class CopyTunerClient::CopyrayMiddleware

def append_css(html, csp_nonce)
  css_tag = helpers.stylesheet_link_tag 'copytuner', media: :all, nonce: csp_nonce
  append_to_html_body(html, css_tag)
end

def append_js(html, csp_nonce)
  json =
    if CopyTunerClient::TranslationLog.initialized?
      CopyTunerClient::TranslationLog.translations.to_json
    else
      '{}'
    end
  append_to_html_body(html, helpers.javascript_tag(<<~SCRIPT, nonce: csp_nonce))
    window.CopyTuner = {
      url: '#{CopyTunerClient.configuration.project_url}',
      data: #{json},
    }
  SCRIPT
  append_to_html_body(html, helpers.javascript_include_tag('copytuner', type: 'module', crossorigin: 'anonymous', nonce: csp_nonce))
end

def append_to_html_body(html, content)
  content = content.html_safe if content.respond_to?(:html_safe)
  return html unless html.include?('</body>')
  position = html.rindex('</body>')
  html.insert(position, content + "\n")
end

def call(env)
  CopyTunerClient::TranslationLog.clear
  status, headers, response = @app.call(env)
  if html_headers?(status, headers) && body = response_body(response)
    csp_nonce = env['action_dispatch.content_security_policy_nonce'] || env['secure_headers_content_security_policy_nonce']
    body = append_css(body, csp_nonce)
    body = append_js(body, csp_nonce)
    content_length = body.bytesize.to_s
    headers['Content-Length'] = content_length
    # maintains compatibility with other middlewares
    if defined?(ActionDispatch::Response::RackBody) && ActionDispatch::Response::RackBody === response
      ActionDispatch::Response.new(status, headers, [body]).to_a
    else
      [status, headers, [body]]
    end
  else
    [status, headers, response]
  end
end

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

def helpers
  ActionController::Base.helpers
end

def html_headers?(status, headers)
  status == 200 &&
  headers['Content-Type'] &&
  headers['Content-Type'].include?('text/html') &&
  !file?(headers)
end

def initialize(app)
  @app = app
end

def response_body(response)
  body = ''
  response.each { |s| body << s.to_s }
  body
end