// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_COMPONENTS_IO_THREAD_IOS_IO_THREAD_H_
#define IOS_COMPONENTS_IO_THREAD_IOS_IO_THREAD_H_

#include <stddef.h>
#include <stdint.h>

#include <map>
#include <memory>
#include <set>
#include <string>
#include <vector>

#import "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "components/prefs/pref_member.h"
#include "ios/web/public/thread/web_thread_delegate.h"
#include "net/base/network_change_notifier.h"
#include "net/http/http_network_session.h"

class PrefProxyConfigTracker;
class PrefService;

namespace net {
class HttpAuthHandlerFactory;
class HttpAuthPreferences;
class LoggingNetworkChangeObserver;
class NetLog;
class NetworkDelegate;
class ProxyConfigService;
class URLRequestContext;
class URLRequestContextGetter;
}  // namespace net

namespace io_thread {

class SystemURLRequestContextGetter;

// Contains state associated with, initialized and cleaned up on, and
// primarily used on, the IO thread.
//
// If you are looking to interact with the IO thread (e.g. post tasks
// to it or check if it is the current thread), see web::WebThread.
class IOSIOThread : public web::WebThreadDelegate {
 public:
  struct Globals {
    template <typename T>
    class Optional {
     public:
      Optional() : set_(false) {}

      void set(T value) {
        set_ = true;
        value_ = value;
      }
      void CopyToIfSet(T* value) const {
        if (set_) {
          *value = value_;
        }
      }

     private:
      bool set_;
      T value_;
    };

    class SystemRequestContextLeakChecker {
     public:
      explicit SystemRequestContextLeakChecker(Globals* globals);
      ~SystemRequestContextLeakChecker();

     private:
      const raw_ptr<Globals> globals_;
    };

    Globals();
    ~Globals();

    std::unique_ptr<net::HttpAuthPreferences> http_auth_preferences;
    std::unique_ptr<net::URLRequestContext> system_request_context;
    SystemRequestContextLeakChecker system_request_context_leak_checker;
  };

  // `net_log` must either outlive the IOSIOThread or be NULL.
  IOSIOThread(PrefService* local_state, net::NetLog* net_log);

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

  ~IOSIOThread() override;

  // Initialize the IO thread with blocking allowed.
  void InitOnIO();

  // Can only be called on the IO thread.
  Globals* globals();

  // Allows overriding Globals in tests where IOSIOThread::Init() and
  // IOSIOThread::CleanUp() are not called.  This allows for injecting mocks
  // into IOSIOThread global objects.
  void SetGlobalsForTesting(Globals* globals);

  net::NetLog* net_log();

  // Handles changing to On The Record mode, discarding confidential data.
  void ChangedToOnTheRecord();

  // Returns a getter for the URLRequestContext.  Only called on the UI thread.
  net::URLRequestContextGetter* system_url_request_context_getter();

  // Clears the host cache.  Intended to be used to prevent exposing recently
  // visited sites on about:net-internals/#dns and about:dns pages.  Must be
  // called on the IO thread.
  void ClearHostCache();

  const net::HttpNetworkSessionParams& NetworkSessionParams() const;

  const net::QuicParams& quic_params() const { return quic_params_; }

  std::unique_ptr<net::HttpAuthHandlerFactory> CreateHttpAuthHandlerFactory();

 protected:
  // A string describing the current application version. For example: "stable"
  // or "dev". An empty string is an acceptable value. This string is used to
  // build the user agent id for QUIC.
  virtual std::string GetChannelString() const = 0;

  // Subclasses must return a NetworkDelegate to be used for
  // BrowserState-agnostic network events.
  virtual std::unique_ptr<net::NetworkDelegate>
  CreateSystemNetworkDelegate() = 0;

 private:
  // Provide SystemURLRequestContextGetter with access to
  // InitSystemRequestContext().
  friend class SystemURLRequestContextGetter;

  // WebThreadDelegate implementation, runs on the IO thread.
  // This handles initialization and destruction of state that must
  // live on the IO thread.
  void Init() override;
  void CleanUp() override;

  // Sets up HttpAuthPreferences and HttpAuthHandlerFactory on Globals.
  void CreateDefaultAuthPreferences();

  // Discards confidential data. To be called on IO thread only.
  void ChangedToOnTheRecordOnIOThread();

  std::unique_ptr<net::URLRequestContext> ConstructSystemRequestContext();

  // The NetLog is owned by the application context, to allow logging from other
  // threads during shutdown, but is used most frequently on the IO thread.
  raw_ptr<net::NetLog> net_log_;

  // These member variables are basically global, but their lifetimes are tied
  // to the IOSIOThread.  IOSIOThread owns them all, despite not using
  // scoped_ptr. This is because the destructor of IOSIOThread runs on the
  // wrong thread.  All member variables should be deleted in CleanUp().

  // These member variables are initialized in Init() and do not change for the
  // lifetime of the IO thread.

  raw_ptr<Globals> globals_;

  net::HttpNetworkSessionParams params_;

  net::QuicParams quic_params_;

  // Observer that logs network changes to the NetLog.
  std::unique_ptr<net::LoggingNetworkChangeObserver> network_change_observer_;

  // These member variables are initialized by a task posted to the IO thread,
  // which gets posted by calling certain member functions of IOSIOThread.
  std::unique_ptr<net::ProxyConfigService> system_proxy_config_service_;

  std::unique_ptr<PrefProxyConfigTracker> pref_proxy_config_tracker_;

  scoped_refptr<SystemURLRequestContextGetter>
      system_url_request_context_getter_;

  base::WeakPtrFactory<IOSIOThread> weak_factory_;
};

}  // namespace io_thread

#endif  // IOS_COMPONENTS_IO_THREAD_IOS_IO_THREAD_H_