# TestDiff module
module TestDiff
  # class used to build the coverage file
  class BuildCoverageDiff
    attr_reader :spec_folder, :pre_load, :sha1

    def initialize(spec_folder, pre_load, continue)
      @spec_folder = spec_folder
      @sha1 = File.read('test_diff_coverage/sha')
      @tests_to_run = []
      @storage = Storage.new
      @pre_load = pre_load
      @continue = continue
    end

    def run
      RunableTests.new(@tests_to_run, @spec_folder).add_changed_files
      remove_tests_that_do_not_exist
      remove_tests_in_wrong_folder
      require 'coverage.so'
      Coverage.start
      require_pre_load
      run_batch
    end

    private

    def require_pre_load
      return unless pre_load
      puts "pre_loading #{pre_load}"
      require File.expand_path(pre_load)
    end

    def run_batch
      puts "Running #{@tests_to_run.size} tests"
      start
      puts 'Test done, compacting db'
      @storage.compact if @storage.respond_to?(:compact)
    end

    def start
      until @tests_to_run.empty?
        pid = start_process_fork(@tests_to_run.pop.filename)
        pid, status =  Process.waitpid2(pid)
        fail 'Test Failed' unless status.success?
      end
      Coverage.result # disable coverage
    end

    def start_process_fork(main_spec_file)
      Process.fork do
        puts "running #{main_spec_file}"
        ActiveRecord::Base.connection.reconnect! if defined?(ActiveRecord::Base)
        Time.zone_default = (Time.zone = 'UTC') if Time.respond_to?(:zone_default) && Time.zone_default.nil?
        run_test(main_spec_file)
      end
    end

    def run_test(main_spec_file)
      s = Time.now
      result = run_tests(main_spec_file)
      if result
        save_coverage_data(main_spec_file, Time.now - s)
      else
        Coverage.result # disable coverage
        exit!(false) unless @continue
      end
    end

    def run_tests(main_spec_file)
      if defined?(::RSpec::Core::Runner)
        ::RSpec::Core::Runner.run([main_spec_file], $stderr, $stdout) == 0
      else
        options ||= begin
          parser = ::Spec::Runner::OptionParser.new($stderr, $stdout)
          parser.order!(['-b', main_spec_file])
          parser.options
        end
        Spec::Runner.use options
        options.run_examples
      end
    end

    def save_coverage_data(main_spec_file, execution_time)
      data = { '__execution_time__' => execution_time }
      Coverage.result.each do |file_name, stats|
        relative_file_name = file_name.gsub("#{FileUtils.pwd}/", '')
        if file_name.include?(FileUtils.pwd)
          data[relative_file_name] = stats.join(',')
        end
      end
      YAML::ENGINE.yamler = 'psych'
      @storage.set(main_spec_file, data)
      @storage.flush if @storage.respond_to?(:flush)
    end

    def remove_tests_that_do_not_exist
      @tests_to_run.delete_if do |s|
        !File.exist?("#{Config.working_directory}/#{s.filename}")
      end
    end

    def remove_tests_in_wrong_folder
      @tests_to_run.delete_if do |s|
        !s.filename.start_with?("#{spec_folder}/")
      end
    end
  end
end