/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 mozilla_a11y_DocAccessibleChild_h
#define mozilla_a11y_DocAccessibleChild_h

#include "mozilla/a11y/COMPtrTypes.h"
#include "mozilla/a11y/DocAccessibleChildBase.h"
#include "mozilla/dom/TabChild.h"
#include "mozilla/mscom/Ptr.h"

namespace mozilla {
namespace a11y {

/*
 * These objects handle content side communication for an accessible document,
 * and their lifetime is the same as the document they represent.
 */
class DocAccessibleChild : public DocAccessibleChildBase
{
public:
  explicit DocAccessibleChild(DocAccessible* aDoc);
  ~DocAccessibleChild();

  virtual void Shutdown() override;

  virtual bool
  RecvParentCOMProxy(const IAccessibleHolder& aParentCOMProxy) override;

  IAccessible* GetParentIAccessible() const { return mParentProxy.get(); }

  bool SendEvent(const uint64_t& aID, const uint32_t& type);
  bool SendHideEvent(const uint64_t& aRootID, const bool& aFromUser);
  bool SendStateChangeEvent(const uint64_t& aID, const uint64_t& aState,
                            const bool& aEnabled);
  bool SendCaretMoveEvent(const uint64_t& aID, const int32_t& aOffset);
  bool SendTextChangeEvent(const uint64_t& aID, const nsString& aStr,
                           const int32_t& aStart, const uint32_t& aLen,
                           const bool& aIsInsert, const bool& aFromUser);
  bool SendSelectionEvent(const uint64_t& aID, const uint64_t& aWidgetID,
                          const uint32_t& aType);
  bool SendRoleChangedEvent(const uint32_t& aRole);

  bool ConstructChildDocInParentProcess(DocAccessibleChild* aNewChildDoc,
                                        uint64_t aUniqueID, uint32_t aMsaaID);

  bool SendBindChildDoc(DocAccessibleChild* aChildDoc,
                        const uint64_t& aNewParentID);

protected:
  virtual void MaybeSendShowEvent(ShowEventData& aData, bool aFromUser) override;

private:
  void RemoveDeferredConstructor();

  bool IsConstructedInParentProcess() const { return mIsRemoteConstructed; }
  void SetConstructedInParentProcess() { mIsRemoteConstructed = true; }

  /**
   * DocAccessibleChild should not fire events until it has asynchronously
   * received the COM proxy for its parent. OTOH, content a11y may still be
   * attempting to fire events during this window of time. If this object does
   * not yet have its parent proxy, instead of immediately sending the events to
   * our parent, we enqueue them to mDeferredEvents. As soon as
   * RecvParentCOMProxy is called, we play back mDeferredEvents.
   */
  struct DeferredEvent
  {
    void Dispatch()
    {
      Dispatch(mTarget);
    }

    virtual ~DeferredEvent() {}

  protected:
    explicit DeferredEvent(DocAccessibleChild* aTarget)
      : mTarget(aTarget)
    {}

    virtual void Dispatch(DocAccessibleChild* aIPCDoc) = 0;

  private:
    DocAccessibleChild* mTarget;
  };

  void PushDeferredEvent(UniquePtr<DeferredEvent> aEvent);

  struct SerializedShow final : public DeferredEvent
  {
    SerializedShow(DocAccessibleChild* aTarget,
                   ShowEventData& aEventData, bool aFromUser)
      : DeferredEvent(aTarget)
      , mEventData(aEventData.ID(), aEventData.Idx(), nsTArray<AccessibleData>())
      , mFromUser(aFromUser)
    {
      // Since IPDL doesn't generate a move constructor for ShowEventData,
      // we move NewTree manually (ugh). We still construct with an empty
      // NewTree above so that the compiler catches any changes made to the
      // ShowEventData structure in IPDL.
      mEventData.NewTree() = Move(aEventData.NewTree());
    }

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendShowEvent(mEventData, mFromUser);
    }

    ShowEventData mEventData;
    bool          mFromUser;
  };

  struct SerializedHide final : public DeferredEvent
  {
    SerializedHide(DocAccessibleChild* aTarget, uint64_t aRootID, bool aFromUser)
      : DeferredEvent(aTarget)
      , mRootID(aRootID)
      , mFromUser(aFromUser)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendHideEvent(mRootID, mFromUser);
    }

    uint64_t  mRootID;
    bool      mFromUser;
  };

  struct SerializedStateChange final : public DeferredEvent
  {
    SerializedStateChange(DocAccessibleChild* aTarget, uint64_t aID,
                          uint64_t aState, bool aEnabled)
      : DeferredEvent(aTarget)
      , mID(aID)
      , mState(aState)
      , mEnabled(aEnabled)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendStateChangeEvent(mID, mState, mEnabled);
    }

    uint64_t  mID;
    uint64_t  mState;
    bool      mEnabled;
  };

  struct SerializedCaretMove final : public DeferredEvent
  {
    SerializedCaretMove(DocAccessibleChild* aTarget, uint64_t aID,
                        int32_t aOffset)
      : DeferredEvent(aTarget)
      , mID(aID)
      , mOffset(aOffset)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendCaretMoveEvent(mID, mOffset);
    }

    uint64_t  mID;
    int32_t   mOffset;
  };

  struct SerializedTextChange final : public DeferredEvent
  {
    SerializedTextChange(DocAccessibleChild* aTarget, uint64_t aID,
                         const nsString& aStr, int32_t aStart, uint32_t aLen,
                         bool aIsInsert, bool aFromUser)
      : DeferredEvent(aTarget)
      , mID(aID)
      , mStr(aStr)
      , mStart(aStart)
      , mLen(aLen)
      , mIsInsert(aIsInsert)
      , mFromUser(aFromUser)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendTextChangeEvent(mID, mStr, mStart, mLen, mIsInsert,
                                             mFromUser);
    }

    uint64_t  mID;
    nsString  mStr;
    int32_t   mStart;
    uint32_t  mLen;
    bool      mIsInsert;
    bool      mFromUser;
  };

  struct SerializedSelection final : public DeferredEvent
  {
    SerializedSelection(DocAccessibleChild* aTarget, uint64_t aID,
                        uint64_t aWidgetID, uint32_t aType)
      : DeferredEvent(aTarget)
      , mID(aID)
      , mWidgetID(aWidgetID)
      , mType(aType)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendSelectionEvent(mID, mWidgetID, mType);
    }

    uint64_t  mID;
    uint64_t  mWidgetID;
    uint32_t  mType;
  };

  struct SerializedRoleChanged final : public DeferredEvent
  {
    explicit SerializedRoleChanged(DocAccessibleChild* aTarget, uint32_t aRole)
      : DeferredEvent(aTarget)
      , mRole(aRole)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendRoleChangedEvent(mRole);
    }

    uint32_t mRole;
  };

  struct SerializedEvent final : public DeferredEvent
  {
    SerializedEvent(DocAccessibleChild* aTarget, uint64_t aID, uint32_t aType)
      : DeferredEvent(aTarget)
      , mID(aID)
      , mType(aType)
    {}

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      Unused << aIPCDoc->SendEvent(mID, mType);
    }

    uint64_t  mID;
    uint32_t  mType;
  };

  struct SerializedChildDocConstructor final : public DeferredEvent
  {
    SerializedChildDocConstructor(DocAccessibleChild* aIPCDoc,
                                  DocAccessibleChild* aParentIPCDoc,
                                  uint64_t aUniqueID, uint32_t aMsaaID)
      : DeferredEvent(aParentIPCDoc)
      , mIPCDoc(aIPCDoc)
      , mUniqueID(aUniqueID)
      , mMsaaID(aMsaaID)
    {}

    void Dispatch(DocAccessibleChild* aParentIPCDoc) override
    {
      auto tabChild = static_cast<dom::TabChild*>(aParentIPCDoc->Manager());
      MOZ_ASSERT(tabChild);
      Unused << tabChild->SendPDocAccessibleConstructor(mIPCDoc, aParentIPCDoc,
                                                        mUniqueID, mMsaaID,
                                                        IAccessibleHolder());
      mIPCDoc->SetConstructedInParentProcess();
    }

    DocAccessibleChild* mIPCDoc;
    uint64_t            mUniqueID;
    uint32_t            mMsaaID;
  };

  friend struct SerializedChildDocConstructor;

  struct SerializedBindChildDoc final : public DeferredEvent
  {
    SerializedBindChildDoc(DocAccessibleChild* aParentDoc,
                           DocAccessibleChild* aChildDoc, uint64_t aNewParentID)
      : DeferredEvent(aParentDoc)
      , mChildDoc(aChildDoc)
      , mNewParentID(aNewParentID)
    {}

    void Dispatch(DocAccessibleChild* aParentIPCDoc) override
    {
      Unused << aParentIPCDoc->SendBindChildDoc(mChildDoc, mNewParentID);
    }

    DocAccessibleChild* mChildDoc;
    uint64_t            mNewParentID;
  };

  struct SerializedShutdown final : public DeferredEvent
  {
    explicit SerializedShutdown(DocAccessibleChild* aTarget)
      : DeferredEvent(aTarget)
    {
    }

    void Dispatch(DocAccessibleChild* aIPCDoc) override
    {
      aIPCDoc->Shutdown();
    }
  };

  bool mIsRemoteConstructed;
  mscom::ProxyUniquePtr<IAccessible> mParentProxy;
  nsTArray<UniquePtr<DeferredEvent>> mDeferredEvents;
};

} // namespace a11y
} // namespace mozilla

#endif // mozilla_a11y_DocAccessibleChild_h