// Copyright (c) 2011 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 "views/controls/combobox/native_combobox_views.h"

#include <algorithm>

#include "base/command_line.h"
#include "ui/base/keycodes/keyboard_codes.h"
#include "ui/base/models/combobox_model.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/canvas_skia.h"
#include "ui/gfx/font.h"
#include "ui/gfx/path.h"
#include "views/background.h"
#include "views/border.h"
#include "views/controls/combobox/combobox.h"
#include "views/controls/focusable_border.h"
#include "views/controls/menu/submenu_view.h"
#include "views/widget/root_view.h"
#include "views/widget/widget.h"

#if defined(OS_LINUX)
#include "ui/gfx/gtk_util.h"
#endif

namespace {

// A global flag to switch the Combobox wrapper to NativeComboboxViews.
bool combobox_view_enabled = false;

// Define the size of the insets.
const int kTopInsetSize = 4;
const int kLeftInsetSize = 4;
const int kBottomInsetSize = 4;
const int kRightInsetSize = 4;

// Limit how small a combobox can be.
const int kMinComboboxWidth = 148;

// Size of the combobox arrow.
const int kComboboxArrowSize = 9;
const int kComboboxArrowOffset = 7;
const int kComboboxArrowMargin = 12;

// Color settings for text and border.
// These are tentative, and should be derived from theme, system
// settings and current settings.
const SkColor kDefaultBorderColor = SK_ColorGRAY;
const SkColor kTextColor = SK_ColorBLACK;

// Define the id of the first item in the menu (since it needs to be > 0)
const int kFirstMenuItemId = 1000;

}  // namespace

namespace views {

const char NativeComboboxViews::kViewClassName[] =
    "views/NativeComboboxViews";

NativeComboboxViews::NativeComboboxViews(Combobox* parent)
    : combobox_(parent),
      text_border_(new FocusableBorder()),
      dropdown_open_(false),
      selected_item_(-1),
      content_width_(0),
      content_height_(0) {
  set_border(text_border_);
}

NativeComboboxViews::~NativeComboboxViews() {
}

////////////////////////////////////////////////////////////////////////////////
// NativeComboboxViews, View overrides:

bool NativeComboboxViews::OnMousePressed(const views::MouseEvent& mouse_event) {
  combobox_->RequestFocus();
  if (mouse_event.IsLeftMouseButton()) {
    UpdateFromModel();
    ShowDropDownMenu();
  }

  return true;
}

bool NativeComboboxViews::OnMouseDragged(const views::MouseEvent& mouse_event) {
  return true;
}

bool NativeComboboxViews::OnKeyPressed(const views::KeyEvent& key_event) {
  // TODO(oshima): handle IME.
  DCHECK(key_event.type() == ui::ET_KEY_PRESSED);

  // Check if we are in the default state (-1) and set to first item.
  if(selected_item_ == -1)
    selected_item_ = 0;

  int new_item = selected_item_;
  switch(key_event.key_code()){

    // move to the next element if any
    case ui::VKEY_DOWN:
      if (new_item < (combobox_->model()->GetItemCount() - 1))
        new_item++;
      break;

    // move to the end of the list
    case ui::VKEY_END:
    case ui::VKEY_NEXT:
      new_item = combobox_->model()->GetItemCount() - 1;
      break;

    // move to the top of the list
   case ui::VKEY_HOME:
   case ui::VKEY_PRIOR:
      new_item = 0;
      break;

    // move to the previous element if any
    case ui::VKEY_UP:
      if (new_item > 0)
        new_item--;
      break;

    default:
      return false;

  }

  if(new_item != selected_item_) {
    selected_item_ = new_item;
    combobox_->SelectionChanged();
    SchedulePaint();
  }

  return true;
}

bool NativeComboboxViews::OnKeyReleased(const views::KeyEvent& key_event) {
  return true;
}

void NativeComboboxViews::OnPaint(gfx::Canvas* canvas) {
  text_border_->set_has_focus(combobox_->HasFocus());
  OnPaintBackground(canvas);
  PaintText(canvas);
  OnPaintBorder(canvas);
}

void NativeComboboxViews::OnFocus() {
  NOTREACHED();
}

void NativeComboboxViews::OnBlur() {
  NOTREACHED();
}

/////////////////////////////////////////////////////////////////
// NativeComboboxViews, NativeComboboxWrapper overrides:

void NativeComboboxViews::UpdateFromModel() {
  int max_width = 0;
  const gfx::Font &font = GetFont();

  dropdown_list_menu_.reset(new MenuItemView(this));

  int num_items = combobox_->model()->GetItemCount();
  for (int i = 0; i < num_items; ++i) {
    string16 text = combobox_->model()->GetItemAt(i);

    // Inserting the Unicode formatting characters if necessary so that the
    // text is displayed correctly in right-to-left UIs.
    base::i18n::AdjustStringForLocaleDirection(&text);

    dropdown_list_menu_->AppendMenuItem(i + kFirstMenuItemId, UTF16ToWide(text),
         MenuItemView::NORMAL);
     max_width = std::max(max_width, font.GetStringWidth(text));
   }

  content_width_ = max_width;
  content_height_ = font.GetFontSize();
}

void NativeComboboxViews::UpdateSelectedItem() {
  selected_item_ = combobox_->selected_item();
}

void NativeComboboxViews::UpdateEnabled() {
  SetEnabled(combobox_->IsEnabled());
}

int NativeComboboxViews::GetSelectedItem() const {
  return selected_item_;
}

bool NativeComboboxViews::IsDropdownOpen() const {
  return dropdown_open_;
}

gfx::Size NativeComboboxViews::GetPreferredSize() {
  if (content_width_ == 0)
    UpdateFromModel();

  // TODO(saintlou) the preferred size will drive the local bounds
  // which in turn is used to set the minimum width for the dropdown
  gfx::Insets insets = GetInsets();
  return gfx::Size(std::min(kMinComboboxWidth,
                            content_width_ + 2 * (insets.width())),
                   content_height_ + 2 * (insets.height()));
}

View* NativeComboboxViews::GetView() {
  return this;
}

void NativeComboboxViews::SetFocus() {
  text_border_->set_has_focus(true);
}

bool NativeComboboxViews::HandleKeyPressed(const KeyEvent& e) {
  return OnKeyPressed(e);
}

bool NativeComboboxViews::HandleKeyReleased(const KeyEvent& e) {
  return true;
}

void NativeComboboxViews::HandleFocus() {
  SchedulePaint();
}

void NativeComboboxViews::HandleBlur() {
}

gfx::NativeView NativeComboboxViews::GetTestingHandle() const {
  NOTREACHED();
  return NULL;
}

/////////////////////////////////////////////////////////////////
// NativeComboboxViews, views::MenuDelegate overrides:
// (note that the id received is offset by kFirstMenuItemId)

bool NativeComboboxViews::IsItemChecked(int id) const {
  return false;
}

bool NativeComboboxViews::IsCommandEnabled(int id) const {
  return true;
}

void NativeComboboxViews::ExecuteCommand(int id) {
  // revert menu offset to map back to combobox model
  id -= kFirstMenuItemId;
  DCHECK_LT(id, combobox_->model()->GetItemCount());
  selected_item_ = id;
  combobox_->SelectionChanged();
  SchedulePaint();
}

bool NativeComboboxViews::GetAccelerator(int id, views::Accelerator* accel) {
  return false;
}

// static
bool NativeComboboxViews::IsComboboxViewsEnabled() {
#if defined(TOUCH_UI)
  return true;
#else
  return combobox_view_enabled || Widget::IsPureViews();
#endif
}

// static
void NativeComboboxViews::SetEnableComboboxViews(bool enabled) {
  combobox_view_enabled = enabled;
}

/////////////////////////////////////////////////////////////////
// NativeComboboxViews private methods:

const gfx::Font& NativeComboboxViews::GetFont() const {
  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
 #if 0 // For now the width calculation is off so stick with !defined(TOUCH_UI)
  return rb.GetFont(ResourceBundle::LargeFont);
 #else
  return rb.GetFont(ResourceBundle::BaseFont);
 #endif
}

// tip_x and tip_y are the coordinates of the tip of an arrow head which is
// drawn as an isoscele triangle
// shift_x and shift_y are offset from tip_x and tip_y to specify the relative
// positions of the 2 equal angles (ie not the angle at the tip of the arrow)
// Note: the width of the base (the side opposite the tip) is 2 * shift_x
void NativeComboboxViews::DrawArrow(gfx::Canvas* canvas,
                                     int tip_x,
                                     int tip_y,
                                     int shift_x,
                                     int shift_y) const {
  SkPaint paint;
  paint.setStyle(SkPaint::kStrokeAndFill_Style);
  paint.setColor(kTextColor);
  paint.setAntiAlias(true);
  gfx::Path path;
  path.incReserve(4);
  path.moveTo(SkIntToScalar(tip_x), SkIntToScalar(tip_y));
  path.lineTo(SkIntToScalar(tip_x + shift_x), SkIntToScalar(tip_y + shift_y));
  path.lineTo(SkIntToScalar(tip_x - shift_x), SkIntToScalar(tip_y + shift_y));
  path.close();
  canvas->AsCanvasSkia()->drawPath(path, paint);
}


void NativeComboboxViews::PaintText(gfx::Canvas* canvas) {
  gfx::Insets insets = GetInsets();

  canvas->Save();
  canvas->ClipRectInt(insets.left(), insets.top(),
                      width() - insets.width(), height() - insets.height());

  int x = insets.left();
  int y = insets.top();
  int text_height = height() - insets.height();
  SkColor text_color = kTextColor;

  int index = GetSelectedItem();
  if (index < 0 || index > combobox_->model()->GetItemCount())
    index = 0;
  string16 text = combobox_->model()->GetItemAt(index);

  const gfx::Font &font = GetFont();
  int width = font.GetStringWidth(text);

  canvas->DrawStringInt(text, font, text_color, x, y, width, text_height);

  // draw the double arrow
  gfx::Rect lb = GetLocalBounds();
  DrawArrow(canvas,
      lb.width() - (kComboboxArrowSize / 2) - kComboboxArrowOffset,
      lb.height() / 2 - kComboboxArrowSize,
      kComboboxArrowSize / 2,
      kComboboxArrowSize - 2);
  DrawArrow(canvas,
      lb.width() - (kComboboxArrowSize / 2) - kComboboxArrowOffset,
      lb.height() / 2 + kComboboxArrowSize,
      -kComboboxArrowSize / 2,
      -(kComboboxArrowSize - 2));

  // draw the margin
  canvas->DrawLineInt(kDefaultBorderColor,
      lb.width() - kComboboxArrowSize - kComboboxArrowMargin,
      kTopInsetSize,
      lb.width() - kComboboxArrowSize - kComboboxArrowMargin,
      lb.height() - kBottomInsetSize);

  canvas->Restore();
}

void NativeComboboxViews::ShowDropDownMenu() {

  if (!dropdown_list_menu_.get())
    UpdateFromModel();

  // Extend the menu to the width of the combobox.
  SubmenuView* submenu = dropdown_list_menu_->CreateSubmenu();
  submenu->set_minimum_preferred_width(size().width());

  gfx::Rect lb = GetLocalBounds();
  gfx::Point menu_position(lb.origin());
  View::ConvertPointToScreen(this, &menu_position);
  if (menu_position.x() < 0)
      menu_position.set_x(0);

  gfx::Rect bounds(menu_position, lb.size());

  dropdown_open_ = true;
  dropdown_list_menu_->RunMenuAt(NULL, NULL, bounds, MenuItemView::TOPLEFT,
                                 true);
  dropdown_open_ = false;

  // Need to explicitly clear mouse handler so that events get sent
  // properly after the menu finishes running. If we don't do this, then
  // the first click to other parts of the UI is eaten.
  SetMouseHandler(NULL);
}

}  // namespace views