class Root
  include Sys::Client
  
  attr_reader :root_path

  def initialize(root_path, clean = false)
    @root_path = root_path
    @clean = clean
    @status = nil
  end

  class Processes < Array
    def initialize
    end

    def launch
      pid = fork do
        yield
      end
      self << pid
    end

    def join
      self.each do |pid|
        Process.waitpid(pid, 0)
      end
    end
  end

  def update
    if @clean
      remove_unversioned
    end

    remove_deleted_externals

    externals_before = all_externals

    svn("up --ignore-externals #{root_path}")
    # for some reason (array - array) doesn't work right here
    # so i had to write my own subtract method
    removed_externals = externals_before.subtract(all_externals)
    removed_externals.each do |ext|
      say "Removed external #{ext}"
      FileUtils.rm_rf(ext.path)
    end

    @processes = Processes.new

    already_up_to_date = []
    all_externals.each do |external|
      if external.should_update?
        if File.exists?(external.path)
          update_external(external)
        else
          checkout_external(external)
        end
      else
        already_up_to_date << external
      end
    end

    unless already_up_to_date.empty?
      say("External#{'s' if already_up_to_date.size > 1} " +
        already_up_to_date.collect {|external| external.name}.join(", ") +
        " already up to date")
    end

    @processes.join
  end

  def update_external(external)
    @processes.launch do
      external.update
    end
  end

  def checkout_external(external)
    @processes.launch do
      external.checkout
    end
  end

  def remove_deleted_externals
    directories_containing_externals.each do |dir|
      deleted_something = false
      workspace_externals = External.externals_of(dir)
      Dir.chdir(root_path) do
        head_property = svn("propget -r HEAD svn:externals #{dir}", true)
        head_externals = External.externals_of(dir, head_property)
        deleted_externals = workspace_externals.select do |workspace_external|
          head_externals.select { |head_external| head_external.name == workspace_external.name }.empty?
        end
        unless deleted_externals.empty?
          deleted_externals.each do |external|
            # todo: check for local changes
            say("Deleting external #{external.path}")
            FileUtils.rm_rf(external.path)
          end
          # update the property first
          svn("up -N #{dir}")
          # then update all the deleted former externals
          svn("up " + deleted_externals.map{|external| "#{external.path}"}.join(" "))
        end
      end
      if deleted_something
        svn("up -N #{dir}")
        svn("up --ignore-externals #{dir}")
        puts "pausing"
        sleep(9999)
      end
    end
  end

  def remove_unversioned
    status.unversioned.each do |path|
      if File.directory?(path)
        say "Removing unversioned directory #{path}"
      else
        say "Removing unversioned file #{path}"
      end
      FileUtils.rm_rf(path)
    end
  end

  def status
    @status ||= Status.new(svn("st #{root_path}", true))
  end

  def all_externals
    exts = []
    directories_containing_externals.collect do |parent|
      exts += External.externals_of(parent)
    end
    exts
  end

  def directories_containing_externals
    status.externals.collect do |path|
      if (path !~ /\//)
        root_path
      else
        path.gsub(/\/[^\/]*$/, '')
      end
    end.uniq
  end

end