// Copyright 2014 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.

#include "ppapi/tests/test_message_handler.h"

#include <string.h>
#include <algorithm>
#include <map>
#include <sstream>

#include "ppapi/c/pp_var.h"
#include "ppapi/c/ppb_file_io.h"
#include "ppapi/c/ppp_message_handler.h"
#include "ppapi/cpp/file_io.h"
#include "ppapi/cpp/file_ref.h"
#include "ppapi/cpp/file_system.h"
#include "ppapi/cpp/instance.h"
#include "ppapi/cpp/module_impl.h"
#include "ppapi/cpp/var.h"
#include "ppapi/cpp/var_array.h"
#include "ppapi/cpp/var_array_buffer.h"
#include "ppapi/cpp/var_dictionary.h"
#include "ppapi/tests/pp_thread.h"
#include "ppapi/tests/test_utils.h"
#include "ppapi/tests/testing_instance.h"

// Windows defines 'PostMessage', so we have to undef it.
#ifdef PostMessage
#undef PostMessage
#endif

REGISTER_TEST_CASE(MessageHandler);

namespace {

// Created and destroyed on the main thread. All public methods should be called
// on the main thread. Most data members are only accessed on the main thread.
// (Though it handles messages on the background thread).
class EchoingMessageHandler {
 public:
  explicit EchoingMessageHandler(PP_Instance instance,
                                 const pp::MessageLoop& loop)
      : pp_instance_(instance),
        message_handler_loop_(loop),
        ppb_messaging_if_(static_cast<const PPB_Messaging_1_1*>(
            pp::Module::Get()->GetBrowserInterface(
                PPB_MESSAGING_INTERFACE_1_1))),
        ppp_message_handler_if_(),
        is_registered_(false),
        test_finished_event_(instance),
        destroy_event_(instance) {
    AssertOnMainThread();
    ppp_message_handler_if_.HandleMessage = &HandleMessage;
    ppp_message_handler_if_.HandleBlockingMessage = &HandleBlockingMessage;
    ppp_message_handler_if_.Destroy = &Destroy;
  }
  void Register() {
    AssertOnMainThread();
    assert(!is_registered_);
    int32_t result = ppb_messaging_if_->RegisterMessageHandler(
        pp_instance_,
        this,
        &ppp_message_handler_if_,
        message_handler_loop_.pp_resource());
    if (result == PP_OK) {
      is_registered_ = true;
    } else {
      std::ostringstream stream;
      stream << "Failed to register message handler; got error " << result;
      AddError(stream.str());
      test_finished_event_.Signal();
    }
    // Note, at this point, we can't safely read or write errors_ until we wait
    // on destroy_event_.
  }
  void Unregister() {
    AssertOnMainThread();
    assert(is_registered_);
    ppb_messaging_if_->UnregisterMessageHandler(pp_instance_);
    is_registered_ = false;
  }
  void WaitForTestFinishedMessage() {
    test_finished_event_.Wait();
    test_finished_event_.Reset();
  }
  // Wait for Destroy() to be called on the MessageHandler thread. When it's
  // done, return any errors that occurred during the time the MessageHandler
  // was getting messages.
  std::string WaitForDestroy() {
    AssertOnMainThread();
    // If we haven't called Unregister, we'll be waiting forever.
    assert(!is_registered_);
    destroy_event_.Wait();
    destroy_event_.Reset();
    // Now that we know Destroy() has been called, we know errors_ isn't being
    // written on the MessageHandler thread anymore. So we can safely read it
    // here on the main thread (since destroy_event_ gave us a memory barrier).
    std::string temp_errors;
    errors_.swap(temp_errors);
    return temp_errors;
  }
 private:
  static void AssertOnMainThread() {
    assert(pp::MessageLoop::GetForMainThread() ==
           pp::MessageLoop::GetCurrent());
  }
  void AddError(const std::string& error) {
    if (!error.empty()) {
      if (!errors_.empty())
        errors_ += "<p>";
      errors_ += error;
    }
  }
  static void HandleMessage(PP_Instance instance,
                            void* user_data,
                            struct PP_Var message_data) {
    EchoingMessageHandler* thiz =
        static_cast<EchoingMessageHandler*>(user_data);
    if (pp::MessageLoop::GetCurrent() != thiz->message_handler_loop_)
      thiz->AddError("HandleMessage was called on the wrong thread!");
    if (instance != thiz->pp_instance_)
      thiz->AddError("HandleMessage was passed the wrong instance!");
    pp::Var var(message_data);
    if (var.is_string() && var.AsString() == "FINISHED_TEST")
      thiz->test_finished_event_.Signal();
    else
      thiz->ppb_messaging_if_->PostMessage(instance, message_data);
  }

  static PP_Var HandleBlockingMessage(PP_Instance instance,
                                      void* user_data,
                                      struct PP_Var message_data) {
    EchoingMessageHandler* thiz =
        static_cast<EchoingMessageHandler*>(user_data);
    if (pp::MessageLoop::GetCurrent() != thiz->message_handler_loop_)
      thiz->AddError("HandleBlockingMessage was called on the wrong thread!");
    if (instance != thiz->pp_instance_)
      thiz->AddError("HandleBlockingMessage was passed the wrong instance!");

    // The PP_Var we are passed is an in-parameter, so the browser is not
    // giving us a ref-count. The ref-count it has will be decremented after we
    // return. But we need to add a ref when returning a PP_Var, to pass to the
    // caller.
    pp::Var take_ref(message_data);
    take_ref.Detach();
    return message_data;
  }

  static void Destroy(PP_Instance instance, void* user_data) {
    EchoingMessageHandler* thiz =
        static_cast<EchoingMessageHandler*>(user_data);
    if (pp::MessageLoop::GetCurrent() != thiz->message_handler_loop_)
      thiz->AddError("Destroy was called on the wrong thread!");
    if (instance != thiz->pp_instance_)
      thiz->AddError("Destroy was passed the wrong instance!");
    thiz->destroy_event_.Signal();
  }

  // These data members are initialized on the main thread, but don't change for
  // the life of the object, so are safe to access on the background thread,
  // because there will be a memory barrier before the the MessageHandler calls
  // are invoked.
  const PP_Instance pp_instance_;
  const pp::MessageLoop message_handler_loop_;
  const pp::MessageLoop main_loop_;
  const PPB_Messaging_1_1* const ppb_messaging_if_;
  // Spiritually, this member is const, but we can't initialize it in C++03,
  // so it has to be non-const to be set in the constructor body.
  PPP_MessageHandler_0_1 ppp_message_handler_if_;

  // is_registered_ is only read/written on the main thread.
  bool is_registered_;

  // errors_ is written on the MessageHandler thread. When Destroy() is
  // called, we stop writing to errors_ and signal destroy_event_. This causes
  // a memory barrier, so it's safe to read errors_ after that.
  std::string errors_;
  NestedEvent test_finished_event_;
  NestedEvent destroy_event_;

  // Undefined & private to disallow copy and assign.
  EchoingMessageHandler(const EchoingMessageHandler&);
  EchoingMessageHandler& operator=(const EchoingMessageHandler&);
};

void FakeHandleMessage(PP_Instance instance,
                       void* user_data,
                       struct PP_Var message_data) {}
PP_Var FakeHandleBlockingMessage(PP_Instance instance,
                                 void* user_data,
                                 struct PP_Var message_data) {
  return PP_MakeUndefined();
}
void FakeDestroy(PP_Instance instance, void* user_data) {}

}  // namespace

TestMessageHandler::TestMessageHandler(TestingInstance* instance)
    : TestCase(instance),
      ppb_messaging_if_(NULL),
      handler_thread_(instance) {
}

TestMessageHandler::~TestMessageHandler() {
  handler_thread_.Join();
}

bool TestMessageHandler::Init() {
  ppb_messaging_if_ = static_cast<const PPB_Messaging_1_1*>(
      pp::Module::Get()->GetBrowserInterface(PPB_MESSAGING_INTERFACE_1_1));
  return ppb_messaging_if_ &&
         CheckTestingInterface() &&
         handler_thread_.Start();
}

void TestMessageHandler::RunTests(const std::string& filter) {
  RUN_TEST(RegisterErrorConditions, filter);
  RUN_TEST(PostMessageAndAwaitResponse, filter);
}

void TestMessageHandler::HandleMessage(const pp::Var& message_data) {
  // All messages should go to the background thread message handler.
  assert(false);
}

std::string TestMessageHandler::TestRegisterErrorConditions() {
  {
    // Test registering with the main thread as the message loop.
    PPP_MessageHandler_0_1 fake_ppp_message_handler = {
      &FakeHandleMessage, &FakeHandleBlockingMessage, &FakeDestroy
    };
    pp::MessageLoop main_loop = pp::MessageLoop::GetForMainThread();
    int32_t result = ppb_messaging_if_->RegisterMessageHandler(
        instance()->pp_instance(),
        reinterpret_cast<void*>(0xdeadbeef),
        &fake_ppp_message_handler,
        main_loop.pp_resource());
    ASSERT_EQ(PP_ERROR_WRONG_THREAD, result);
  }
  {
    // Test registering with incomplete PPP_Messaging interface.
    PPP_MessageHandler_0_1 bad_ppp_ifs[] = {
        { NULL, &FakeHandleBlockingMessage, &FakeDestroy },
        { &FakeHandleMessage, NULL, &FakeDestroy },
        { &FakeHandleMessage, &FakeHandleBlockingMessage, NULL }};
    for (size_t i = 0; i < sizeof(bad_ppp_ifs)/sizeof(bad_ppp_ifs[0]); ++i) {
      int32_t result = ppb_messaging_if_->RegisterMessageHandler(
          instance()->pp_instance(),
          reinterpret_cast<void*>(0xdeadbeef),
          &bad_ppp_ifs[i],
          handler_thread_.message_loop().pp_resource());
      ASSERT_EQ(PP_ERROR_BADARGUMENT, result);
    }
  }
  PASS();
}

std::string TestMessageHandler::TestPostMessageAndAwaitResponse() {
  EchoingMessageHandler handler(instance()->pp_instance(),
                                handler_thread_.message_loop());
  handler.Register();
  std::string js_code("var plugin = document.getElementById('plugin');\n");
  js_code += "var result = undefined;\n";
  const char* const values_to_test[] = {
      "5",
      "undefined",
      "1.5",
      "'hello'",
      "{'key': 'value', 'array_key': [1, 2, 3, 4, 5]}",
      NULL
  };
  for (size_t i = 0; values_to_test[i]; ++i) {
    js_code += "result = plugin.postMessageAndAwaitResponse(";
    js_code +=     values_to_test[i];
    js_code += ");\n";
    js_code += "if (!deepCompare(result, ";
    js_code +=     values_to_test[i];
    js_code += "))\n";
    js_code += "  InternalError(\" Failed postMessageAndAwaitResponse for: ";
    js_code +=      values_to_test[i];
    js_code +=    " result: \" + result);\n";
  }
  // TODO(dmichael): Setting a property uses GetInstanceObject, which sends sync
  // message, which can get interrupted with message to eval script, etc.
  // FINISHED_WAITING message can therefore jump ahead. This test is
  // currently carefully crafted to avoid races by doing all the JS in one call.
  // That should be fixed before this API goes to stable. See crbug.com/384528
  js_code += "plugin.postMessage('FINISHED_TEST');\n";
  instance_->EvalScript(js_code);
  handler.WaitForTestFinishedMessage();
  handler.Unregister();
  ASSERT_SUBTEST_SUCCESS(handler.WaitForDestroy());

  PASS();
}