# Copyright (c) 2016-2022 Yegor Bugayenko
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the 'Software'), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

#
# XML cached in a temporary file.
#
class CachedStorage
  def initialize(origin, file)
    @origin = origin
    @file = file
  end

  def load
    if File.exist?(@file)
      xml = Nokogiri::XML(File.read(@file))
    else
      xml = @origin.load
      write(xml)
    end
    xml
  end

  def save(xml)
    File.delete(@file) if File.exist?(@file)
    @origin.save(xml)
    write(xml.to_s)
  end

  private

  def write(xml)
    FileUtils.mkdir_p(File.dirname(@file))
    File.write(@file, xml)
  end
end
