module ActiveRecord

  class Migration


    def self.rename_table_if_needed(old_name, new_name)
      rename_table(old_name, new_name)
    rescue => ex
      puts "rename_table(#{old_name},#{new_name}) failed #{ex.message}"
    end

    def self.reset_sequence(model)
      if Biorails::Check.oracle?
        num = model.maximum(:id)+1
        name = "#{model.table_name}_seq"
        current_num = model.connection.select_one("select #{name}.nextval from dual")["nextval"].to_i
        diff = (num-current_num)
        if diff > 0
          puts "Update #{name} from #{current_num} to greater than #{num}"
          execute "alter sequence #{name} increment by #{diff} nocache"
          execute "select #{name}.nextval from dual"
          execute "alter sequence #{name} increment by 1 cache 20"
          execute "select #{name}.nextval from dual"
        end
      end
    rescue Exception => ex
      puts "Failed to update sequence on #{model} #{ex.message}"
    end

    def self.add_column_if_missing(table_name, column_name, type, options = {})
      unless table_exists?(table_name.to_s) && columns(table_name.to_s).any? { |i| i.name == column_name.to_s }
        add_column table_name, column_name, type, options
      end
    rescue => ex
      puts ex.message
    end

    def self.add_index_unless_exists(table_name, columns, options = {})
      add_index(table_name, columns, options)
    rescue => ex
      puts "skipped index #{ex.message}"
    end

    def self.run_sql(sql)
      execute sql
    rescue => ex
      puts sql
      puts "Error: #{ex.message}"
    end

    def self.remove_column_if_found(table_name, column_name, type=nil, options = {})
      if table_exists?(table_name.to_s) && columns(table_name.to_s).any? { |i| i.name == column_name.to_s }
        remove_column table_name, column_name
      end
    rescue => ex
      puts ex.message
    end

    def self.rename_column_if_found(table_name, old_name, new_name)
      if table_exists?(table_name.to_s) && columns(table_name.to_s).any? { |i| i.name == old_name.to_s }
        rename_column table_name, old_name, new_name
      end
    rescue Exception => ex
      puts ex.message
    end

    def self.rename_table_if_exists(old_name,new_name)
      if  table_exists?(old_name.to_s)
          rename_table(old_name,new_name)
      end
    end

    def self.create_table_if_missing(table_name, options = {}, &body)
      unless table_exists?(table_name.to_s)
        add_column table_name, options, &body
      end
    rescue => ex
      puts ex.message
    end

    def self.drop_table_if_exists(table_name, options = {})
      if table_exists?(table_name.to_s)
        drop_table table_name, options
      end
    rescue => ex
      puts ex.message
    end


  end

end