class Rock
  def self.turn_on(flag_name)
    enable(flag_name, true)
  end

  def self.turn_off(flag_name)
    enable(flag_name, false)
  end

  def self.on?(flag_name)
    result = sql <<-SQL
        SELECT enabled FROM feature_flags
        WHERE name = '#{flag_name}';
    SQL
    result&.first&.dig("enabled") || false
  end

  def self.off?(flag_name)
    !on?(flag_name)
  end

  def self.delete(flag_name)
    sql <<-SQL
        DELETE FROM feature_flags
        WHERE name = '#{flag_name}';
    SQL
  end

  def self.delete_all_disabled
    sql <<-SQL
        DELETE FROM feature_flags
        WHERE enabled = false;
    SQL
  end

  private

  def self.enable(flag_name, enabled)
    sql <<-SQL
        INSERT INTO feature_flags (name, enabled, created_at, updated_at)
        VALUES ('#{flag_name}', #{enabled}, now(), now())
        ON CONFLICT (name) DO UPDATE SET enabled = #{enabled};
    SQL
  end

  def self.sql(query_string)
    ActiveRecord::Base.connection.execute(query_string)
  end
end