// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_ANDROID_CUSTOMTABS_DETACHED_RESOURCE_REQUEST_H_
#define CHROME_BROWSER_ANDROID_CUSTOMTABS_DETACHED_RESOURCE_REQUEST_H_

#include <memory>
#include <optional>
#include <string>
#include <vector>

#include "base/functional/callback.h"
#include "base/functional/callback_helpers.h"
#include "base/time/time.h"
#include "net/url_request/referrer_policy.h"
#include "services/network/public/mojom/url_response_head.mojom-forward.h"
#include "url/gurl.h"

namespace content {
class BrowserContext;
}  // namespace content

namespace net {
struct RedirectInfo;
}  // namespace net

namespace network {
class SimpleURLLoader;
}  // namespace network

namespace customtabs {

// Detached resource request, that is a resource request initiated from the
// browser process, and which starts detached from any client.
//
// It is intended to provide "detached" request capabilities from the browser
// process, that is like <a ping> or <link rel="prefetch">.
//
// This is a UI thread class.
class DetachedResourceRequest {
 public:
  static constexpr int kMaxResponseSize = 500 * 1024;

  // The motivation of the resource request, used for histograms reporting.
  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.customtabs
  // GENERATED_JAVA_CLASS_NAME_OVERRIDE: DetachedResourceRequestMotivation
  enum class Motivation { kParallelRequest, kResourcePrefetch };

  using OnResultCallback = base::OnceCallback<void(int net_error)>;

  DetachedResourceRequest(const DetachedResourceRequest&) = delete;
  DetachedResourceRequest& operator=(const DetachedResourceRequest&) = delete;

  ~DetachedResourceRequest();

  // Creates a detached request to a `url`, with a given initiating URL,
  // `site_for_referrer`. Called on the UI thread.
  // Optional `cb` to get notified about the fetch result.
  static void CreateAndStart(content::BrowserContext* browser_context,
                             const GURL& url,
                             const GURL& site_for_referrer,
                             net::ReferrerPolicy referer_policy,
                             Motivation motivation,
                             const std::string& package_name,
                             OnResultCallback cb = base::DoNothing());

 private:
  DetachedResourceRequest(const GURL& url,
                          const GURL& site_for_referrer,
                          net::ReferrerPolicy referer_policy,
                          Motivation motivation,
                          const std::string& package_name,
                          OnResultCallback cb);

  static void Start(std::unique_ptr<DetachedResourceRequest> request,
                    content::BrowserContext* browser_context);
  void OnRedirectCallback(const GURL& url_before_redirect,
                          const net::RedirectInfo& redirect_info,
                          const network::mojom::URLResponseHead& response_head,
                          std::vector<std::string>* to_be_removed_headers);
  void OnResponseCallback(std::optional<std::string> response_body);

  const GURL url_;
  const GURL site_for_referrer_;
  base::TimeTicks start_time_;
  Motivation motivation_;
  OnResultCallback cb_;
  std::unique_ptr<network::SimpleURLLoader> url_loader_;
  int redirects_;
  bool is_from_aga_;
};

}  // namespace customtabs

#endif  // CHROME_BROWSER_ANDROID_CUSTOMTABS_DETACHED_RESOURCE_REQUEST_H_