// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef REMOTING_HOST_PLUGIN_HOST_SCRIPT_OBJECT_H_
#define REMOTING_HOST_PLUGIN_HOST_SCRIPT_OBJECT_H_

#include <string>
#include <vector>

#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/synchronization/cancellation_flag.h"
#include "base/synchronization/lock.h"
#include "base/synchronization/waitable_event.h"
#include "base/string16.h"
#include "base/threading/platform_thread.h"
#include "base/threading/thread.h"
#include "base/time.h"
#include "remoting/base/auto_thread_task_runner.h"
#include "remoting/host/chromoting_host_context.h"
#include "remoting/host/host_key_pair.h"
#include "remoting/host/log_to_server.h"
#include "remoting/host/plugin/host_plugin_utils.h"
#include "remoting/host/setup/daemon_controller.h"
#include "remoting/host/ui_strings.h"
#include "third_party/npapi/bindings/npapi.h"
#include "third_party/npapi/bindings/npfunctions.h"
#include "third_party/npapi/bindings/npruntime.h"

namespace remoting {

// NPAPI plugin implementation for remoting host script object.
// HostNPScriptObject creates threads that are required to run
// ChromotingHost and starts/stops the host on those threads. When
// destroyed it synchronously shuts down the host and all threads.
class HostNPScriptObject {
 public:
  HostNPScriptObject(NPP plugin,
                     NPObject* parent,
                     scoped_refptr<AutoThreadTaskRunner> plugin_task_runner);
  virtual ~HostNPScriptObject();

  // Implementations used to implement the NPObject interface.
  bool HasMethod(const std::string& method_name);
  bool InvokeDefault(const NPVariant* args,
                     uint32_t arg_count,
                     NPVariant* result);
  bool Invoke(const std::string& method_name,
              const NPVariant* args,
              uint32_t arg_count,
              NPVariant* result);
  bool HasProperty(const std::string& property_name);
  bool GetProperty(const std::string& property_name, NPVariant* result);
  bool SetProperty(const std::string& property_name, const NPVariant* value);
  bool RemoveProperty(const std::string& property_name);
  bool Enumerate(std::vector<std::string>* values);

  // Post LogDebugInfo to the correct proxy (and thus, on the correct thread).
  // This should only be called by HostLogHandler. To log to the UI, use the
  // standard LOG(INFO) and it will be sent to this method.
  void PostLogDebugInfo(const std::string& message);

  void SetWindow(NPWindow* np_window);

 private:
  //////////////////////////////////////////////////////////
  // Definitions for It2Me host.

  class It2MeImpl;

  // These state values are duplicated in host_session.js. Remember to update
  // both copies when making changes.
  enum State {
    kDisconnected,
    kStarting,
    kRequestedAccessCode,
    kReceivedAccessCode,
    kConnected,
    kDisconnecting,
    kError,
    kInvalidDomainError
  };

  //////////////////////////////////////////////////////////
  // Plugin methods for It2Me host.

  // Start connection. args are:
  //   string uid, string auth_token
  // No result.
  bool Connect(const NPVariant* args, uint32_t arg_count, NPVariant* result);

  // Disconnect. No arguments or result.
  bool Disconnect(const NPVariant* args, uint32_t arg_count, NPVariant* result);

  // Localize strings. args are:
  //   localize_func - a callback function which returns a localized string for
  //   a given tag name.
  // No result.
  bool Localize(const NPVariant* args, uint32_t arg_count, NPVariant* result);

  //////////////////////////////////////////////////////////
  // Plugin methods for Me2Me host.

  // Returns host name. No arguments.
  bool GetHostName(const NPVariant* args,
                   uint32_t arg_count,
                   NPVariant* result);

  // Calculates PIN hash value to be stored in the config. Args are:
  //   string hostId Host ID.
  //   string pin The PIN.
  // Returns the resulting hash value encoded with Base64.
  bool GetPinHash(const NPVariant* args,
                  uint32_t arg_count,
                  NPVariant* result);

  // Generates new key pair to use for the host. The specified
  // callback is called when when the key is generated. The key is
  // returned in format understood by the host (PublicKeyInfo
  // structure encoded with ASN.1 DER, and then BASE64). Args are:
  //   function(string) callback The callback to be called when done.
  bool GenerateKeyPair(const NPVariant* args,
                       uint32_t arg_count,
                       NPVariant* result);

  // Update host config for Me2Me. Args are:
  //   string config
  //   function(number) done_callback
  bool UpdateDaemonConfig(const NPVariant* args,
                          uint32_t arg_count,
                          NPVariant* result);

  // Loads daemon config. The first argument specifies the callback to be
  // called once the config has been loaded. The config is passed as a JSON
  // formatted string. Args are:
  //   function(string) callback
  bool GetDaemonConfig(const NPVariant* args,
                       uint32_t arg_count,
                       NPVariant* result);

  // Retrieves daemon version. The first argument specifies the callback to be
  // called with the obtained version. The version is passed as a dotted
  // version string, described in daemon_controller.h.
  bool GetDaemonVersion(const NPVariant* args,
                        uint32_t arg_count,
                        NPVariant* result);

  // Retrieves the user's consent to report crash dumps. The first argument
  // specifies the callback to be called with the recorder consent. Possible
  // consent codes are defined in remoting/host/breakpad.h.
  bool GetUsageStatsConsent(const NPVariant* args,
                            uint32_t arg_count,
                            NPVariant* result);

  // Start the daemon process with the specified config. Args are:
  //   string config
  //   function(number) done_callback
  bool StartDaemon(const NPVariant* args,
                   uint32_t arg_count,
                   NPVariant* result);

  // Stop the daemon process. Args are:
  //   function(number) done_callback
  bool StopDaemon(const NPVariant* args, uint32_t arg_count, NPVariant* result);

  //////////////////////////////////////////////////////////
  // Helper methods used by the It2Me host implementation.

  // Notifies OnStateChanged handler of a state change.
  void NotifyStateChanged(State state);

  // If the web-app has registered a callback to be notified of changes to the
  // NAT traversal policy, notify it.
  void NotifyNatPolicyChanged(bool nat_traversal_enabled);

  // Stores the Access Code for the web-app to query.
  void StoreAccessCode(const std::string& access_code,
                       base::TimeDelta access_code_lifetime);

  // Stores the client user's name for the web-app to query.
  void StoreClientUsername(const std::string& client_username);

  // Used to generate localized strings to pass to the It2Me host core.
  void LocalizeStrings(NPObject* localize_func);

  // Helper function for executing InvokeDefault on an NPObject that performs
  // a string->string mapping without substitution. Stores the translation in
  // |result| and returns true on success, or leaves it unchanged and returns
  // false on failure.
  bool LocalizeString(NPObject* localize_func, const char* tag,
                      string16* result);

  // Helper function for executing InvokeDefault on an NPObject that performs
  // a string->string mapping with one substitution. Stores the translation in
  // |result| and returns true on success, or leaves it unchanged and returns
  // false on failure.
  bool LocalizeStringWithSubstitution(NPObject* localize_func,
                                      const char* tag,
                                      const char* substitution,
                                      string16* result);

  //////////////////////////////////////////////////////////
  // Helper methods for Me2Me host.

  // Helpers for GenerateKeyPair().
  void DoGenerateKeyPair(const ScopedRefNPObject& callback);
  void InvokeGenerateKeyPairCallback(const ScopedRefNPObject& callback,
                                     const std::string& private_key,
                                     const std::string& public_key);


  // Callback handler for SetConfigAndStart(), Stop(), SetPin() and
  // SetUsageStatsConsent() in DaemonController.
  void InvokeAsyncResultCallback(const ScopedRefNPObject& callback,
                                 DaemonController::AsyncResult result);

  // Callback handler for DaemonController::GetConfig().
  void InvokeGetDaemonConfigCallback(const ScopedRefNPObject& callback,
                                     scoped_ptr<base::DictionaryValue> config);

  // Callback handler for DaemonController::GetVersion().
  void InvokeGetDaemonVersionCallback(const ScopedRefNPObject& callback,
                                      const std::string& version);

  // Callback handler for DaemonController::GetUsageStatsConsent().
  void InvokeGetUsageStatsConsentCallback(const ScopedRefNPObject& callback,
                                          bool supported,
                                          bool allowed,
                                          bool set_by_policy);

  //////////////////////////////////////////////////////////
  // Basic helper methods used for both It2Me and Me2me.

  // Call LogDebugInfo handler if there is one.
  // This must be called on the correct thread.
  void LogDebugInfo(const std::string& message);

  // Helper function for executing InvokeDefault on an NPObject, and ignoring
  // the return value.
  bool InvokeAndIgnoreResult(NPObject* func,
                             const NPVariant* args,
                             uint32_t arg_count);

  // Set an exception for the current call.
  void SetException(const std::string& exception_string);

  //////////////////////////////////////////////////////////
  // Plugin state variables shared between It2Me and Me2Me.

  NPP plugin_;
  NPObject* parent_;
  scoped_refptr<AutoThreadTaskRunner> plugin_task_runner_;

  // True if we're in the middle of handling a log message.
  bool am_currently_logging_;

  ScopedRefNPObject log_debug_info_func_;

  //////////////////////////////////////////////////////////
  // It2Me host state.

  // Internal implementation of the It2Me host function.
  scoped_refptr<It2MeImpl> it2me_impl_;

  // Cached, read-only copies of |it2me_impl_| session state.
  State state_;
  std::string access_code_;
  base::TimeDelta access_code_lifetime_;
  std::string client_username_;

  // Localized strings for use by the |it2me_impl_| UI.
  UiStrings ui_strings_;

  // Callbacks to notify in response to |it2me_impl_| events.
  ScopedRefNPObject on_nat_traversal_policy_changed_func_;
  ScopedRefNPObject on_state_changed_func_;

  //////////////////////////////////////////////////////////
  // Me2Me host state.

  // Platform-specific installation & configuration implementation.
  scoped_ptr<DaemonController> daemon_controller_;

  // TODO(sergeyu): Replace this thread with
  // SequencedWorkerPool. Problem is that SequencedWorkerPool relies
  // on MessageLoopProxy::current().
  scoped_refptr<AutoThreadTaskRunner> worker_thread_;

  //////////////////////////////////////////////////////////
  // Plugin state used for both Ir2Me and Me2Me.

  // Used to cancel pending tasks for this object when it is destroyed.
  base::WeakPtrFactory<HostNPScriptObject> weak_factory_;
  base::WeakPtr<HostNPScriptObject> weak_ptr_;

  DISALLOW_COPY_AND_ASSIGN(HostNPScriptObject);
};

}  // namespace remoting

#endif  // REMOTING_HOST_PLUGIN_HOST_SCRIPT_OBJECT_H_
