/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/telemetry/Stopwatch.h"

#include "TelemetryHistogram.h"

#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/TimeStamp.h"
#include "nsHashKeys.h"
#include "nsContentUtils.h"
#include "nsPrintfCString.h"
#include "nsQueryObject.h"
#include "nsRefPtrHashtable.h"
#include "nsString.h"
#include "xpcpublic.h"

using mozilla::dom::AutoJSAPI;

static inline nsQueryObject<nsISupports> do_QueryReflector(
    JSObject* aReflector) {
  // None of the types we query to are implemented by Window or Location.
  nsCOMPtr<nsISupports> reflector = xpc::ReflectorToISupportsStatic(aReflector);
  return do_QueryObject(reflector);
}

static inline nsQueryObject<nsISupports> do_QueryReflector(
    const JS::Value& aReflector) {
  return do_QueryReflector(&aReflector.toObject());
}

static void LogError(JSContext* aCx, const nsCString& aMessage) {
  // This is a bit of a hack to report an error with the current JS caller's
  // location. We create an AutoJSAPI object bound to the current caller
  // global, report a JS error, and then let AutoJSAPI's destructor report the
  // error.
  //
  // Unfortunately, there isn't currently a more straightforward way to do
  // this from C++.
  JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx));

  AutoJSAPI jsapi;
  if (jsapi.Init(global)) {
    JS_ReportErrorUTF8(jsapi.cx(), "%s", aMessage.get());
  }
}

namespace mozilla::telemetry {

class Timer final {
 public:
  NS_INLINE_DECL_REFCOUNTING(Timer)

  Timer() = default;

  void Start(bool aInSeconds) {
    mStartTime = TimeStamp::Now();
    mInSeconds = aInSeconds;
  }

  bool Started() { return !mStartTime.IsNull(); }

  uint32_t Elapsed() {
    auto delta = TimeStamp::Now() - mStartTime;
    return mInSeconds ? delta.ToSeconds() : delta.ToMilliseconds();
  }

  bool& InSeconds() { return mInSeconds; }

 private:
  ~Timer() = default;

  TimeStamp mStartTime{};
  bool mInSeconds;
};

#define TIMER_KEYS_IID                               \
  {                                                  \
    0xef707178, 0x1544, 0x46e2, {                    \
      0xa3, 0xf5, 0x98, 0x38, 0xba, 0x60, 0xfd, 0x8f \
    }                                                \
  }

class TimerKeys final : public nsISupports {
 public:
  NS_DECL_ISUPPORTS
  NS_DECLARE_STATIC_IID_ACCESSOR(TIMER_KEYS_IID)

  Timer* Get(const nsAString& aKey, bool aCreate = true);

  already_AddRefed<Timer> GetAndDelete(const nsAString& aKey) {
    RefPtr<Timer> timer;
    mTimers.Remove(aKey, getter_AddRefs(timer));
    return timer.forget();
  }

  bool Delete(const nsAString& aKey) { return mTimers.Remove(aKey); }

 private:
  ~TimerKeys() = default;

  nsRefPtrHashtable<nsStringHashKey, Timer> mTimers;
};

NS_DEFINE_STATIC_IID_ACCESSOR(TimerKeys, TIMER_KEYS_IID)

NS_IMPL_ISUPPORTS(TimerKeys, TimerKeys)

Timer* TimerKeys::Get(const nsAString& aKey, bool aCreate) {
  if (aCreate) {
    RefPtr<Timer>& timer = mTimers.GetOrInsert(aKey);
    if (!timer) {
      timer = new Timer();
    }
    return timer;
  }
  return mTimers.GetWeak(aKey);
}

class Timers final {
 public:
  Timers();

  static Timers& Singleton();

  NS_INLINE_DECL_REFCOUNTING(Timers)

  JSObject* Get(JSContext* aCx, const nsAString& aHistogram,
                bool aCreate = true);

  TimerKeys* Get(JSContext* aCx, const nsAString& aHistogram,
                 JS::HandleObject aObj, bool aCreate = true);

  Timer* Get(JSContext* aCx, const nsAString& aHistogram, JS::HandleObject aObj,
             const nsAString& aKey, bool aCreate = true);

  already_AddRefed<Timer> GetAndDelete(JSContext* aCx,
                                       const nsAString& aHistogram,
                                       JS::HandleObject aObj,
                                       const nsAString& aKey);

  bool Delete(JSContext* aCx, const nsAString& aHistogram,
              JS::HandleObject aObj, const nsAString& aKey);

  int32_t TimeElapsed(JSContext* aCx, const nsAString& aHistogram,
                      JS::HandleObject aObj, const nsAString& aKey,
                      bool aCanceledOkay = false, bool aDelete = false);

  bool Start(JSContext* aCx, const nsAString& aHistogram, JS::HandleObject aObj,
             const nsAString& aKey, bool aInSeconds = false);

  int32_t Finish(JSContext* aCx, const nsAString& aHistogram,
                 JS::HandleObject aObj, const nsAString& aKey,
                 bool aCanceledOkay = false);

  bool& SuppressErrors() { return mSuppressErrors; }

 private:
  ~Timers() = default;

  JS::PersistentRooted<JSObject*> mTimers;
  bool mSuppressErrors = false;

  static StaticRefPtr<Timers> sSingleton;
};

StaticRefPtr<Timers> Timers::sSingleton;

/* static */ Timers& Timers::Singleton() {
  if (!sSingleton) {
    sSingleton = new Timers();
    ClearOnShutdown(&sSingleton);
  }
  return *sSingleton;
}

Timers::Timers() : mTimers(dom::RootingCx()) {
  AutoJSAPI jsapi;
  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));

  mTimers = JS::NewMapObject(jsapi.cx());
  MOZ_RELEASE_ASSERT(mTimers);
}

JSObject* Timers::Get(JSContext* aCx, const nsAString& aHistogram,
                      bool aCreate) {
  JSAutoRealm ar(aCx, mTimers);

  JS::RootedValue histogram(aCx);
  JS::RootedValue objs(aCx);

  if (!xpc::NonVoidStringToJsval(aCx, aHistogram, &histogram) ||
      !JS::MapGet(aCx, mTimers, histogram, &objs)) {
    return nullptr;
  }
  if (!objs.isObject()) {
    if (aCreate) {
      objs = JS::ObjectOrNullValue(JS::NewWeakMapObject(aCx));
    }
    if (!objs.isObject() || !JS::MapSet(aCx, mTimers, histogram, objs)) {
      return nullptr;
    }
  }

  return &objs.toObject();
}

TimerKeys* Timers::Get(JSContext* aCx, const nsAString& aHistogram,
                       JS::HandleObject aObj, bool aCreate) {
  JSAutoRealm ar(aCx, mTimers);

  JS::RootedObject objs(aCx, Get(aCx, aHistogram, aCreate));
  if (!objs) {
    return nullptr;
  }

  // If no object is passed, use mTimers as a stand-in for a null object
  // (which cannot be used as a weak map key).
  JS::RootedObject obj(aCx, aObj ? aObj : mTimers);
  if (!JS_WrapObject(aCx, &obj)) {
    return nullptr;
  }

  RefPtr<TimerKeys> keys;
  JS::RootedValue keysObj(aCx);
  if (!JS::GetWeakMapEntry(aCx, objs, obj, &keysObj)) {
    return nullptr;
  }
  if (!keysObj.isObject()) {
    if (aCreate) {
      keys = new TimerKeys();
      Unused << nsContentUtils::WrapNative(aCx, keys, &keysObj);
    }
    if (!keysObj.isObject() || !JS::SetWeakMapEntry(aCx, objs, obj, keysObj)) {
      return nullptr;
    }
  }

  keys = do_QueryReflector(keysObj);
  return keys;
}

Timer* Timers::Get(JSContext* aCx, const nsAString& aHistogram,
                   JS::HandleObject aObj, const nsAString& aKey, bool aCreate) {
  if (RefPtr<TimerKeys> keys = Get(aCx, aHistogram, aObj, aCreate)) {
    return keys->Get(aKey, aCreate);
  }
  return nullptr;
}

already_AddRefed<Timer> Timers::GetAndDelete(JSContext* aCx,
                                             const nsAString& aHistogram,
                                             JS::HandleObject aObj,
                                             const nsAString& aKey) {
  if (RefPtr<TimerKeys> keys = Get(aCx, aHistogram, aObj, false)) {
    return keys->GetAndDelete(aKey);
  }
  return nullptr;
}

bool Timers::Delete(JSContext* aCx, const nsAString& aHistogram,
                    JS::HandleObject aObj, const nsAString& aKey) {
  if (RefPtr<TimerKeys> keys = Get(aCx, aHistogram, aObj, false)) {
    return keys->Delete(aKey);
  }
  return false;
}

int32_t Timers::TimeElapsed(JSContext* aCx, const nsAString& aHistogram,
                            JS::HandleObject aObj, const nsAString& aKey,
                            bool aCanceledOkay, bool aDelete) {
  RefPtr<Timer> timer;
  if (aDelete) {
    timer = GetAndDelete(aCx, aHistogram, aObj, aKey);
  } else {
    timer = Get(aCx, aHistogram, aObj, aKey, false);
  }
  if (!timer) {
    if (!aCanceledOkay && !mSuppressErrors) {
      LogError(aCx, nsPrintfCString(
                        "TelemetryStopwatch: requesting elapsed time for "
                        "nonexisting stopwatch. Histogram: \"%s\", key: \"%s\"",
                        NS_ConvertUTF16toUTF8(aHistogram).get(),
                        NS_ConvertUTF16toUTF8(aKey).get()));
    }
    return -1;
  }

  return timer->Elapsed();
}

bool Timers::Start(JSContext* aCx, const nsAString& aHistogram,
                   JS::HandleObject aObj, const nsAString& aKey,
                   bool aInSeconds) {
  if (RefPtr<Timer> timer = Get(aCx, aHistogram, aObj, aKey)) {
    if (timer->Started()) {
      if (!mSuppressErrors) {
        LogError(aCx,
                 nsPrintfCString(
                     "TelemetryStopwatch: key \"%s\" was already initialized",
                     NS_ConvertUTF16toUTF8(aHistogram).get()));
      }
      Delete(aCx, aHistogram, aObj, aKey);
    } else {
      timer->Start(aInSeconds);
      return true;
    }
  }
  return false;
}

int32_t Timers::Finish(JSContext* aCx, const nsAString& aHistogram,
                       JS::HandleObject aObj, const nsAString& aKey,
                       bool aCanceledOkay) {
  int32_t delta = TimeElapsed(aCx, aHistogram, aObj, aKey, aCanceledOkay, true);
  if (delta == -1) {
    return delta;
  }

  NS_ConvertUTF16toUTF8 histogram(aHistogram);
  nsresult rv;
  if (!aKey.IsVoid()) {
    NS_ConvertUTF16toUTF8 key(aKey);
    rv = TelemetryHistogram::Accumulate(histogram.get(), key, delta);
  } else {
    rv = TelemetryHistogram::Accumulate(histogram.get(), delta);
  }
  if (NS_FAILED(rv) && rv != NS_ERROR_NOT_AVAILABLE && !mSuppressErrors) {
    LogError(aCx, nsPrintfCString(
                      "TelemetryStopwatch: failed to update the Histogram "
                      "\"%s\", using key: \"%s\"",
                      NS_ConvertUTF16toUTF8(aHistogram).get(),
                      NS_ConvertUTF16toUTF8(aKey).get()));
  }
  return NS_SUCCEEDED(rv) ? delta : -1;
}

/* static */
bool Stopwatch::Start(const dom::GlobalObject& aGlobal,
                      const nsAString& aHistogram, JS::Handle<JSObject*> aObj,
                      const dom::TelemetryStopwatchOptions& aOptions) {
  return StartKeyed(aGlobal, aHistogram, VoidString(), aObj, aOptions);
}
/* static */
bool Stopwatch::StartKeyed(const dom::GlobalObject& aGlobal,
                           const nsAString& aHistogram, const nsAString& aKey,
                           JS::Handle<JSObject*> aObj,
                           const dom::TelemetryStopwatchOptions& aOptions) {
  return Timers::Singleton().Start(aGlobal.Context(), aHistogram, aObj, aKey,
                                   aOptions.mInSeconds);
}

/* static */
bool Stopwatch::Running(const dom::GlobalObject& aGlobal,
                        const nsAString& aHistogram,
                        JS::Handle<JSObject*> aObj) {
  return RunningKeyed(aGlobal, aHistogram, VoidString(), aObj);
}

/* static */
bool Stopwatch::RunningKeyed(const dom::GlobalObject& aGlobal,
                             const nsAString& aHistogram, const nsAString& aKey,
                             JS::Handle<JSObject*> aObj) {
  return TimeElapsedKeyed(aGlobal, aHistogram, aKey, aObj, true) != -1;
}

/* static */
int32_t Stopwatch::TimeElapsed(const dom::GlobalObject& aGlobal,
                               const nsAString& aHistogram,
                               JS::Handle<JSObject*> aObj, bool aCanceledOkay) {
  return TimeElapsedKeyed(aGlobal, aHistogram, VoidString(), aObj,
                          aCanceledOkay);
}

/* static */
int32_t Stopwatch::TimeElapsedKeyed(const dom::GlobalObject& aGlobal,
                                    const nsAString& aHistogram,
                                    const nsAString& aKey,
                                    JS::Handle<JSObject*> aObj,
                                    bool aCanceledOkay) {
  return Timers::Singleton().TimeElapsed(aGlobal.Context(), aHistogram, aObj,
                                         aKey, aCanceledOkay);
}

/* static */
bool Stopwatch::Finish(const dom::GlobalObject& aGlobal,
                       const nsAString& aHistogram, JS::Handle<JSObject*> aObj,
                       bool aCanceledOkay) {
  return FinishKeyed(aGlobal, aHistogram, VoidString(), aObj, aCanceledOkay);
}

/* static */
bool Stopwatch::FinishKeyed(const dom::GlobalObject& aGlobal,
                            const nsAString& aHistogram, const nsAString& aKey,
                            JS::Handle<JSObject*> aObj, bool aCanceledOkay) {
  return Timers::Singleton().Finish(aGlobal.Context(), aHistogram, aObj, aKey,
                                    aCanceledOkay) != -1;
}

/* static */
bool Stopwatch::Cancel(const dom::GlobalObject& aGlobal,
                       const nsAString& aHistogram,
                       JS::Handle<JSObject*> aObj) {
  return CancelKeyed(aGlobal, aHistogram, VoidString(), aObj);
}

/* static */
bool Stopwatch::CancelKeyed(const dom::GlobalObject& aGlobal,
                            const nsAString& aHistogram, const nsAString& aKey,
                            JS::Handle<JSObject*> aObj) {
  return Timers::Singleton().Delete(aGlobal.Context(), aHistogram, aObj, aKey);
}

/* static */
void Stopwatch::SetTestModeEnabled(const dom::GlobalObject& aGlobal,
                                   bool aTesting) {
  Timers::Singleton().SuppressErrors() = aTesting;
}

}  // namespace mozilla::telemetry