#include "base_object-inl.h"
#include "inspector_agent.h"
#include "inspector_io.h"
#include "node_internals.h"
#include "v8.h"
#include "v8-inspector.h"

namespace node {
namespace inspector {
namespace {

using v8::Context;
using v8::Function;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::HandleScope;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::NewStringType;
using v8::Object;
using v8::Persistent;
using v8::String;
using v8::Value;

using v8_inspector::StringBuffer;
using v8_inspector::StringView;

std::unique_ptr<StringBuffer> ToProtocolString(Isolate* isolate,
                                               Local<Value> value) {
  TwoByteValue buffer(isolate, value);
  return StringBuffer::create(StringView(*buffer, buffer.length()));
}

class JSBindingsConnection : public AsyncWrap {
 public:
  class JSBindingsSessionDelegate : public InspectorSessionDelegate {
   public:
    JSBindingsSessionDelegate(Environment* env,
                              JSBindingsConnection* connection)
                              : env_(env),
                                connection_(connection) {
    }

    bool WaitForFrontendMessageWhilePaused() override {
      return false;
    }

    void SendMessageToFrontend(const v8_inspector::StringView& message)
        override {
      Isolate* isolate = env_->isolate();
      HandleScope handle_scope(isolate);
      Context::Scope context_scope(env_->context());
      MaybeLocal<String> v8string =
          String::NewFromTwoByte(isolate, message.characters16(),
                                 NewStringType::kNormal, message.length());
      Local<Value> argument = v8string.ToLocalChecked().As<Value>();
      connection_->OnMessage(argument);
    }

    void Disconnect() {
      Agent* agent = env_->inspector_agent();
      if (agent->delegate() == this)
        agent->Disconnect();
    }

   private:
    Environment* env_;
    JSBindingsConnection* connection_;
  };

  JSBindingsConnection(Environment* env,
                       Local<Object> wrap,
                       Local<Function> callback)
                       : AsyncWrap(env, wrap, PROVIDER_INSPECTORJSBINDING),
                         delegate_(env, this),
                         callback_(env->isolate(), callback) {
    Wrap(wrap, this);

    Agent* inspector = env->inspector_agent();
    if (inspector->delegate() != nullptr) {
      env->ThrowTypeError("Session is already attached");
      return;
    }
    inspector->Connect(&delegate_);
  }

  ~JSBindingsConnection() override {
    callback_.Reset();
  }

  void OnMessage(Local<Value> value) {
    MakeCallback(callback_.Get(env()->isolate()), 1, &value);
  }

  void CheckIsCurrent() {
    Agent* inspector = env()->inspector_agent();
    CHECK_EQ(&delegate_, inspector->delegate());
  }

  static void New(const FunctionCallbackInfo<Value>& info) {
    Environment* env = Environment::GetCurrent(info);
    if (!info[0]->IsFunction()) {
      env->ThrowTypeError("Message callback is required");
      return;
    }
    Local<Function> callback = info[0].As<Function>();
    new JSBindingsConnection(env, info.This(), callback);
  }

  void Disconnect() {
    delegate_.Disconnect();
    if (!persistent().IsEmpty()) {
      ClearWrap(object());
      persistent().Reset();
    }
    delete this;
  }

  static void Disconnect(const FunctionCallbackInfo<Value>& info) {
    JSBindingsConnection* session;
    ASSIGN_OR_RETURN_UNWRAP(&session, info.Holder());
    session->Disconnect();
  }

  static void Dispatch(const FunctionCallbackInfo<Value>& info) {
    Environment* env = Environment::GetCurrent(info);
    JSBindingsConnection* session;
    ASSIGN_OR_RETURN_UNWRAP(&session, info.Holder());
    if (!info[0]->IsString()) {
      env->ThrowTypeError("Inspector message must be a string");
      return;
    }

    session->CheckIsCurrent();
    Agent* inspector = env->inspector_agent();
    inspector->Dispatch(ToProtocolString(env->isolate(), info[0])->string());
  }

  size_t self_size() const override { return sizeof(*this); }

 private:
  JSBindingsSessionDelegate delegate_;
  Persistent<Function> callback_;
};


void AddCommandLineAPI(const FunctionCallbackInfo<Value>& info) {
  auto env = Environment::GetCurrent(info);
  Local<Context> context = env->context();

  if (info.Length() != 2 || !info[0]->IsString()) {
    return env->ThrowTypeError("inspector.addCommandLineAPI takes "
        "exactly 2 arguments: a string and a value.");
  }

  Local<Object> console_api = env->inspector_console_api_object();
  console_api->Set(context, info[0], info[1]).FromJust();
}

void CallAndPauseOnStart(const FunctionCallbackInfo<v8::Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CHECK_GT(args.Length(), 1);
  CHECK(args[0]->IsFunction());
  std::vector<v8::Local<v8::Value>> call_args;
  for (int i = 2; i < args.Length(); i++) {
    call_args.push_back(args[i]);
  }

  env->inspector_agent()->PauseOnNextJavascriptStatement("Break on start");
  v8::MaybeLocal<v8::Value> retval =
      args[0].As<v8::Function>()->Call(env->context(), args[1],
                                       call_args.size(), call_args.data());
  if (!retval.IsEmpty()) {
    args.GetReturnValue().Set(retval.ToLocalChecked());
  }
}

void InspectorConsoleCall(const FunctionCallbackInfo<Value>& info) {
  Isolate* isolate = info.GetIsolate();
  HandleScope handle_scope(isolate);
  Local<Context> context = isolate->GetCurrentContext();
  CHECK_LT(2, info.Length());
  std::vector<Local<Value>> call_args;
  for (int i = 3; i < info.Length(); ++i) {
    call_args.push_back(info[i]);
  }
  Environment* env = Environment::GetCurrent(isolate);
  if (env->inspector_agent()->enabled()) {
    Local<Value> inspector_method = info[0];
    CHECK(inspector_method->IsFunction());
    Local<Value> config_value = info[2];
    CHECK(config_value->IsObject());
    Local<Object> config_object = config_value.As<Object>();
    Local<String> in_call_key = FIXED_ONE_BYTE_STRING(isolate, "in_call");
    if (!config_object->Has(context, in_call_key).FromMaybe(false)) {
      CHECK(config_object->Set(context,
                               in_call_key,
                               v8::True(isolate)).FromJust());
      CHECK(!inspector_method.As<Function>()->Call(context,
                                                   info.Holder(),
                                                   call_args.size(),
                                                   call_args.data()).IsEmpty());
    }
    CHECK(config_object->Delete(context, in_call_key).FromJust());
  }

  Local<Value> node_method = info[1];
  CHECK(node_method->IsFunction());
  node_method.As<Function>()->Call(context,
                                   info.Holder(),
                                   call_args.size(),
                                   call_args.data()).FromMaybe(Local<Value>());
}

static void* GetAsyncTask(int64_t asyncId) {
  // The inspector assumes that when other clients use its asyncTask* API,
  // they use real pointers, or at least something aligned like real pointer.
  // In general it means that our task_id should always be even.
  //
  // On 32bit platforms, the 64bit asyncId would get truncated when converted
  // to a 32bit pointer. However, the javascript part will never enable
  // the async_hook on 32bit platforms, therefore the truncation will never
  // happen in practice.
  return reinterpret_cast<void*>(asyncId << 1);
}

template<void (Agent::*asyncTaskFn)(void*)>
static void InvokeAsyncTaskFnWithId(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CHECK(args[0]->IsNumber());
  int64_t task_id = args[0]->IntegerValue(env->context()).FromJust();
  (env->inspector_agent()->*asyncTaskFn)(GetAsyncTask(task_id));
}

static void AsyncTaskScheduledWrapper(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);

  CHECK(args[0]->IsString());
  Local<String> task_name = args[0].As<String>();
  String::Value task_name_value(task_name);
  StringView task_name_view(*task_name_value, task_name_value.length());

  CHECK(args[1]->IsNumber());
  int64_t task_id = args[1]->IntegerValue(env->context()).FromJust();
  void* task = GetAsyncTask(task_id);

  CHECK(args[2]->IsBoolean());
  bool recurring = args[2]->BooleanValue(env->context()).FromJust();

  env->inspector_agent()->AsyncTaskScheduled(task_name_view, task, recurring);
}

static void RegisterAsyncHookWrapper(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);

  CHECK(args[0]->IsFunction());
  v8::Local<v8::Function> enable_function = args[0].As<Function>();
  CHECK(args[1]->IsFunction());
  v8::Local<v8::Function> disable_function = args[1].As<Function>();
  env->inspector_agent()->RegisterAsyncHook(env->isolate(),
    enable_function, disable_function);
}

void IsEnabled(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  args.GetReturnValue().Set(env->inspector_agent()->enabled());
}

void Open(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  Agent* agent = env->inspector_agent();
  bool wait_for_connect = false;

  if (args.Length() > 0 && args[0]->IsUint32()) {
    uint32_t port = args[0]->Uint32Value();
    agent->options().set_port(static_cast<int>(port));
  }

  if (args.Length() > 1 && args[1]->IsString()) {
    Utf8Value host(env->isolate(), args[1].As<String>());
    agent->options().set_host_name(*host);
  }

  if (args.Length() > 2 && args[2]->IsBoolean()) {
    wait_for_connect = args[2]->BooleanValue(env->context()).FromJust();
  }

  agent->StartIoThread(wait_for_connect);
}

void Url(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  Agent* agent = env->inspector_agent();
  InspectorIo* io = agent->io();

  if (!io) return;

  std::vector<std::string> ids = io->GetTargetIds();

  if (ids.empty()) return;

  std::string url = FormatWsAddress(io->host(), io->port(), ids[0], true);
  args.GetReturnValue().Set(OneByteString(env->isolate(), url.c_str()));
}

void InitInspectorBindings(Local<Object> target, Local<Value> unused,
                           Local<Context> context, void* priv) {
  Environment* env = Environment::GetCurrent(context);
  {
    auto obj = Object::New(env->isolate());
    auto null = Null(env->isolate());
    CHECK(obj->SetPrototype(context, null).FromJust());
    env->set_inspector_console_api_object(obj);
  }

  Agent* agent = env->inspector_agent();
  env->SetMethod(target, "consoleCall", InspectorConsoleCall);
  env->SetMethod(target, "addCommandLineAPI", AddCommandLineAPI);
  if (agent->IsWaitingForConnect())
    env->SetMethod(target, "callAndPauseOnStart", CallAndPauseOnStart);
  env->SetMethod(target, "open", Open);
  env->SetMethod(target, "url", Url);

  env->SetMethod(target, "asyncTaskScheduled", AsyncTaskScheduledWrapper);
  env->SetMethod(target, "asyncTaskCanceled",
      InvokeAsyncTaskFnWithId<&Agent::AsyncTaskCanceled>);
  env->SetMethod(target, "asyncTaskStarted",
      InvokeAsyncTaskFnWithId<&Agent::AsyncTaskStarted>);
  env->SetMethod(target, "asyncTaskFinished",
      InvokeAsyncTaskFnWithId<&Agent::AsyncTaskFinished>);

  env->SetMethod(target, "registerAsyncHook", RegisterAsyncHookWrapper);
  env->SetMethod(target, "isEnabled", IsEnabled);

  auto conn_str = FIXED_ONE_BYTE_STRING(env->isolate(), "Connection");
  Local<FunctionTemplate> tmpl =
      env->NewFunctionTemplate(JSBindingsConnection::New);
  tmpl->InstanceTemplate()->SetInternalFieldCount(1);
  tmpl->SetClassName(conn_str);
  AsyncWrap::AddWrapMethods(env, tmpl);
  env->SetProtoMethod(tmpl, "dispatch", JSBindingsConnection::Dispatch);
  env->SetProtoMethod(tmpl, "disconnect", JSBindingsConnection::Disconnect);
  target->Set(env->context(), conn_str, tmpl->GetFunction()).ToChecked();
}

}  // namespace
}  // namespace inspector
}  // namespace node

NODE_BUILTIN_MODULE_CONTEXT_AWARE(inspector,
                                  node::inspector::InitInspectorBindings);