/* -*- 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/. */

#if defined(MOZILLA_INTERNAL_API)
#  error This code is NOT for internal Gecko use!
#endif  // defined(MOZILLA_INTERNAL_API)

#include "AccessibleHandlerControl.h"

#include <utility>

#include "AccessibleEventId.h"
#include "AccessibleHandler.h"
#include "mozilla/RefPtr.h"

namespace mozilla {
namespace a11y {

mscom::SingletonFactory<AccessibleHandlerControl> gControlFactory;

namespace detail {

TextChange::TextChange() : mIA2UniqueId(0), mIsInsert(false), mText() {}

TextChange::TextChange(long aIA2UniqueId, bool aIsInsert,
                       NotNull<IA2TextSegment*> aText)
    : mIA2UniqueId(aIA2UniqueId),
      mIsInsert(aIsInsert),
      mText{BSTRCopy(aText->text), aText->start, aText->end} {}

TextChange::TextChange(TextChange&& aOther) : mText() {
  *this = std::move(aOther);
}

TextChange::TextChange(const TextChange& aOther) : mText() { *this = aOther; }

TextChange& TextChange::operator=(TextChange&& aOther) {
  mIA2UniqueId = aOther.mIA2UniqueId;
  mIsInsert = aOther.mIsInsert;
  aOther.mIA2UniqueId = 0;
  ::SysFreeString(mText.text);
  mText = aOther.mText;
  aOther.mText.text = nullptr;
  return *this;
}

TextChange& TextChange::operator=(const TextChange& aOther) {
  mIA2UniqueId = aOther.mIA2UniqueId;
  mIsInsert = aOther.mIsInsert;
  ::SysFreeString(mText.text);
  mText = {BSTRCopy(aOther.mText.text), aOther.mText.start, aOther.mText.end};
  return *this;
}

TextChange::~TextChange() { ::SysFreeString(mText.text); }

HRESULT
TextChange::GetOld(long aIA2UniqueId, NotNull<IA2TextSegment*> aOutOldSegment) {
  if (mIsInsert || aIA2UniqueId != mIA2UniqueId) {
    return S_OK;
  }

  return SegCopy(*aOutOldSegment, mText);
}

HRESULT
TextChange::GetNew(long aIA2UniqueId, NotNull<IA2TextSegment*> aOutNewSegment) {
  if (!mIsInsert || aIA2UniqueId != mIA2UniqueId) {
    return S_OK;
  }

  return SegCopy(*aOutNewSegment, mText);
}

/* static */
BSTR TextChange::BSTRCopy(const BSTR& aIn) {
  return ::SysAllocStringLen(aIn, ::SysStringLen(aIn));
}

/* static */
HRESULT TextChange::SegCopy(IA2TextSegment& aDest, const IA2TextSegment& aSrc) {
  aDest = {BSTRCopy(aSrc.text), aSrc.start, aSrc.end};
  if (aSrc.text && !aDest.text) {
    return E_OUTOFMEMORY;
  }
  if (!::SysStringLen(aDest.text)) {
    return S_FALSE;
  }
  return S_OK;
}

}  // namespace detail

HRESULT
AccessibleHandlerControl::Create(AccessibleHandlerControl** aOutObject) {
  if (!aOutObject) {
    return E_INVALIDARG;
  }

  RefPtr<AccessibleHandlerControl> ctl(new AccessibleHandlerControl());
  ctl.forget(aOutObject);
  return S_OK;
}

AccessibleHandlerControl::AccessibleHandlerControl()
    : mIsRegistered(false),
      mCacheGen(0),
      mIA2Proxy(mscom::RegisterProxy(L"ia2marshal.dll")),
      mHandlerProxy(mscom::RegisterProxy()) {
  MOZ_ASSERT(mIA2Proxy);
}

IMPL_IUNKNOWN1(AccessibleHandlerControl, IHandlerControl)

HRESULT
AccessibleHandlerControl::Invalidate() {
  ++mCacheGen;
  // We can't just call mAccessibleCache.clear() because doing so would release
  // remote objects, making remote COM calls. Since this is an STA, an incoming
  // COM call might be handled which might marshal an AccessibleHandler,
  // which in turn might add itself to mAccessibleCache. Since we'd be in the
  // middle of mutating mAccessibleCache, that might cause a crash. Instead,
  // swap mAccessibleCache into a temporary map first, which will empty
  // mAccessibleCache without releasing remote objects. Once mAccessibleCache
  // is empty, it's safe to let the temporary map be destroyed when it goes
  // out of scope. Remote calls will be made, but nothing will re-enter
  // the temporary map while it's being destroyed.
  AccessibleCache oldCache;
  mAccessibleCache.swap(oldCache);
  return S_OK;
}

HRESULT
AccessibleHandlerControl::OnTextChange(long aHwnd, long aIA2UniqueId,
                                       VARIANT_BOOL aIsInsert,
                                       IA2TextSegment* aText) {
  if (!aText) {
    return E_INVALIDARG;
  }

  mTextChange = detail::TextChange(aIA2UniqueId, aIsInsert, WrapNotNull(aText));
  NotifyWinEvent(aIsInsert ? IA2_EVENT_TEXT_INSERTED : IA2_EVENT_TEXT_REMOVED,
                 reinterpret_cast<HWND>(static_cast<uintptr_t>(aHwnd)),
                 OBJID_CLIENT, aIA2UniqueId);
  return S_OK;
}

HRESULT
AccessibleHandlerControl::GetNewText(long aIA2UniqueId,
                                     NotNull<IA2TextSegment*> aOutNewText) {
  return mTextChange.GetNew(aIA2UniqueId, aOutNewText);
}

HRESULT
AccessibleHandlerControl::GetOldText(long aIA2UniqueId,
                                     NotNull<IA2TextSegment*> aOutOldText) {
  return mTextChange.GetOld(aIA2UniqueId, aOutOldText);
}

HRESULT
AccessibleHandlerControl::GetHandlerTypeInfo(ITypeInfo** aOutTypeInfo) {
  if (!mHandlerProxy) {
    return E_UNEXPECTED;
  }

  return mHandlerProxy->GetTypeInfoForGuid(CLSID_AccessibleHandler,
                                           aOutTypeInfo);
}

HRESULT
AccessibleHandlerControl::Register(NotNull<IGeckoBackChannel*> aGecko) {
  if (mIsRegistered) {
    return S_OK;
  }

  long pid = static_cast<long>(::GetCurrentProcessId());
  HRESULT hr = aGecko->put_HandlerControl(pid, this);
  mIsRegistered = SUCCEEDED(hr);
  MOZ_ASSERT(mIsRegistered);
  return hr;
}

void AccessibleHandlerControl::CacheAccessible(long aUniqueId,
                                               AccessibleHandler* aAccessible) {
  MOZ_ASSERT(aUniqueId && aAccessible);
  mAccessibleCache[aUniqueId] = aAccessible;
}

HRESULT AccessibleHandlerControl::GetCachedAccessible(
    long aUniqueId, AccessibleHandler** aAccessible) {
  MOZ_ASSERT(aUniqueId && aAccessible);
  auto it = mAccessibleCache.find(aUniqueId);
  if (it == mAccessibleCache.end()) {
    return E_INVALIDARG;
  }
  RefPtr<AccessibleHandler> ref = it->second;
  ref.forget(aAccessible);
  return S_OK;
}

}  // namespace a11y
}  // namespace mozilla