class ParallelTests::Test::Runner

def capture_output(out, silence)
  result = ""
  loop do
    begin
      read = out.readpartial(1000000) # read whatever chunk we can get
      if Encoding.default_internal
        read = read.force_encoding(Encoding.default_internal)
      end
      result << read
      unless silence
        $stdout.print read
        $stdout.flush
      end
    end
  end rescue EOFError
  result
end

def determine_executable
  "ruby"
end

def executable
  ENV['PARALLEL_TESTS_EXECUTABLE'] || determine_executable
end

def execute_command(cmd, process_number, num_processes, options)
  env = (options[:env] || {}).merge(
    "TEST_ENV_NUMBER" => test_env_number(process_number),
    "PARALLEL_TEST_GROUPS" => num_processes
  )
  cmd = "nice #{cmd}" if options[:nice]
  cmd = "#{cmd} 2>&1" if options[:combine_stderr]
  puts cmd if options[:verbose]
  execute_command_and_capture_output(env, cmd, options[:serialize_stdout])
end

def execute_command_and_capture_output(env, cmd, silence)
  # make processes descriptive / visible in ps -ef
  separator = (WINDOWS ? ' & ' : ';')
  exports = env.map do |k,v|
    if WINDOWS
      "(SET \"#{k}=#{v}\")"
    else
      "#{k}=#{v};export #{k}"
    end
  end.join(separator)
  cmd = "#{exports}#{separator}#{cmd}"
  output = open("|#{cmd}", "r") { |output| capture_output(output, silence) }
  exitstatus = $?.exitstatus
  {:stdout => output, :exit_status => exitstatus}
end

def files_in_folder(folder, options={})
  pattern = if options[:symlinks] == false # not nil or true
    "**/*"
  else
    # follow one symlink and direct children
    # http://stackoverflow.com/questions/357754/can-i-traverse-symlinked-directories-in-ruby-with-a-glob
    "**{,/*/**}/*"
  end
  Dir[File.join(folder, pattern)].uniq
end

def find_results(test_output)
  test_output.split("\n").map {|line|
    line.gsub!(/\e\[\d+m/,'')
    next unless line_is_result?(line)
    line
  }.compact
end

def find_tests(tests, options = {})
  (tests || []).map do |file_or_folder|
    if File.directory?(file_or_folder)
      files = files_in_folder(file_or_folder, options)
      files.grep(test_suffix).grep(options[:pattern]||//)
    else
      file_or_folder
    end
  end.flatten.uniq
end

def line_is_result?(line)
  line.gsub!(/[.F*]/,'')
  line =~ /\d+ failure/
end

def name
  NAME
end

def run_tests(test_files, process_number, num_processes, options)
  require_list = test_files.map { |file| file.sub(" ", "\\ ") }.join(" ")
  cmd = "#{executable} -Itest -e '%w[#{require_list}].each { |f| require %{./\#{f}} }' -- #{options[:test_options]}"
  execute_command(cmd, process_number, num_processes, options)
end

def runtime_log
  'tmp/parallel_runtime_test.log'
end

def runtimes(options)
  log = options[:runtime_log] || runtime_log
  File.read(log).split("\n")
end

def sort_by_filesize(tests)
  tests.sort!
  tests.map! { |test| [test, File.stat(test).size] }
end

def sort_by_runtime(tests, runtimes, options={})
  allowed_missing = options[:allowed_missing] || 1.0
  allowed_missing = tests.size * allowed_missing
  times = {}
  runtimes.each do |line|
    test, time = line.split(":", 2)
    next unless test and time
    times[test] = time.to_f
  end
  tests.sort!
  tests.map! do |test|
    allowed_missing -= 1 unless time = times[test]
    raise "Too little runtime info" if allowed_missing < 0
    [test, time || 1]
  end
end

def sum_up_results(results)
  results = results.join(' ').gsub(/s\b/,'') # combine and singularize results
  counts = results.scan(/(\d+) (\w+)/)
  counts.inject(Hash.new(0)) do |sum, (number, word)|
    sum[word] += number.to_i
    sum
  end
end

def summarize_results(results)
  sums = sum_up_results(results)
  sums.sort.map{|word, number|  "#{number} #{word}#{'s' if number != 1}" }.join(', ')
end

def test_env_number(process_number)
  process_number == 0 ? '' : process_number + 1
end

def test_file_name
  "test"
end

def test_suffix
  /_(test|spec).rb$/
end

def tests_in_groups(tests, num_groups, options={})
  tests = find_tests(tests, options)
  case options[:group_by]
  when :found
    tests.map! { |t| [t, 1] }
  when :filesize
    sort_by_filesize(tests)
  when :runtime
    sort_by_runtime(tests, runtimes(options), allowed_missing: 0.5)
  when nil
    # use recorded test runtime if we got enough data
    runtimes = runtimes(options) rescue []
    if runtimes.size * 1.5 > tests.size
      puts "Using recorded test runtime"
      sort_by_runtime(tests, runtimes)
    else
      sort_by_filesize(tests)
    end
  else
    raise ArgumentError, "Unsupported option #{options[:group_by]}"
  end
  Grouper.in_even_groups_by_size(tests, num_groups, options)
end