require 'singleton'
require 'tmpdir'
require 'yaml'

module RaPT
  class TestObserver
    include Singleton
  
    class Data
      attr_accessor :tests, :errors, :failures
      def initialize(t, e, f)
        @tests, @errors, @failures = t, e, f
      end
      def total_failures
        errors + failures
      end
    end
  
    PLUGIN_RESULTS_FILENAME = 'plugin_test_results.yml'
  
    # Restores the test data from it's saved location
    def self.load_data
      YAML.load(File.open(File.join(Dir.tmpdir, PLUGIN_RESULTS_FILENAME)))
    end
    
    attr_accessor :result

    def attach_mediator(mediator)
      # any time something changes in the test results (i.e. an assertion is encountered,
      # an error detected, or an assertion fails), we'll know about it.
      mediator.add_listener(Test::Unit::TestResult::CHANGED, &method(:set_result))
      
      # When the suite of tests is finished, save our test results away.
      mediator.add_listener(Test::Unit::UI::TestRunnerMediator::FINISHED, &method(:save))
    end
  
    # Saves test results into a temporary file for later retrieval
    def save(*args)
      raise "Empty results!!" if @result.nil?
      data = Data.new(@result.run_count, @result.error_count, @result.failure_count)
      File.open(File.join(Dir.tmpdir, PLUGIN_RESULTS_FILENAME), 'w') do |f|
        f.puts data.to_yaml
      end
    end
    
    private
  
    def set_result(r)
      @result = r # the result set that is passed through is the same each time.
    end
  end  
end