```ruby
require 'nicorepo/report'
require 'forwardable'

class Nicorepo
  class Reports
    extend Forwardable

    TOP_URL = 'http://www.nicovideo.jp/my/top'

    attr_reader :reports
    def_delegators :@reports, :size

    def initialize(parser)
      @parser = parser
      @reports = []
    end

    def fetch(request_num, limit_page)
      @reports = fetch_recursively(request_num, limit_page)
    end

    def fetch_and_select_with(filter, request_num, limit_page)
      @reports = fetch_recursively(request_num, limit_page, filter)
    end

    private

    def fetch_recursively(request_num, limit_page, filter = nil, url = TOP_URL)
      return [] unless limit_page > 0

      # fetch current page reports
      page = @parser.parse_page(url)
      reports = page[:reports_attrs].map { |attrs| Report.new(attrs) }
      reports.select!{ |report| report.kind =~ /#{filter}/ } if filter

      return reports[0, request_num] if reports.size >= request_num

      # recursively fetch next reports
      next_reports = fetch_recursively(request_num - reports.size, limit_page - 1, filter, page[:next_url])
      reports += next_reports unless next_reports.nil?
      reports
    end
  end

  class VideoReports < Reports
    def fetch(request_num, limit_page)
      fetch_and_select_with('video-upload', request_num, limit_page)
    end
  end

  class LiveReports < Reports
    def fetch(request_num, limit_page)
      fetch_and_select_with('live', request_num, limit_page)
    end
  end
end

```

Clarify differences of selecting kind filter
user
```ruby
require 'nicorepo/report'
require 'forwardable'

class Nicorepo
  class Reports
    extend Forwardable

    TOP_URL = 'http://www.nicovideo.jp/my/top'

    attr_reader :reports
    def_delegators :@reports, :size

    def initialize(parser)
      @parser = parser
      @reports = []
    end

    def fetch(request_num, limit_page)
      filter = selected_kind
      @reports = fetch_recursively(request_num, limit_page, filter)
    end

    private

    def selected_kind
      nil
    end

    def fetch_recursively(request_num, limit_page, filter = nil, url = TOP_URL)
      return [] unless limit_page > 0

      # fetch current page reports
      page = @parser.parse_page(url)
      reports = page[:reports_attrs].map { |attrs| Report.new(attrs) }
      reports.select!{ |report| report.kind =~ /#{filter}/ } if filter

      return reports[0, request_num] if reports.size >= request_num

      # recursively fetch next reports
      next_reports = fetch_recursively(request_num - reports.size, limit_page - 1, filter, page[:next_url])
      reports += next_reports unless next_reports.nil?
      reports
    end
  end

  class VideoReports < Reports
    private

    def selected_kind
      'video-upload'
    end
  end

  class LiveReports < Reports
    private

    def selected_kind
      'live'
    end
  end
end

```
assistant