#require 'fiona7/released_obj'
#require 'fiona7/edited_obj'

require 'digest/sha1'

module Fiona7
  class VersionHelper
    attr_reader :workspace_id, :revision_id, :content_state_id, :base_revision_id, :base_content_state_id
    def initialize(workspace_id)
      self.workspace_id = workspace_id.to_sym

      if self.workspace_id == :published
        self.compute_for_published
      else
        self.compute_for_rtc
      end
    end

    protected
    attr_writer :workspace_id, :revision_id, :content_state_id, :base_revision_id, :base_content_state_id

    def compute_for_published
      # NOTE: with this implementation
      #
      #   released content changed => revision change
      #
      # but not neccessarily
      #
      #   revision change => released content changed
      #
      query         = Fiona7::WriteObj.select('max(last_changed), count(*)').where('is_released = 1 AND is_edited = 0').to_sql
      last_changed, obj_count = *Fiona7::WriteObj.connection.execute(query).first

      # tag + padding + obj_count (hex) + last changed
      revision_id = "f" + ('0' * 17) + ("%08x" % obj_count.to_i) + last_changed.to_s

      @revision_id =
        @content_state_id =
        @base_revision_id =
        @base_content_state_id = revision_id
    end

    def compute_for_rtc
      first_query = Fiona7::WriteObj.select('1, count(*), max(last_changed), NULL').to_sql
      second_query= Fiona7::WriteObj.select("obj_id, is_released, last_changed, attr_values").order("last_changed DESC").limit(23).to_sql
      third_query = Fiona7::WriteObj.select('1, count(*), max(last_changed), NULL').where('is_released = 1 AND is_edited = 0').to_sql
      union_query = "SELECT * FROM ( #{first_query} ) QUERY1 UNION ALL SELECT * FROM ( #{second_query} ) QUERY2 UNION ALL SELECT * FROM ( #{third_query} ) QUERY3"

      # only one query executed
      results                   = Fiona7::WriteObj.connection.execute(union_query).to_a
      _, obj_count, last_changed= *results.shift
      _, pobj_count, plast_changed= *results.pop
      changed_contents          = results

      content_digest            = Digest::SHA1.hexdigest("#{changed_contents}")[0,17]

      # tag + content digest + obj_count (hex) + last changed
      rtc_version_id            = "b" + content_digest + ("%08x" % obj_count.to_i) + last_changed.to_s
      # tag + padding + obj_count (hex) + last changed
      published_version_id      = "f" + ('0' * 17) + ("%08x" % pobj_count.to_i) + plast_changed.to_s

      @revision_id = 
        @content_state_id = rtc_version_id

      @base_revision_id =
        @base_content_state_id = published_version_id
    end

  end
end