module Qeweney::RequestInfoClassMethods

def parse_form_data(body, headers)
  case (content_type = headers['content-type'])
  when /^multipart\/form\-data; boundary=([^\s]+)/
    boundary = "--#{Regexp.last_match(1)}"
    parse_multipart_form_data(body, boundary)
  when /^application\/x-www-form-urlencoded/
    parse_urlencoded_form_data(body)
  else
    raise "Unsupported form data content type: #{content_type}"
  end
end

def parse_multipart_form_data(body, boundary)
  parts = body.split(boundary)
  parts.each_with_object({}) do |p, h|
    next if p.empty? || p == "--\r\n"
    # remove post-boundary \r\n
    p.slice!(0, 2)
    parse_multipart_form_data_part(p, h)
  end
end

def parse_multipart_form_data_part(part, hash)
  body, headers = parse_multipart_form_data_part_headers(part)
  disposition = headers['content-disposition'] || ''
  name = (disposition =~ /name="([^"]+)"/) ? Regexp.last_match(1) : nil
  filename = (disposition =~ /filename="([^"]+)"/) ? Regexp.last_match(1) : nil
  if filename
    hash[name] = { filename: filename, content_type: headers['content-type'], data: body }
  else
    hash[name] = body
  end
end

def parse_multipart_form_data_part_headers(part)
  headers = {}
  while true
    idx = part.index("\r\n")
    break unless idx
    header = part[0, idx]
    part.slice!(0, idx + 2)
    break if header.empty?
    next unless header =~ /^([^\:]+)\:\s?(.+)$/
    headers[Regexp.last_match(1).downcase] = Regexp.last_match(2)
  end
  # remove trailing \r\n
  part.slice!(part.size - 2, 2)
  [part, headers]
end

def parse_urlencoded_form_data(body)
  return {} unless body
  body.force_encoding(Encoding::UTF_8) unless body.encoding == Encoding::UTF_8
  body.split('&').each_with_object({}) do |i, m|
    raise 'Invalid parameter format' unless i =~ PARAMETER_RE
    k = Regexp.last_match(1)
    raise 'Invalid parameter size' if k.size > MAX_PARAMETER_NAME_SIZE
    v = Regexp.last_match(2)
    raise 'Invalid parameter size' if v.size > MAX_PARAMETER_VALUE_SIZE
    m[EscapeUtils.unescape_uri(k)] = EscapeUtils.unescape_uri(v)
  end
end