desc 'clean unused IVR tables'

clean_unused_ivr.rake

namespace :db do
  desc 'clean unused IVR tables'
  task :clean_unused_ivr_tables, :suffix1, :suffix2, :needs => :environment do |t, args|

    def current_version
      ivr_config_file  = File.dirname(__FILE__) + "/../../config/ivr_version.yml"
      raise 'Missing ivr_version.yml' unless File.exists?(ivr_config_file)

      ivr_version = YAML.load_file(File.expand_path(ivr_config_file)).to_s
      raise 'Empty or broken ivr_version.yml' unless ivr_version =~ /\A\d+\Z/

      ivr_version
    end

    # default value if no args passed
    args.with_defaults(:suffix1 => current_version)

    # 1234|5678 if 2 args, else 1234
    ivr_versions = [args[:suffix1], args[:suffix2]].compact.join('|')

    db = ActiveRecord::Base.connection

    IVR_TABLES = %w(
      ivr_digraph_versions
      ivr_entry_node_configurations
      ivr_error_prompt_segments
      ivr_error_prompts
      ivr_menu_options
      ivr_menu_prompt_segments
      ivr_node_rules
      ivr_nodes
      ivr_opening_prompt_segments
      ivr_prompt_segments
    )
    regexp = %r(\A(#{IVR_TABLES.join '|'})_[0-9]+\Z)

    tables = db.select_values("SHOW TABLES LIKE 'ivr_%'").
      select{ |el| el =~ regexp }.
      reject{ |el| el =~ /(#{ivr_versions})\Z/ }

    tables.each do |table|
      cmd = "DROP TABLE #{table}"
      puts cmd
      db.execute cmd
    end

  end
end