module DbHelpers

  def self.pg?
    ENV.has_key? "PG"
  end

  def self.jruby?
    (defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby') || defined?(JRUBY_VERSION)
  end

  def db_setup(opts={})
    use_time = opts[:use_time]
    DB.drop_table(:room_versions) if DB.table_exists?(:room_versions)
    DB.drop_table(:rooms) if DB.table_exists?(:rooms)
    DB.create_table! :rooms do
      primary_key :id
      Boolean     :disabled, null: false, default: false
    end
    DB.create_table! :room_versions do
      primary_key :id
      foreign_key :master_id, :rooms
      String      :name
      Fixnum      :price
      Fixnum      :length
      Fixnum      :width
      send(use_time ? :Time : :Date, :created_at)
      send(use_time ? :Time : :Date, :expired_at)
      send(use_time ? :Time : :Date, :valid_from)
      send(use_time ? :Time : :Date, :valid_to)
    end
    @version_class = Class.new Sequel::Model do
      set_dataset :room_versions
      def validate
        super
        errors.add(:name, "is required") unless name
        errors.add(:price, "is required") unless price
      end
    end

    bitemporal_options = {version_class: @version_class}
    bitemporal_options[:audit_class] = opts[:audit_class] if opts[:audit_class]
    bitemporal_options[:audit_updated_by_method] = opts[:audit_updated_by_method] if opts[:audit_updated_by_method]
    bitemporal_options[:ranges] = opts[:ranges] if opts[:ranges]

    @master_class = Class.new Sequel::Model do
      set_dataset :rooms
      plugin :bitemporal, bitemporal_options
    end

    DB.drop_table(:my_name_versions) if DB.table_exists?(:my_name_versions)
    DB.drop_table(:my_names) if DB.table_exists?(:my_names)

    DB.create_table! :my_names do
      primary_key :id
    end
    DB.create_table! :my_name_versions do
      primary_key :id
      foreign_key :master_id, :my_names
      send(use_time ? :Time : :Date, :created_at)
      send(use_time ? :Time : :Date, :expired_at)
      send(use_time ? :Time : :Date, :valid_from)
      send(use_time ? :Time : :Date, :valid_to)
    end
  end

  def setup_composite_primary_key(with_foreign_key: true)
    DB.drop_table(:employee_versions) if DB.table_exists?(:employee_versions)
    DB.drop_table(:employees) if DB.table_exists?(:employees)

    DB.create_table! :employees do
      Integer :department_id
      Integer :team_id
      primary_key [:department_id, :team_id]
      String :name, null: false
    end

    DB.create_table! :employee_versions do
      if with_foreign_key
        Integer :department_id
        Integer :team_id

        foreign_key [:department_id, :team_id], :employees
      end

      primary_key :id
      String :position
      Date :created_at
      Date :expired_at
      Date :valid_from
      Date :valid_to
    end

    @version_class = Class.new Sequel::Model do
      set_dataset :employee_versions
    end

    bitemporal_options = {
      version_class: @version_class,
      key: [:department_id, :team_id]
    }

    @master_class = Class.new Sequel::Model do
      set_dataset :employees
      plugin :bitemporal, bitemporal_options
    end
  end

  def db_truncate
    if DbHelpers.pg?
      @version_class.truncate cascade: true
      @master_class.truncate cascade: true
    else
      @version_class.truncate
      @master_class.truncate
    end
  end
end