class UserAgent

def self.parse(string)
  agents = []
  while m = string.match(MATCHER)
    agents << new(m[1], m[2], m[4])
    string = string.sub(m[0], '').strip
  end
  Browsers.extend(agents)
  agents
end

def <=>(other)
  if @product == other.product
    if @version && other.version
      @version <=> other.version
    else
      0
    end
  else
    false
  end
end

def eql?(other)
  @product == other.product &&
    @version == other.version &&
    @comment == other.comment
end

def initialize(product, version = nil, comment = nil)
  if product
    @product = product
  else
    raise ArgumentError, "expected a value for product"
  end
  if version && !version.empty?
    @version = version
  else
    @version = nil
  end
  if comment.respond_to?(:split)
    @comment = comment.split("; ")
  else
    @comment = comment
  end
end

def to_s
  to_str
end

def to_str
  if @product && @version && @comment
    "#{@product}/#{@version} (#{@comment.join("; ")})"
  elsif @product && @version
    "#{@product}/#{@version}"
  elsif @product && @comment
    "#{@product} (#{@comment.join("; ")})"
  else
    @product
  end
end