// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/ime/input_method_win.h"

#include "base/basictypes.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "ui/base/events/event.h"
#include "ui/base/events/event_constants.h"
#include "ui/base/events/event_utils.h"
#include "ui/base/ime/composition_text.h"
#include "ui/base/ime/input_method.h"
#include "ui/base/ime/text_input_client.h"
#include "ui/base/keycodes/keyboard_codes.h"
#include "ui/base/win/hwnd_util.h"

// Extra number of chars before and after selection (or composition) range which
// is returned to IME for improving conversion accuracy.
static const size_t kExtraNumberOfChars = 20;

namespace views {

InputMethodWin::InputMethodWin(internal::InputMethodDelegate* delegate,
                               HWND hwnd,
                               ui::InputMethod* host)
    : hwnd_(hwnd),
      active_(false),
      is_candidate_popup_open_(false),
      direction_(base::i18n::UNKNOWN_DIRECTION),
      pending_requested_direction_(base::i18n::UNKNOWN_DIRECTION),
      host_(host) {
  SetDelegate(delegate);
}

InputMethodWin::~InputMethodWin() {
  if (widget())
    imm32_manager_.DisableIME(hwnd_);
}

void InputMethodWin::Init(Widget* widget) {
  InputMethodBase::Init(widget);

  // Gets the initial input locale and text direction information.
  OnInputLocaleChanged();
}

void InputMethodWin::OnFocus() {
  UpdateIMEState();
}

void InputMethodWin::OnBlur() {
  ConfirmCompositionText();
}

bool InputMethodWin::OnUntranslatedIMEMessage(const base::NativeEvent& event,
                                              NativeEventResult* result) {
  LRESULT original_result = 0;
  BOOL handled = FALSE;
  switch (event.message) {
    case WM_IME_SETCONTEXT:
      original_result = OnImeSetContext(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_IME_STARTCOMPOSITION:
      original_result = OnImeStartComposition(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_IME_COMPOSITION:
      original_result = OnImeComposition(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_IME_ENDCOMPOSITION:
      original_result = OnImeEndComposition(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_IME_REQUEST:
      original_result = OnImeRequest(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_IME_NOTIFY:
      original_result = OnImeNotify(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_CHAR:
    case WM_SYSCHAR:
      original_result = OnChar(
          event.message, event.wParam, event.lParam, &handled);
      break;
    case WM_DEADCHAR:
    case WM_SYSDEADCHAR:
      original_result = OnDeadChar(
          event.message, event.wParam, event.lParam, &handled);
      break;
    default:
      NOTREACHED() << "Unknown IME message:" << event.message;
      break;
  }
  if (result)
    *result = original_result;
  return !!handled;
}

void InputMethodWin::DispatchKeyEvent(const ui::KeyEvent& key) {
  // Handles ctrl-shift key to change text direction and layout alignment.
  if (ui::IMM32Manager::IsRTLKeyboardLayoutInstalled() &&
      !IsTextInputTypeNone()) {
    ui::KeyboardCode code = key.key_code();
    if (key.type() == ui::ET_KEY_PRESSED) {
      if (code == ui::VKEY_SHIFT) {
        base::i18n::TextDirection dir;
        if (ui::IMM32Manager::IsCtrlShiftPressed(&dir))
          pending_requested_direction_ = dir;
      } else if (code != ui::VKEY_CONTROL) {
        pending_requested_direction_ = base::i18n::UNKNOWN_DIRECTION;
      }
    } else if (key.type() == ui::ET_KEY_RELEASED &&
               (code == ui::VKEY_SHIFT || code == ui::VKEY_CONTROL) &&
               pending_requested_direction_ != base::i18n::UNKNOWN_DIRECTION) {
      GetTextInputClient()->ChangeTextDirectionAndLayoutAlignment(
          pending_requested_direction_);
      pending_requested_direction_ = base::i18n::UNKNOWN_DIRECTION;
    }
  }

  DispatchKeyEventPostIME(key);
}

void InputMethodWin::OnTextInputTypeChanged(View* view) {
  if (IsViewFocused(view)) {
    imm32_manager_.CancelIME(hwnd_);
    UpdateIMEState();
  }
  InputMethodBase::OnTextInputTypeChanged(view);
}

void InputMethodWin::OnCaretBoundsChanged(View* view) {
  gfx::Rect rect;
  if (!IsViewFocused(view) || !GetCaretBoundsInWidget(&rect))
    return;
  imm32_manager_.UpdateCaretRect(hwnd_, rect);
}

void InputMethodWin::CancelComposition(View* view) {
  if (IsViewFocused(view))
    imm32_manager_.CancelIME(hwnd_);
}

void InputMethodWin::OnInputLocaleChanged() {
  active_ = imm32_manager_.SetInputLanguage();
  locale_ = imm32_manager_.GetInputLanguageName();
  direction_ = imm32_manager_.GetTextDirection();
  OnInputMethodChanged();
}

std::string InputMethodWin::GetInputLocale() {
  return locale_;
}

base::i18n::TextDirection InputMethodWin::GetInputTextDirection() {
  return direction_;
}

bool InputMethodWin::IsActive() {
  return active_;
}

ui::TextInputClient* InputMethodWin::GetTextInputClient() const {
  if (InputMethodBase::GetTextInputClient())
    return InputMethodBase::GetTextInputClient();

  return host_ ? host_->GetTextInputClient() : NULL;
}

bool InputMethodWin::IsCandidatePopupOpen() const {
  return is_candidate_popup_open_;
}

void InputMethodWin::OnWillChangeFocus(View* focused_before, View* focused) {
  ConfirmCompositionText();
}

void InputMethodWin::OnDidChangeFocus(View* focused_before, View* focused) {
  UpdateIMEState();
}

LRESULT InputMethodWin::OnImeSetContext(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  active_ = (wparam == TRUE);
  if (active_)
    imm32_manager_.CreateImeWindow(hwnd_);

  OnInputMethodChanged();
  return imm32_manager_.SetImeWindowStyle(hwnd_, message, wparam, lparam,
                                          handled);
}

LRESULT InputMethodWin::OnImeStartComposition(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  // We have to prevent WTL from calling ::DefWindowProc() because the function
  // calls ::ImmSetCompositionWindow() and ::ImmSetCandidateWindow() to
  // over-write the position of IME windows.
  *handled = TRUE;

  if (IsTextInputTypeNone())
    return 0;

  // Reset the composition status and create IME windows.
  imm32_manager_.CreateImeWindow(hwnd_);
  imm32_manager_.ResetComposition(hwnd_);
  return 0;
}

LRESULT InputMethodWin::OnImeComposition(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  // We have to prevent WTL from calling ::DefWindowProc() because we do not
  // want for the IMM (Input Method Manager) to send WM_IME_CHAR messages.
  *handled = TRUE;

  if (IsTextInputTypeNone())
    return 0;

  // At first, update the position of the IME window.
  imm32_manager_.UpdateImeWindow(hwnd_);

  // Retrieve the result string and its attributes of the ongoing composition
  // and send it to a renderer process.
  ui::CompositionText composition;
  if (imm32_manager_.GetResult(hwnd_, lparam, &composition.text)) {
    GetTextInputClient()->InsertText(composition.text);
    imm32_manager_.ResetComposition(hwnd_);
    // Fall though and try reading the composition string.
    // Japanese IMEs send a message containing both GCS_RESULTSTR and
    // GCS_COMPSTR, which means an ongoing composition has been finished
    // by the start of another composition.
  }
  // Retrieve the composition string and its attributes of the ongoing
  // composition and send it to a renderer process.
  if (imm32_manager_.GetComposition(hwnd_, lparam, &composition))
    GetTextInputClient()->SetCompositionText(composition);

  return 0;
}

LRESULT InputMethodWin::OnImeEndComposition(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  // Let WTL call ::DefWindowProc() and release its resources.
  *handled = FALSE;

  if (IsTextInputTypeNone())
    return 0;

  if (GetTextInputClient()->HasCompositionText())
    GetTextInputClient()->ClearCompositionText();

  imm32_manager_.ResetComposition(hwnd_);
  imm32_manager_.DestroyImeWindow(hwnd_);
  return 0;
}

LRESULT InputMethodWin::OnImeRequest(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  *handled = FALSE;

  // Should not receive WM_IME_REQUEST message, if IME is disabled.
  const ui::TextInputType type = GetTextInputType();
  if (type == ui::TEXT_INPUT_TYPE_NONE ||
      type == ui::TEXT_INPUT_TYPE_PASSWORD) {
    return 0;
  }

  switch (wparam) {
    case IMR_RECONVERTSTRING:
      *handled = TRUE;
      return OnReconvertString(reinterpret_cast<RECONVERTSTRING*>(lparam));
    case IMR_DOCUMENTFEED:
      *handled = TRUE;
      return OnDocumentFeed(reinterpret_cast<RECONVERTSTRING*>(lparam));
    case IMR_QUERYCHARPOSITION:
      *handled = TRUE;
      return OnQueryCharPosition(reinterpret_cast<IMECHARPOSITION*>(lparam));
    default:
      return 0;
  }
}

LRESULT InputMethodWin::OnImeNotify(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  *handled = FALSE;

  // Update |is_candidate_popup_open_|, whether a candidate window is open.
  switch (wparam) {
  case IMN_OPENCANDIDATE:
    is_candidate_popup_open_ = true;
    break;
  case IMN_CLOSECANDIDATE:
    is_candidate_popup_open_ = false;
    break;
  }

  return 0;
}

LRESULT InputMethodWin::OnChar(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  *handled = TRUE;

  // We need to send character events to the focused text input client event if
  // its text input type is ui::TEXT_INPUT_TYPE_NONE.
  if (GetTextInputClient()) {
    GetTextInputClient()->InsertChar(static_cast<char16>(wparam),
                                     ui::GetModifiersFromKeyState());
  }

  // Explicitly show the system menu at a good location on [Alt]+[Space].
  // Note: Setting |handled| to FALSE for DefWindowProc triggering of the system
  //       menu causes unsdesirable titlebar artifacts in the classic theme.
  if (message == WM_SYSCHAR && wparam == VK_SPACE)
    ui::ShowSystemMenu(hwnd_);

  return 0;
}

LRESULT InputMethodWin::OnDeadChar(
    UINT message, WPARAM wparam, LPARAM lparam, BOOL* handled) {
  *handled = TRUE;

  if (IsTextInputTypeNone())
    return 0;

  if (!GetTextInputClient())
    return 0;

  // Shows the dead character as a composition text, so that the user can know
  // what dead key was pressed.
  ui::CompositionText composition;
  composition.text.assign(1, static_cast<char16>(wparam));
  composition.selection = ui::Range(0, 1);
  composition.underlines.push_back(
      ui::CompositionUnderline(0, 1, SK_ColorBLACK, false));
  GetTextInputClient()->SetCompositionText(composition);
  return 0;
}

LRESULT InputMethodWin::OnDocumentFeed(RECONVERTSTRING* reconv) {
  ui::TextInputClient* client = GetTextInputClient();
  if (!client)
    return 0;

  ui::Range text_range;
  if (!client->GetTextRange(&text_range) || text_range.is_empty())
    return 0;

  bool result = false;
  ui::Range target_range;
  if (client->HasCompositionText())
    result = client->GetCompositionTextRange(&target_range);

  if (!result || target_range.is_empty()) {
    if (!client->GetSelectionRange(&target_range) ||
        !target_range.IsValid()) {
      return 0;
    }
  }

  if (!text_range.Contains(target_range))
    return 0;

  if (target_range.GetMin() - text_range.start() > kExtraNumberOfChars)
    text_range.set_start(target_range.GetMin() - kExtraNumberOfChars);

  if (text_range.end() - target_range.GetMax() > kExtraNumberOfChars)
    text_range.set_end(target_range.GetMax() + kExtraNumberOfChars);

  size_t len = text_range.length();
  size_t need_size = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);

  if (!reconv)
    return need_size;

  if (reconv->dwSize < need_size)
    return 0;

  string16 text;
  if (!GetTextInputClient()->GetTextFromRange(text_range, &text))
    return 0;
  DCHECK_EQ(text_range.length(), text.length());

  reconv->dwVersion = 0;
  reconv->dwStrLen = len;
  reconv->dwStrOffset = sizeof(RECONVERTSTRING);
  reconv->dwCompStrLen =
      client->HasCompositionText() ? target_range.length() : 0;
  reconv->dwCompStrOffset =
      (target_range.GetMin() - text_range.start()) * sizeof(WCHAR);
  reconv->dwTargetStrLen = target_range.length();
  reconv->dwTargetStrOffset = reconv->dwCompStrOffset;

  memcpy((char*)reconv + sizeof(RECONVERTSTRING),
         text.c_str(), len * sizeof(WCHAR));

  // According to Microsft API document, IMR_RECONVERTSTRING and
  // IMR_DOCUMENTFEED should return reconv, but some applications return
  // need_size.
  return reinterpret_cast<LRESULT>(reconv);
}

LRESULT InputMethodWin::OnReconvertString(RECONVERTSTRING* reconv) {
  ui::TextInputClient* client = GetTextInputClient();
  if (!client)
    return 0;

  // If there is a composition string already, we don't allow reconversion.
  if (client->HasCompositionText())
    return 0;

  ui::Range text_range;
  if (!client->GetTextRange(&text_range) || text_range.is_empty())
    return 0;

  ui::Range selection_range;
  if (!client->GetSelectionRange(&selection_range) ||
      selection_range.is_empty()) {
    return 0;
  }

  DCHECK(text_range.Contains(selection_range));

  size_t len = selection_range.length();
  size_t need_size = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);

  if (!reconv)
    return need_size;

  if (reconv->dwSize < need_size)
    return 0;

  // TODO(penghuang): Return some extra context to help improve IME's
  // reconversion accuracy.
  string16 text;
  if (!GetTextInputClient()->GetTextFromRange(selection_range, &text))
    return 0;
  DCHECK_EQ(selection_range.length(), text.length());

  reconv->dwVersion = 0;
  reconv->dwStrLen = len;
  reconv->dwStrOffset = sizeof(RECONVERTSTRING);
  reconv->dwCompStrLen = len;
  reconv->dwCompStrOffset = 0;
  reconv->dwTargetStrLen = len;
  reconv->dwTargetStrOffset = 0;

  memcpy(reinterpret_cast<char*>(reconv) + sizeof(RECONVERTSTRING),
         text.c_str(), len * sizeof(WCHAR));

  // According to Microsft API document, IMR_RECONVERTSTRING and
  // IMR_DOCUMENTFEED should return reconv, but some applications return
  // need_size.
  return reinterpret_cast<LRESULT>(reconv);
}

LRESULT InputMethodWin::OnQueryCharPosition(IMECHARPOSITION *char_positon) {
  if (!char_positon)
    return 0;

  if (char_positon->dwSize < sizeof(IMECHARPOSITION))
    return 0;

  ui::TextInputClient* client = GetTextInputClient();
  if (!client)
    return 0;

  gfx::Rect rect;
  if (!client->GetCompositionCharacterBounds(char_positon->dwCharPos, &rect))
    return 0;

  char_positon->pt.x = rect.x();
  char_positon->pt.y = rect.y();
  char_positon->cLineHeight = rect.height();
  return 1;  // returns non-zero value when succeeded.
}

void InputMethodWin::ConfirmCompositionText() {
  if (!IsTextInputTypeNone()) {
    imm32_manager_.CleanupComposition(hwnd_);
    // Though above line should confirm the client's composition text by sending
    // a result text to us, in case the input method and the client are in
    // inconsistent states, we check the client's composition state again.
    if (GetTextInputClient()->HasCompositionText())
      GetTextInputClient()->ConfirmCompositionText();
  }
}

void InputMethodWin::UpdateIMEState() {
  // Use switch here in case we are going to add more text input types.
  // We disable input method in password field.
  switch (GetTextInputType()) {
    case ui::TEXT_INPUT_TYPE_NONE:
    case ui::TEXT_INPUT_TYPE_PASSWORD:
      imm32_manager_.DisableIME(hwnd_);
      break;
    default:
      imm32_manager_.EnableIME(hwnd_);
      break;
  }
}

}  // namespace views