class DataStyleSanitizer::Middleware

def call(env)
  status, headers, response = @app.call(env)
  if html_response?(headers)
    body = +""
    response.each { |part| body << part }
    nonce = extract_nonce_from_env(env)
    processed = Processor.new(body, nonce: nonce).process
    headers["Content-Length"] = processed.bytesize.to_s
    [status, headers, [processed]]
  else
    [status, headers, response]
  end
end

def call(env)
  status, headers, response = @app.call(env)
  if headers["Content-Type"]&.include?("text/html")
    body = +""
    response.each { |part| body << part }
    nonce = extract_nonce(env)
    new_body = DataStyleSanitizer.process(body, nonce: nonce)
    headers["Content-Length"] = new_body.bytesize.to_s
    [status, headers, [new_body]]
  else
    [status, headers, response]
  end
end

def extract_nonce(env)
  if env.respond_to?(:dig)
    env.dig("action_dispatch.content_security_policy_nonce", :style)
  else
    # get nonce from meta tag
    # This is a fallback for older versions of Rails
    meta_tag = env["rack.session"]&.dig("meta_tags", "csp-nonce")
    if meta_tag
      meta_tag.match(/nonce="([^"]+)"/)[1] if /nonce="([^"]+)"/.match?(meta_tag)
    end
  end
end

def extract_nonce_from_env(env)
  if env["action_dispatch.content_security_policy_nonce"].respond_to?(:call)
    env["action_dispatch.content_security_policy_nonce"].call(:style)
  end
end

def html_response?(headers)
  headers["Content-Type"]&.include?("text/html")
end

def initialize(app)
  @app = app
end

def initialize(app)
  @app = app
end