class HTTPAuth::Digest::Utils

# File lib/httpauth/digest.rb, line 194
def calculate_digest(h, s, variant)
  fail(ArgumentError, "Variant should be either :request or :response, not #{variant}") unless [:request, :response].include?(variant)
  # Compatability with RFC 2069
  if h[:qop].nil?
    digest_kd digest_a1(h, s), digest_concat(
      h[:nonce],
      send("#{variant}_digest_a2".intern, h)
    )
  else
    digest_kd digest_a1(h, s), digest_concat(
      h[:nonce],
      Conversions.int_to_hex(h[:nc]),
      h[:cnonce],
      h[:qop],
      send("#{variant}_digest_a2".intern, h)
    )
  end
end

# File lib/httpauth/digest.rb, line 227
def create_nonce(salt)
  now = Time.now
  time = now.strftime('%Y-%m-%d %H:%M:%S').to_s + ':' + now.usec.to_s
  Base64.encode64(
  digest_concat(
      time,
      digest_h(digest_concat(time, salt))
    )
  ).gsub("\n", '')[0..-3]
end

# File lib/httpauth/digest.rb, line 239
def create_opaque
  s = []
  16.times { s << rand(127).chr }
  digest_h s.join
end

# File lib/httpauth/digest.rb, line 89
def decode_directives(directives, variant)
  fail(HTTPAuth::UnwellformedHeader, "Can't decode directives which are nil") if directives.nil?
  decode = {:domain => :space_quoted_string_to_list, :algorithm => false, :stale => :str_to_bool, :nc => :hex_to_int}
  if [:credentials, :auth].include? variant
    decode.merge! :qop => false
  elsif variant == :challenge
    decode.merge! :qop => :comma_quoted_string_to_list
  else
    fail(ArgumentError, "#{variant} is not a valid value for `variant' use :auth, :credentials or :challenge")
  end

  start = 0
  unless variant == :auth
    # The first six characters are 'Digest '
    start = 6
    scheme = directives[0..6].strip
    fail(HTTPAuth::UnwellformedHeader, "Scheme should be Digest, server responded with `#{directives}'") unless scheme == 'Digest'
  end

  # The rest are the directives
  # TODO: split is ugly, I want a real parser (:
  directives[start..-1].split(',').inject({}) do |h, part|
    parts = part.split('=')
    name = parts[0].strip.intern
    value = parts[1..-1].join('=').strip

    # --- HACK
    # IE and Safari qoute qop values
    # IE also quotes algorithm values
    if variant != :challenge && [:qop, :algorithm].include?(name) && value =~ /^\"[^\"]+\"$/
      value = Conversions.unquote_string(value)
    end
    # --- END HACK

    if decode[name]
      h[name] = Conversions.send decode[name], value
    elsif decode[name].nil?
      h[name] = Conversions.unquote_string value
    else
      h[name] = value
    end
    h
  end
end

# File lib/httpauth/digest.rb, line 159
def digest_a1(h, s)
  # TODO: check for known algorithm values (look out for the IE algorithm quote bug)
  if h[:algorithm] == 'MD5-sess'
    digest_h digest_concat(
      h[:digest] || htdigest(h[:username], h[:realm], h[:password]),
      h[:nonce],
      h[:cnonce]
    )
  else
    h[:digest] || htdigest(h[:username], h[:realm], h[:password])
  end
end

# File lib/httpauth/digest.rb, line 138
def digest_concat(*args)
  args.join ':'
end

# File lib/httpauth/digest.rb, line 143
def digest_h(data)
  ::Digest::MD5.hexdigest data
end

# File lib/httpauth/digest.rb, line 148
def digest_kd(secret, data)
  digest_h digest_concat(secret, data)
end

# File lib/httpauth/digest.rb, line 56
def encode_directives(h, variant)
  encode = {:domain => :list_to_space_quoted_string, :algorithm => false, :stale => :bool_to_str, :nc => :int_to_hex}
  if [:credentials, :auth].include? variant
    encode.merge! :qop => false
  elsif variant == :challenge
    encode.merge! :qop => :list_to_comma_quoted_string
  else
    fail(ArgumentError, "#{variant} is not a valid value for `variant' use :auth, :credentials or :challenge")
  end
  (variant == :auth ? '' : 'Digest ') + h.collect do |directive, value|
    '' << directive.to_s << '=' << if encode[directive]
      begin
        Conversions.send encode[directive], value
      rescue NoMethodError, ArgumentError
        raise(ArgumentError, "Can't encode #{directive}(#{value.inspect}) with #{encode[directive]}")
      end
    elsif encode[directive].nil?
      begin
        Conversions.quote_string value
      rescue NoMethodError, ArgumentError
        raise(ArgumentError, "Can't encode #{directive}(#{value.inspect}) with quote_string")
      end
    else
      value
    end
  end.join(', ')
end

# File lib/httpauth/digest.rb, line 219
def filter_h_on(h, keys)
  h.inject({}) { |a, e| keys.include?(e[0]) ? a.merge(e[0] => e[1]) : a }
end

# File lib/httpauth/digest.rb, line 153
def htdigest(username, realm, password)
  digest_h digest_concat(username, realm, password)
end

# File lib/httpauth/digest.rb, line 173
def request_digest_a2(h)
  # TODO: check for known qop values (look out for the safari qop quote bug)
  if h[:qop] == 'auth-int'
    digest_h digest_concat(h[:method], h[:uri], digest_h(h[:request_body]))
  else
    digest_h digest_concat(h[:method], h[:uri])
  end
end

# File lib/httpauth/digest.rb, line 183
def response_digest_a2(h)
  if h[:qop] == 'auth-int'
    digest_h ':' + digest_concat(h[:uri], digest_h(h[:response_body]))
  else
    digest_h ':' + h[:uri]
  end
end