)
  cop_ranges = cops.map { |c| [c, cop_range(comment, c)] }
  cop_ranges.sort_by! { |_, r| r.begin_pos }
  ranges = cop_ranges.map { |_, r| r }
  cop_ranges.each do |cop, range|
    add_offense([ranges, range], range,
                "Unnecessary disabling of #{describe(cop)}.")
  end
end

def add_offenses(unneeded_cops)
  unneeded_cops.each do |comment, cops|
    if all_disabled?(comment) ||
       directive_count(comment) == cops.size
      add_offense_for_entire_comment(comment, cops)
    else
      add_offense_for_some_cops(comment, cops)
    end
  end
end

def all_cop_names
  @all_cop_names ||= Cop.all.map(&:cop_name)
end

def all_disabled?(comment)
  comment.text =~ /rubocop:disable\s+all\b/
end

def autocorrect(args)
  lambda do |corrector|
    ranges, range = *args # Ranges are sorted by position.
    range = if range.source.start_with?('#')
              comment_range_with_surrounding_space(range)
            else
              directive_range_in_list(range, ranges)
            end
    corrector.remove(range)
  end
end

def check(offenses, cop_disabled_line_ranges, comments)
  unneeded_cops = Hash.new { |h, k| h[k] = Set.new }
  each_unneeded_disable(cop_disabled_line_ranges,
                        offenses, comments) do |comment, unneeded_cop|
    unneeded_cops[comment].add(unneeded_cop)
  end
  add_offenses(unneeded_cops)
end

def collect_variable_like_names(scope)
  all_cop_names.each { |name| scope << name }
end

def comment_range_with_surrounding_space(range)
  # Eat the entire comment, the preceding space, and the preceding
  # newline if there is one.
  original_begin = range.begin_pos
  range = range_with_surrounding_space(range, :left, true)
  range_with_surrounding_space(range, :right,
                               # Special for a comment that
                               # begins the file: remove
                               # the newline at the end.
                               original_begin.zero?)
end

def cop_range(comment, cop)
  matching_range(comment.loc.expression, cop) ||
    matching_range(comment.loc.expression, cop.split('/').last) ||
    raise("Couldn't find #{cop} in comment: #{comment.text}")
end

def describe(cop)
  if cop == 'all'
    'all cops'
  elsif all_cop_names.include?(cop)
    "`#{cop}`"
  else
    similar = find_similar_name(cop, [])
    if similar
      "`#{cop}` (did you mean `#{similar}`?)"
    else
      "`#{cop}` (unknown cop)"
    end
  end
end

def directive_count(comment)
  match = comment.text.match(CommentConfig::COMMENT_DIRECTIVE_REGEXP)
  _, cops_string = match.captures
  cops_string.split(/,\s*/).size
end

def directive_range_in_list(range, ranges)
  # Is there any cop between this one and the end of the line, which
  # is NOT being removed?
  if ends_its_line?(ranges.last) && trailing_range?(ranges, range)
    # Eat the comma on the left.
    range = range_with_surrounding_space(range, :left)
    range = range_with_surrounding_comma(range, :left)
  end
  range = range_with_surrounding_comma(range, :right)
  # Eat following spaces up to EOL, but not the newline itself.
  range_with_surrounding_space(range, :right, false)
end

def each_already_disabled(line_ranges, comments)
  line_ranges.each_cons(2) do |previous_range, range|
    next if previous_range.end != range.begin
    # If a cop is disabled in a range that begins on the same line as
    # the end of the previous range, it means that the cop was
    # already disabled by an earlier comment. So it's unneeded
    # whether there are offenses or not.
    yield comments.find { |c| c.loc.line == range.begin }
  end
end

def each_unneeded_disable(cop_disabled_line_ranges, offenses, comments)
  disabled_ranges = cop_disabled_line_ranges[COP_NAME] || [0..0]
  cop_disabled_line_ranges.each do |cop, line_ranges|
    each_already_disabled(line_ranges, comments) do |comment|
      yield comment, cop
    end
    line_ranges.each do |line_range|
      comment = comments.find { |c| c.loc.line == line_range.begin }
      unless all_disabled?(comment)
        next if ignore_offense?(disabled_ranges, line_range)
      end
      unneeded_cop = find_unneeded(comment, offenses, cop, line_range)
      yield comment, unneeded_cop if unneeded_cop
    end
  end
end

def find_unneeded(comment, offenses, cop, line_range)
  if all_disabled?(comment)
    'all' if offenses.none? { |o| line_range.cover?(o.line) }
  else
    cop_offenses = offenses.select { |o| o.cop_name == cop }
    cop if cop_offenses.none? { |o| line_range.cover?(o.line) }
  end
end

def ignore_offense?(disabled_ranges, line_range)
  disabled_ranges.any? do |range|
    range.cover?(line_range.min) && range.cover?(line_range.max)
  end
end

def matching_range(haystack, needle)
  offset = (haystack.source =~ Regexp.new(Regexp.escape(needle)))
  return unless offset
  offset += haystack.begin_pos
  Parser::Source::Range.new(haystack.source_buffer, offset,
                            offset + needle.size)
end

def trailing_range?(ranges, range)
  ranges
    .drop_while { |r| !r.equal?(range) }
    .each_cons(2)
    .map { |r1, r2| r1.end.join(r2.begin).source }
    .all? { |intervening| intervening =~ /\A\s*,\s*\Z/ }
end