class CGI

def self.accept_charset
  @@accept_charset
end

def self.accept_charset=(accept_charset)
  @@accept_charset=accept_charset
end

def self.parse(query)
  params = {}
  query.split(/[&;]/).each do |pairs|
    key, value = pairs.split('=',2).collect{|v| CGI.unescape(v) }
    next unless key
    params[key] ||= []
    params[key].push(value) if value
  end
  params.default=[].freeze
  params
end

def _header_for_hash(options)  #:nodoc:
  buf = ''.dup
  ## add charset to option['type']
  options['type'] ||= 'text/html'
  charset = options.delete('charset')
  options['type'] += "; charset=#{charset}" if charset
  ## NPH
  options.delete('nph') if defined?(MOD_RUBY)
  if options.delete('nph') || nph?()
    protocol = _no_crlf_check($CGI_ENV['SERVER_PROTOCOL']) || 'HTTP/1.0'
    status = options.delete('status')
    status = HTTP_STATUS[status] || _no_crlf_check(status) || '200 OK'
    buf << "#{protocol} #{status}#{EOL}"
    buf << "Date: #{CGI.rfc1123_date(Time.now)}#{EOL}"
    options['server'] ||= $CGI_ENV['SERVER_SOFTWARE'] || ''
    options['connection'] ||= 'close'
  end
  ## common headers
  status = options.delete('status')
  buf << "Status: #{HTTP_STATUS[status] || _no_crlf_check(status)}#{EOL}" if status
  server = options.delete('server')
  buf << "Server: #{_no_crlf_check(server)}#{EOL}" if server
  connection = options.delete('connection')
  buf << "Connection: #{_no_crlf_check(connection)}#{EOL}" if connection
  type = options.delete('type')
  buf << "Content-Type: #{_no_crlf_check(type)}#{EOL}" #if type
  length = options.delete('length')
  buf << "Content-Length: #{_no_crlf_check(length)}#{EOL}" if length
  language = options.delete('language')
  buf << "Content-Language: #{_no_crlf_check(language)}#{EOL}" if language
  expires = options.delete('expires')
  buf << "Expires: #{CGI.rfc1123_date(expires)}#{EOL}" if expires
  ## cookie
  if cookie = options.delete('cookie')
    case cookie
    when String, Cookie
      buf << "Set-Cookie: #{_no_crlf_check(cookie)}#{EOL}"
    when Array
      arr = cookie
      arr.each {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" }
    when Hash
      hash = cookie
      hash.each_value {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" }
    end
  end
  if @output_cookies
    @output_cookies.each {|c| buf << "Set-Cookie: #{_no_crlf_check(c)}#{EOL}" }
  end
  ## other headers
  options.each do |key, value|
    buf << "#{_no_crlf_check(key)}: #{_no_crlf_check(value)}#{EOL}"
  end
  return buf
end # _header_for_hash

def _header_for_modruby(buf)  #:nodoc:
  request = Apache::request
  buf.scan(/([^:]+): (.+)#{EOL}/o) do |name, value|
    $stderr.printf("name:%s value:%s\n", name, value) if $DEBUG
    case name
    when 'Set-Cookie'
      request.headers_out.add(name, value)
    when /^status$/i
      request.status_line = value
      request.status = value.to_i
    when /^content-type$/i
      request.content_type = value
    when /^content-encoding$/i
      request.content_encoding = value
    when /^location$/i
      request.status = 302 if request.status == 200
      request.headers_out[name] = value
    else
      request.headers_out[name] = value
    end
  end
  request.send_http_header
  return ''
end

def _header_for_string(content_type) #:nodoc:
  buf = ''.dup
  if nph?()
    buf << "#{_no_crlf_check($CGI_ENV['SERVER_PROTOCOL']) || 'HTTP/1.0'} 200 OK#{EOL}"
    buf << "Date: #{CGI.rfc1123_date(Time.now)}#{EOL}"
    buf << "Server: #{_no_crlf_check($CGI_ENV['SERVER_SOFTWARE'])}#{EOL}"
    buf << "Connection: close#{EOL}"
  end
  buf << "Content-Type: #{_no_crlf_check(content_type)}#{EOL}"
  if @output_cookies
    @output_cookies.each {|cookie| buf << "Set-Cookie: #{_no_crlf_check(cookie)}#{EOL}" }
  end
  return buf
end # _header_for_string

def _no_crlf_check(str)
  if str
    str = str.to_s
    raise "A HTTP status or header field must not include CR and LF" if str =~ /[\r\n]/
    str
  else
    nil
  end
end

def env_table
  ENV
end

def http_header(options='text/html')
  if options.is_a?(String)
    content_type = options
    buf = _header_for_string(content_type)
  elsif options.is_a?(Hash)
    if options.size == 1 && options.has_key?('type')
      content_type = options['type']
      buf = _header_for_string(content_type)
    else
      buf = _header_for_hash(options.dup)
    end
  else
    raise ArgumentError.new("expected String or Hash but got #{options.class}")
  end
  if defined?(MOD_RUBY)
    _header_for_modruby(buf)
    return ''
  else
    buf << EOL    # empty line of separator
    return buf
  end
end # http_header()