// Copyright 2010-2015, Google Inc.
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "win32/tip/tip_ui_handler_immersive.h"

#define _ATL_NO_AUTOMATIC_NAMESPACE
#define _WTL_NO_AUTOMATIC_NAMESPACE
#include <atlbase.h>
#include <atlcom.h>
#include <atlapp.h>
#include <atlmisc.h>
#include <atlwin.h>
#include <msctf.h>

#include <unordered_map>

#include "base/util.h"
#include "session/commands.pb.h"
#include "win32/tip/tip_composition_util.h"
#include "win32/tip/tip_private_context.h"
#include "win32/tip/tip_text_service.h"
#include "win32/tip/tip_ui_element_immersive.h"
#include "win32/tip/tip_ui_element_manager.h"

namespace mozc {
namespace win32 {
namespace tsf {

namespace {

using ATL::CComPtr;
using ATL::CComQIPtr;
using ATL::CWindow;
using WTL::CRect;

using ::mozc::commands::Output;
using ::mozc::commands::Preedit;
typedef ::mozc::commands::Preedit_Segment Segment;
typedef ::mozc::commands::Preedit_Segment::Annotation Annotation;

// Represents the module handle of this module.
volatile HMODULE g_module = nullptr;

// True if the the DLL received DLL_PROCESS_DETACH notification.
volatile bool g_module_unloaded = false;

// Thread Local Storage (TLS) index to specify the current UI thread is
// initialized or not. if ::GetTlsValue(g_tls_index) returns non-zero
// value, the current thread is initialized.
volatile DWORD g_tls_index = TLS_OUT_OF_INDEXES;

using UiElementMap = std::unordered_map<ITfUIElement *, HWND>;

class ThreadLocalInfo {
 public:
  ThreadLocalInfo() {}
  UiElementMap *ui_element_map() {
    return &ui_element_map_;
  }

 private:
  UiElementMap ui_element_map_;

  DISALLOW_COPY_AND_ASSIGN(ThreadLocalInfo);
};

ThreadLocalInfo *GetThreadLocalInfo() {
  if (g_module_unloaded) {
    return nullptr;
  }
  if (g_tls_index == TLS_OUT_OF_INDEXES) {
    return nullptr;
  }
  ThreadLocalInfo *info = static_cast<ThreadLocalInfo *>(
      ::TlsGetValue(g_tls_index));
  if (info != nullptr) {
    // already initialized.
    return info;
  }
  info = new ThreadLocalInfo();
  ::TlsSetValue(g_tls_index, info);
  return info;
}

void EnsureThreadLocalInfoDestroyed() {
  if (g_module_unloaded) {
    return;
  }
  if (g_tls_index == TLS_OUT_OF_INDEXES) {
    return;
  }
  ThreadLocalInfo *info = static_cast<ThreadLocalInfo *>(
      ::TlsGetValue(g_tls_index));
  if (info == nullptr) {
    // already destroyes.
    return;
  }
  delete info;
  ::TlsSetValue(g_tls_index, nullptr);
}

void UpdateUI(TipTextService *text_service, ITfContext *context) {
  if (text_service == nullptr) {
    return;
  }

  ThreadLocalInfo *info = GetThreadLocalInfo();
  if (info == nullptr) {
    return;
  }
  TipPrivateContext *private_context =
      text_service->GetPrivateContext(context);
  if (private_context == nullptr) {
    return;
  }
  private_context->GetUiElementManager()->OnUpdate(text_service, context);
  const UiElementMap &map = *info->ui_element_map();

  const TipUiElementManager::UIElementFlags kUiFlags[] = {
    TipUiElementManager::kSuggestWindow,
    TipUiElementManager::kCandidateWindow,
  };
  for (size_t i = 0; i < arraysize(kUiFlags); ++i) {
    const CComPtr<ITfUIElement> ui_element =
        private_context->GetUiElementManager()->GetElement(kUiFlags[i]);
    if (ui_element) {
      const UiElementMap::const_iterator it = map.find(ui_element);
      if (it == map.end()) {
        continue;
      }
      ::PostMessageW(it->second, WM_MOZC_IMMERSIVE_WINDOW_UPDATE, 0, 0);
    }
  }
}

}  // namespace

ITfUIElement *TipUiHandlerImmersive::CreateUI(TipUiHandler::UiType type,
                                              TipTextService *text_service,
                                              ITfContext *context) {
  switch (type) {
    case TipUiHandler::kSuggestWindow:
    case TipUiHandler::kCandidateWindow: {
      ThreadLocalInfo *info = GetThreadLocalInfo();
      if (info == nullptr) {
        return nullptr;
      }
      HWND window_handle = nullptr;
      CComPtr<ITfUIElement> element(TipUiElementImmersive::New(
          text_service, context, &window_handle));
      if (element == nullptr) {
        return nullptr;
      }
      if (window_handle == nullptr) {
        return nullptr;
      }
      (*info->ui_element_map())[element] = window_handle;
      // pass the ownership to the caller.
      return element.Detach();
    }
    default:
      return nullptr;
  }
}

void TipUiHandlerImmersive::OnDestroyElement(ITfUIElement *element) {
  ThreadLocalInfo *info = GetThreadLocalInfo();
  if (info == nullptr) {
    return;
  }
  UiElementMap::iterator it = info->ui_element_map()->find(element);
  if (it == info->ui_element_map()->end()) {
    return;
  }
  ::DestroyWindow(it->second);
  info->ui_element_map()->erase(it);
}

void TipUiHandlerImmersive::OnActivate() {
  TipUiElementImmersive::OnActivate();
}

void TipUiHandlerImmersive::OnDeactivate() {
  EnsureThreadLocalInfoDestroyed();
  TipUiElementImmersive::OnDeactivate();
}

void TipUiHandlerImmersive::OnFocusChange(
    TipTextService *text_service, ITfDocumentMgr *focused_document_manager) {
  if (!focused_document_manager) {
    // Empty document is not an error.
    return;
  }

  CComPtr<ITfContext> context;
  if (FAILED(focused_document_manager->GetBase(&context))) {
    return;
  }
  if (!context) {
    return;
  }

  UpdateUI(text_service, context);
}

bool TipUiHandlerImmersive::Update(TipTextService *text_service,
                                   ITfContext *context,
                                   TfEditCookie read_cookie) {
  UpdateUI(text_service, context);
  return true;
}

bool TipUiHandlerImmersive::OnDllProcessAttach(HINSTANCE module_handle,
                                               bool static_loading) {
  g_module = module_handle;
  g_tls_index = ::TlsAlloc();
  return TipUiElementImmersive::OnDllProcessAttach(
      module_handle, static_loading);
}

void TipUiHandlerImmersive::OnDllProcessDetach(HINSTANCE module_handle,
                                               bool process_shutdown) {
  if (g_tls_index != TLS_OUT_OF_INDEXES) {
    ::TlsFree(g_tls_index);
    g_tls_index = TLS_OUT_OF_INDEXES;
  }
  g_module_unloaded = true;
  g_module = nullptr;
  TipUiElementImmersive::OnDllProcessDetach(module_handle, process_shutdown);
}

}  // namespace tsf
}  // namespace win32
}  // namespace mozc