/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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 "LocalAccessible-inl.h"
#include "AccAttributes.h"
#include "DocAccessibleChild.h"
#include "DocAccessibleWrap.h"
#include "nsIDocShell.h"
#include "nsIScrollableFrame.h"
#include "nsLayoutUtils.h"
#include "nsAccessibilityService.h"
#include "nsAccUtils.h"
#include "Pivot.h"
#include "SessionAccessibility.h"
#include "TraversalRule.h"
#include "mozilla/PresShell.h"
#include "mozilla/a11y/DocAccessiblePlatformExtChild.h"
#include "mozilla/StaticPrefs_accessibility.h"

using namespace mozilla;
using namespace mozilla::a11y;

const uint32_t kCacheRefreshInterval = 500;

#define UNIQUE_ID(acc)                             \
  !acc || (acc->IsDoc() && acc->AsDoc()->IPCDoc()) \
      ? 0                                          \
      : reinterpret_cast<uint64_t>(acc->UniqueID())

////////////////////////////////////////////////////////////////////////////////
// DocAccessibleWrap
////////////////////////////////////////////////////////////////////////////////

DocAccessibleWrap::DocAccessibleWrap(Document* aDocument, PresShell* aPresShell)
    : DocAccessible(aDocument, aPresShell) {
  // We need an nsINode associated with this accessible to register it with the
  // right SessionAccessibility instance. When the base AccessibleWrap
  // constructor is called we don't have one yet because null is passed as the
  // content node. So we do it here after a Document is associated with the
  // accessible.
  if (!IPCAccessibilityActive()) {
    MonitorAutoLock mal(nsAccessibilityService::GetAndroidMonitor());
    SessionAccessibility::RegisterAccessible(this);
  }
}

DocAccessibleWrap::~DocAccessibleWrap() {}

void DocAccessibleWrap::Shutdown() {
  // Unregister here before disconnecting from PresShell.
  if (!IPCAccessibilityActive()) {
    MonitorAutoLock mal(nsAccessibilityService::GetAndroidMonitor());
    if (IsRoot()) {
      SessionAccessibility::UnregisterAll(PresShellPtr());
    } else {
      SessionAccessibility::UnregisterAccessible(this);
    }
  }
  DocAccessible::Shutdown();
}

void DocAccessibleWrap::DoInitialUpdate() {
  DocAccessible::DoInitialUpdate();
  CacheViewport(true);
}

nsresult DocAccessibleWrap::HandleAccEvent(AccEvent* aEvent) {
  switch (aEvent->GetEventType()) {
    case nsIAccessibleEvent::EVENT_SCROLLING_END:
      CacheViewport(false);
      break;
    case nsIAccessibleEvent::EVENT_SCROLLING:
      UpdateFocusPathBounds();
      break;
    default:
      break;
  }

  return DocAccessible::HandleAccEvent(aEvent);
}

void DocAccessibleWrap::CacheViewportCallback(nsITimer* aTimer,
                                              void* aDocAccParam) {
  RefPtr<DocAccessibleWrap> docAcc(
      dont_AddRef(reinterpret_cast<DocAccessibleWrap*>(aDocAccParam)));
  if (!docAcc || docAcc->HasShutdown() ||
      (IPCAccessibilityActive() && !docAcc->IPCDoc())) {
    return;
  }

  PresShell* presShell = docAcc->PresShellPtr();
  nsIFrame* rootFrame = presShell->GetRootFrame();
  if (!rootFrame) {
    return;
  }

  nsTArray<nsIFrame*> frames;
  nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
  nsRect scrollPort = sf ? sf->GetScrollPortRect() : rootFrame->GetRect();

  nsLayoutUtils::GetFramesForArea(
      RelativeTo{presShell->GetRootFrame()}, scrollPort, frames,
      {nsLayoutUtils::FrameForPointOption::OnlyVisible});
  AccessibleHashtable inViewAccs;
  for (size_t i = 0; i < frames.Length(); i++) {
    nsIContent* content = frames.ElementAt(i)->GetContent();
    if (!content) {
      continue;
    }

    LocalAccessible* visibleAcc = docAcc->GetAccessibleOrContainer(content);
    if (!visibleAcc) {
      continue;
    }

    for (LocalAccessible* acc = visibleAcc; acc && acc != docAcc->LocalParent();
         acc = acc->LocalParent()) {
      const bool alreadyPresent =
          inViewAccs.WithEntryHandle(acc->UniqueID(), [&](auto&& entry) {
            if (entry) {
              return true;
            }

            entry.Insert(RefPtr{acc});
            return false;
          });
      if (alreadyPresent) {
        break;
      }
    }
  }

  if (IPCAccessibilityActive()) {
    DocAccessibleChild* ipcDoc = docAcc->IPCDoc();
    nsTArray<BatchData> cacheData(inViewAccs.Count());
    for (auto iter = inViewAccs.Iter(); !iter.Done(); iter.Next()) {
      LocalAccessible* accessible = iter.Data();
      nsAutoString name;
      accessible->Name(name);
      nsAutoString textValue;
      accessible->Value(textValue);
      nsAutoString nodeID;
      accessible->DOMNodeID(nodeID);
      nsAutoString description;
      accessible->Description(description);

      cacheData.AppendElement(BatchData(
          accessible->Document()->IPCDoc(), UNIQUE_ID(accessible),
          accessible->State(), accessible->Bounds(), accessible->ActionCount(),
          name, textValue, nodeID, description, UnspecifiedNaN<double>(),
          UnspecifiedNaN<double>(), UnspecifiedNaN<double>(),
          UnspecifiedNaN<double>(), nullptr));
    }

    ipcDoc->SendBatch(eBatch_Viewport, cacheData);
  } else if (RefPtr<SessionAccessibility> sessionAcc =
                 SessionAccessibility::GetInstanceFor(docAcc)) {
    nsTArray<Accessible*> accessibles(inViewAccs.Count());
    for (const auto& entry : inViewAccs) {
      accessibles.AppendElement(entry.GetWeak());
    }

    sessionAcc->ReplaceViewportCache(accessibles);
  }

  if (docAcc->mCachePivotBoundaries) {
    a11y::Pivot pivot(docAcc);
    TraversalRule rule(java::SessionAccessibility::HTML_GRANULARITY_DEFAULT,
                       true);
    Accessible* maybeFirst = pivot.First(rule);
    Accessible* maybeLast = pivot.Last(rule);
    LocalAccessible* first = maybeFirst ? maybeFirst->AsLocal() : nullptr;
    LocalAccessible* last = maybeLast ? maybeLast->AsLocal() : nullptr;

    // If first/last are null, pass the root document as pivot boundary.
    if (IPCAccessibilityActive()) {
      DocAccessibleChild* ipcDoc = docAcc->IPCDoc();
      DocAccessibleChild* firstDoc =
          first ? first->Document()->IPCDoc() : ipcDoc;
      DocAccessibleChild* lastDoc = last ? last->Document()->IPCDoc() : ipcDoc;
      if (ipcDoc && firstDoc && lastDoc) {
        // One or more of the documents may not have recieved an IPC doc yet.
        // In that case, just throw away this update. We will get a new one soon
        // enough.
        ipcDoc->GetPlatformExtension()->SendSetPivotBoundaries(
            firstDoc, UNIQUE_ID(first), lastDoc, UNIQUE_ID(last));
      }
    } else if (RefPtr<SessionAccessibility> sessionAcc =
                   SessionAccessibility::GetInstanceFor(docAcc)) {
      sessionAcc->UpdateAccessibleFocusBoundaries(
          first ? static_cast<AccessibleWrap*>(first) : docAcc,
          last ? static_cast<AccessibleWrap*>(last) : docAcc);
    }

    docAcc->mCachePivotBoundaries = false;
  }

  if (docAcc->mCacheRefreshTimer) {
    docAcc->mCacheRefreshTimer = nullptr;
  }
}

void DocAccessibleWrap::CacheViewport(bool aCachePivotBoundaries) {
  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
    return;
  }
  mCachePivotBoundaries |= aCachePivotBoundaries;
  if (IsTopLevelContentDoc() && !mCacheRefreshTimer) {
    NS_NewTimerWithFuncCallback(getter_AddRefs(mCacheRefreshTimer),
                                CacheViewportCallback, this,
                                kCacheRefreshInterval, nsITimer::TYPE_ONE_SHOT,
                                "a11y::DocAccessibleWrap::CacheViewport");
    if (mCacheRefreshTimer) {
      NS_ADDREF_THIS();  // Kung fu death grip
    }
  }
}

DocAccessibleWrap* DocAccessibleWrap::GetTopLevelContentDoc(
    AccessibleWrap* aAccessible) {
  DocAccessibleWrap* doc =
      static_cast<DocAccessibleWrap*>(aAccessible->Document());
  while (doc && !doc->IsTopLevelContentDoc()) {
    doc = static_cast<DocAccessibleWrap*>(doc->ParentDocument());
  }

  return doc;
}

bool DocAccessibleWrap::IsTopLevelContentDoc() {
  DocAccessible* parentDoc = ParentDocument();
  return DocumentNode()->IsContentDocument() &&
         (!parentDoc || !parentDoc->DocumentNode()->IsContentDocument());
}

void DocAccessibleWrap::CacheFocusPath(AccessibleWrap* aAccessible) {
  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
    return;
  }

  mFocusPath.Clear();
  if (IPCAccessibilityActive()) {
    DocAccessibleChild* ipcDoc = IPCDoc();
    nsTArray<BatchData> cacheData;
    for (AccessibleWrap* acc = aAccessible; acc && acc != this->LocalParent();
         acc = static_cast<AccessibleWrap*>(acc->LocalParent())) {
      nsAutoString name;
      acc->Name(name);
      nsAutoString textValue;
      acc->Value(textValue);
      nsAutoString nodeID;
      acc->DOMNodeID(nodeID);
      nsAutoString description;
      acc->Description(description);
      RefPtr<AccAttributes> attributes = acc->Attributes();
      cacheData.AppendElement(
          BatchData(acc->Document()->IPCDoc(), UNIQUE_ID(acc), acc->State(),
                    acc->Bounds(), acc->ActionCount(), name, textValue, nodeID,
                    description, acc->CurValue(), acc->MinValue(),
                    acc->MaxValue(), acc->Step(), attributes));
      mFocusPath.InsertOrUpdate(acc->UniqueID(), RefPtr{acc});
    }

    ipcDoc->SendBatch(eBatch_FocusPath, cacheData);
  } else if (RefPtr<SessionAccessibility> sessionAcc =
                 SessionAccessibility::GetInstanceFor(this)) {
    nsTArray<Accessible*> accessibles;
    for (LocalAccessible* acc = aAccessible; acc && acc != this->LocalParent();
         acc = acc->LocalParent()) {
      accessibles.AppendElement(acc);
      mFocusPath.InsertOrUpdate(acc->UniqueID(), RefPtr{acc});
    }

    sessionAcc->ReplaceFocusPathCache(accessibles);
  }
}

void DocAccessibleWrap::UpdateFocusPathBounds() {
  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
    return;
  }

  if (!mFocusPath.Count()) {
    return;
  }

  if (IPCAccessibilityActive()) {
    DocAccessibleChild* ipcDoc = IPCDoc();
    nsTArray<BatchData> boundsData(mFocusPath.Count());
    for (auto iter = mFocusPath.Iter(); !iter.Done(); iter.Next()) {
      LocalAccessible* accessible = iter.Data();
      if (!accessible || accessible->IsDefunct()) {
        MOZ_ASSERT_UNREACHABLE("Focus path cached accessible is gone.");
        continue;
      }

      boundsData.AppendElement(BatchData(
          accessible->Document()->IPCDoc(), UNIQUE_ID(accessible), 0,
          accessible->Bounds(), 0, nsString(), nsString(), nsString(),
          nsString(), UnspecifiedNaN<double>(), UnspecifiedNaN<double>(),
          UnspecifiedNaN<double>(), UnspecifiedNaN<double>(), nullptr));
    }

    ipcDoc->SendBatch(eBatch_BoundsUpdate, boundsData);
  } else if (RefPtr<SessionAccessibility> sessionAcc =
                 SessionAccessibility::GetInstanceFor(this)) {
    nsTArray<Accessible*> accessibles(mFocusPath.Count());
    for (auto iter = mFocusPath.Iter(); !iter.Done(); iter.Next()) {
      LocalAccessible* accessible = iter.Data();
      if (!accessible || accessible->IsDefunct()) {
        MOZ_ASSERT_UNREACHABLE("Focus path cached accessible is gone.");
        continue;
      }

      accessibles.AppendElement(accessible);
    }

    sessionAcc->UpdateCachedBounds(accessibles);
  }
}

#undef UNIQUE_ID