/* 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/. */

#ifndef Helpers_h
#define Helpers_h

#include "nsCOMPtr.h"
#include "nsIAsyncInputStream.h"
#include "nsIAsyncOutputStream.h"
#include "nsIInputStreamLength.h"
#include "nsString.h"
#include "nsStringStream.h"
#include "nsTArrayForwardDeclare.h"
#include "nsThreadUtils.h"
#include "mozilla/Queue.h"
#include <stdint.h>

class nsIInputStream;
class nsIOutputStream;

namespace testing {

void CreateData(uint32_t aNumBytes, nsTArray<char>& aDataOut);

void Write(nsIOutputStream* aStream, const nsTArray<char>& aData,
           uint32_t aOffset, uint32_t aNumBytes);

void WriteAllAndClose(nsIOutputStream* aStream, const nsTArray<char>& aData);

void ConsumeAndValidateStream(nsIInputStream* aStream,
                              const nsTArray<char>& aExpectedData);

void ConsumeAndValidateStream(nsIInputStream* aStream,
                              const nsACString& aExpectedData);

class OutputStreamCallback final : public nsIOutputStreamCallback {
 public:
  OutputStreamCallback();

  bool Called() const { return mCalled; }

 private:
  ~OutputStreamCallback();

  bool mCalled;

 public:
  NS_DECL_ISUPPORTS
  NS_DECL_NSIOUTPUTSTREAMCALLBACK
};

class InputStreamCallback final : public nsIInputStreamCallback {
 public:
  InputStreamCallback();

  bool Called() const { return mCalled; }

 private:
  ~InputStreamCallback();

  bool mCalled;

 public:
  NS_DECL_ISUPPORTS
  NS_DECL_NSIINPUTSTREAMCALLBACK
};

class AsyncStringStream final : public nsIAsyncInputStream {
  nsCOMPtr<nsIInputStream> mStream;

 public:
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIINPUTSTREAM
  NS_DECL_NSIASYNCINPUTSTREAM

  explicit AsyncStringStream(const nsACString& aBuffer);

 private:
  ~AsyncStringStream() = default;

  void MaybeExecCallback(nsIInputStreamCallback* aCallback,
                         nsIEventTarget* aEventTarget);

  nsCOMPtr<nsIInputStreamCallback> mCallback;
  nsCOMPtr<nsIEventTarget> mCallbackEventTarget;
};

// This class implements a simple nsIInputStreamLength stream.
class LengthInputStream : public nsIInputStream,
                          public nsIInputStreamLength,
                          public nsIAsyncInputStreamLength {
  nsCOMPtr<nsIInputStream> mStream;
  bool mIsInputStreamLength;
  bool mIsAsyncInputStreamLength;
  nsresult mLengthRv;
  bool mNegativeValue;

 public:
  NS_DECL_THREADSAFE_ISUPPORTS

  LengthInputStream(const nsACString& aBuffer, bool aIsInputStreamLength,
                    bool aIsAsyncInputStreamLength, nsresult aLengthRv = NS_OK,
                    bool aNegativeValue = false)
      : mIsInputStreamLength(aIsInputStreamLength),
        mIsAsyncInputStreamLength(aIsAsyncInputStreamLength),
        mLengthRv(aLengthRv),
        mNegativeValue(aNegativeValue) {
    NS_NewCStringInputStream(getter_AddRefs(mStream), aBuffer);
  }

  NS_IMETHOD
  Available(uint64_t* aLength) override { return mStream->Available(aLength); }

  NS_IMETHOD
  StreamStatus() override { return mStream->StreamStatus(); }

  NS_IMETHOD
  Read(char* aBuffer, uint32_t aCount, uint32_t* aReadCount) override {
    return mStream->Read(aBuffer, aCount, aReadCount);
  }

  NS_IMETHOD
  ReadSegments(nsWriteSegmentFun aWriter, void* aClosure, uint32_t aCount,
               uint32_t* aResult) override {
    return mStream->ReadSegments(aWriter, aClosure, aCount, aResult);
  }

  NS_IMETHOD
  Close() override { return mStream->Close(); }

  NS_IMETHOD
  IsNonBlocking(bool* aNonBlocking) override {
    return mStream->IsNonBlocking(aNonBlocking);
  }

  NS_IMETHOD
  Length(int64_t* aLength) override {
    if (mNegativeValue) {
      *aLength = -1;
    } else {
      mStream->Available((uint64_t*)aLength);
    }
    return mLengthRv;
  }

  NS_IMETHOD
  AsyncLengthWait(nsIInputStreamLengthCallback* aCallback,
                  nsIEventTarget* aEventTarget) override {
    RefPtr<LengthInputStream> self = this;
    nsCOMPtr<nsIInputStreamLengthCallback> callback = aCallback;

    nsCOMPtr<nsIRunnable> r =
        NS_NewRunnableFunction("AsyncLengthWait", [self, callback]() {
          int64_t length;
          self->Length(&length);
          callback->OnInputStreamLengthReady(self, length);
        });

    return aEventTarget->Dispatch(r.forget(), NS_DISPATCH_NORMAL);
  }

 protected:
  virtual ~LengthInputStream() = default;
};

class LengthCallback final : public nsIInputStreamLengthCallback {
  bool mCalled;
  int64_t mSize;

 public:
  NS_DECL_THREADSAFE_ISUPPORTS

  LengthCallback() : mCalled(false), mSize(0) {}

  NS_IMETHOD
  OnInputStreamLengthReady(nsIAsyncInputStreamLength* aStream,
                           int64_t aLength) override {
    mCalled = true;
    mSize = aLength;
    return NS_OK;
  }

  bool Called() const { return mCalled; }

  int64_t Size() const { return mSize; }

 private:
  ~LengthCallback() = default;
};

// A simple queue of runnables, to serve as the base target of
// ThrottledEventQueues/StopGapEventTargets (or other event targets that are
// some kind of passthrough/filter) in tests.
//
// This is much simpler than mozilla::TaskQueue, and so better for unit tests.
// It's about the same as mozilla::EventQueue, but that doesn't implement
// nsIEventTarget, so it can't be the base target of a ThrottledEventQueue or
// StopGapEventTarget.
struct RunnableQueue : public nsISerialEventTarget {
  mozilla::Queue<nsCOMPtr<nsIRunnable>> runnables;

  bool IsEmpty() { return runnables.IsEmpty(); }
  size_t Length() { return runnables.Count(); }

  [[nodiscard]] nsresult Run() {
    while (!runnables.IsEmpty()) {
      auto runnable = runnables.Pop();
      nsresult rv = runnable->Run();
      if (NS_FAILED(rv)) return rv;
    }

    return NS_OK;
  }

  // nsIEventTarget methods

  [[nodiscard]] NS_IMETHODIMP Dispatch(already_AddRefed<nsIRunnable> aRunnable,
                                       DispatchFlags aFlags) override {
    MOZ_ALWAYS_TRUE(aFlags == nsIEventTarget::DISPATCH_NORMAL);
    runnables.Push(aRunnable);
    return NS_OK;
  }

  [[nodiscard]] NS_IMETHODIMP DispatchFromScript(
      nsIRunnable* aRunnable, DispatchFlags aFlags) override {
    RefPtr<nsIRunnable> r = aRunnable;
    return Dispatch(r.forget(), aFlags);
  }

  NS_IMETHOD_(bool)
  IsOnCurrentThreadInfallible(void) override { return NS_IsMainThread(); }

  [[nodiscard]] NS_IMETHOD IsOnCurrentThread(bool* retval) override {
    *retval = IsOnCurrentThreadInfallible();
    return NS_OK;
  }

  [[nodiscard]] NS_IMETHODIMP DelayedDispatch(
      already_AddRefed<nsIRunnable> aEvent, uint32_t aDelay) override {
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  NS_IMETHOD RegisterShutdownTask(nsITargetShutdownTask*) override {
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  NS_IMETHOD UnregisterShutdownTask(nsITargetShutdownTask*) override {
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  NS_IMETHOD_(FeatureFlags) GetFeatures() override { return SUPPORTS_BASE; }

  // nsISupports methods

  NS_DECL_THREADSAFE_ISUPPORTS

 private:
  virtual ~RunnableQueue() = default;
};

}  // namespace testing

#endif  // Helpers_h