class Bullet::Rack

def append_to_html_body(response_body, content)
  body = response_body.dup
  content = content.html_safe if content.respond_to?(:html_safe)
  if body.include?('</body>')
    position = body.rindex('</body>')
    body.insert(position, content)
  else
    body << content
  end
end

def call(env)
  return @app.call(env) unless Bullet.enable?
  Bullet.start_request
  status, headers, response = @app.call(env)
  response_body = nil
  if Bullet.notification? || Bullet.always_append_html_body
    request = ::Rack::Request.new(env)
    if Bullet.inject_into_page? && !skip_html_injection?(request) && !file?(headers) && !sse?(headers) && !empty?(response) && status == 200
      if html_request?(headers, response)
        response_body = response_body(response)
        with_security_policy_nonce(headers) do |nonce|
          response_body = append_to_html_body(response_body, footer_note(nonce)) if Bullet.add_footer
          response_body = append_to_html_body(response_body, Bullet.gather_inline_notifications)
          if Bullet.add_footer && !Bullet.skip_http_headers
            response_body = append_to_html_body(response_body, xhr_script(nonce))
          end
        end
        headers['Content-Length'] = response_body.bytesize.to_s
      elsif !Bullet.skip_http_headers
        set_header(headers, 'X-bullet-footer-text', Bullet.footer_info.uniq) if Bullet.add_footer
        set_header(headers, 'X-bullet-console-text', Bullet.text_notifications) if Bullet.console_enabled?
      end
    end
    Bullet.perform_out_of_channel_notifications(env)
  end
  [status, headers, response_body ? [response_body] : response]
ensure
  Bullet.end_request
end

def empty?(response)
  # response may be ["Not Found"], ["Move Permanently"], etc, but
  # those should not happen if the status is 200
  return true if !response.respond_to?(:body) && !response.respond_to?(:first)
  body = response_body(response)
  body.nil? || body.empty?
end

def file?(headers)
  headers['Content-Transfer-Encoding'] == 'binary' || headers['Content-Disposition']
end

def footer_console_message(nonce = nil)
  if Bullet.console_enabled?
    footer = %(<br/><span id="console-message">See 'Uniform Notifier' in JS Console for Stacktrace</span>)
    css = "details#bullet-footer #console-message {font-style: italic;}"
    style =
      if nonce
        %(<style type="text/css" nonce="#{nonce}">#{css}</style>)
      else
        %(<style type="text/css">#{css}</style>)
      end
    footer + style
  end
end

def footer_note(nonce = nil)
  %(<details id="bullet-footer" data-is-bullet-footer><summary>Bullet Warnings</summary><div>#{Bullet.footer_info.uniq.join('<br>')}#{footer_console_message(nonce)}</div>#{footer_style(nonce)}</details>)
end

def footer_style(nonce = nil)
  css = <<~CSS
    details#bullet-footer {cursor: pointer; position: fixed; left: 0px; bottom: 0px; z-index: 9999; background: #fdf2f2; color: #9b1c1c; font-size: 12px; border-radius: 0px 8px 0px 0px; border: 1px solid #9b1c1c;}
    details#bullet-footer summary {font-weight: 600; padding: 2px 8px;}
    details#bullet-footer div {padding: 8px; border-top: 1px solid #9b1c1c;}
  CSS
  if nonce
    %(<style type="text/css" nonce="#{nonce}">#{css}</style>)
  else
    %(<style type="text/css">#{css}</style>)
  end
end

def html_request?(headers, response)
  headers['Content-Type']&.include?('text/html')
end

def initialize(app)
  @app = app
end

def response_body(response)
  if response.respond_to?(:body)
    Array === response.body ? response.body.first : response.body
  elsif response.respond_to?(:first)
    response.first
  end
end

def set_header(headers, header_name, header_array)
  # Many proxy applications such as Nginx and AWS ELB limit
  # the size a header to 8KB, so truncate the list of reports to
  # be under that limit
  header_array.pop while JSON.generate(header_array).length > 8 * 1024
  headers[header_name] = JSON.generate(header_array)
end

def simple_parse_query_string(query_string)
  params = {}
  query_string.split('&').each do |pair|
    key, value = pair.split('=', 2).map { |s| CGI.unescape(s) }
    params[key] = value if key && !key.empty?
  end
  params
end

def skip_html_injection?(request)
  query_string = request.env['QUERY_STRING']
  return false if query_string.nil? || query_string.empty?
  params = simple_parse_query_string(query_string)
  params['skip_html_injection'] == 'true'
end

def sse?(headers)
  headers['Content-Type'] == 'text/event-stream'
end

def with_security_policy_nonce(headers)
  csp = headers['Content-Security-Policy'] || headers['Content-Security-Policy-Report-Only'] || ''
  matched = csp.match(NONCE_MATCHER)
  nonce = matched[:nonce] if matched
  if nonce
    console_enabled = UniformNotifier.console
    alert_enabled = UniformNotifier.alert
    UniformNotifier.console = { attributes: { nonce: nonce } } if console_enabled
    UniformNotifier.alert = { attributes: { nonce: nonce } } if alert_enabled
    yield nonce
    UniformNotifier.console = console_enabled
    UniformNotifier.alert = alert_enabled
  else
    yield
  end
end

def xhr_script(nonce = nil)
  script = File.read("#{__dir__}/bullet_xhr.js")
  if nonce
    "<script type='text/javascript' nonce='#{nonce}'>#{script}</script>"
  else
    "<script type='text/javascript'>#{script}</script>"
  end
end