// Copyright (c) 2010 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 "chrome/browser/gtk/tabs/dragged_tab_gtk.h"

#include <gdk/gdk.h>

#include <algorithm>

#include "app/x11_util.h"
#include "base/i18n/rtl.h"
#include "chrome/browser/browser_theme_provider.h"
#include "chrome/browser/gtk/gtk_util.h"
#include "chrome/browser/gtk/tabs/tab_renderer_gtk.h"
#include "chrome/browser/profile.h"
#include "chrome/browser/renderer_host/backing_store_x.h"
#include "chrome/browser/renderer_host/render_view_host.h"
#include "chrome/browser/tab_contents/tab_contents.h"
#include "chrome/browser/tabs/tab_strip_model.h"
#include "gfx/canvas_paint.h"
#include "gfx/gtk_util.h"
#include "third_party/skia/include/core/SkShader.h"

namespace {

// The size of the dragged window frame.
const int kDragFrameBorderSize = 1;
const int kTwiceDragFrameBorderSize = 2 * kDragFrameBorderSize;

// Used to scale the dragged window sizes.
const float kScalingFactor = 0.5;

const int kAnimateToBoundsDurationMs = 150;

const gdouble kTransparentAlpha = (200.0f / 255.0f);
const gdouble kOpaqueAlpha = 1.0f;
const double kDraggedTabBorderColor[] = { 103.0 / 0xff,
                                          129.0 / 0xff,
                                          162.0 / 0xff };

}  // namespace

////////////////////////////////////////////////////////////////////////////////
// DraggedTabGtk, public:

DraggedTabGtk::DraggedTabGtk(TabContents* datasource,
                             const gfx::Point& mouse_tab_offset,
                             const gfx::Size& contents_size,
                             bool mini)
    : data_source_(datasource),
      renderer_(new TabRendererGtk(datasource->profile()->GetThemeProvider())),
      attached_(false),
      mouse_tab_offset_(mouse_tab_offset),
      attached_tab_size_(TabRendererGtk::GetMinimumSelectedSize()),
      contents_size_(contents_size),
      close_animation_(this) {
  renderer_->UpdateData(datasource, false, false);
  renderer_->set_mini(mini);

  container_ = gtk_window_new(GTK_WINDOW_POPUP);
  SetContainerColorMap();
  gtk_widget_set_app_paintable(container_, TRUE);
  g_signal_connect(container_, "expose-event",
                   G_CALLBACK(OnExposeEvent), this);
  gtk_widget_add_events(container_, GDK_STRUCTURE_MASK);

  // We contain the tab renderer in a GtkFixed in order to maintain the
  // requested size.  Otherwise, the widget will fill the entire window and
  // cause a crash when rendering because the bounds don't match our images.
  fixed_ = gtk_fixed_new();
  gtk_fixed_put(GTK_FIXED(fixed_), renderer_->widget(), 0, 0);
  gtk_container_add(GTK_CONTAINER(container_), fixed_);
  gtk_widget_show_all(container_);
}

DraggedTabGtk::~DraggedTabGtk() {
  gtk_widget_destroy(container_);
}

void DraggedTabGtk::MoveTo(const gfx::Point& screen_point) {
  int x = screen_point.x() + mouse_tab_offset_.x() -
      ScaleValue(mouse_tab_offset_.x());
  int y = screen_point.y() + mouse_tab_offset_.y() -
      ScaleValue(mouse_tab_offset_.y());

  gtk_window_move(GTK_WINDOW(container_), x, y);
}

void DraggedTabGtk::Attach(int selected_width) {
  attached_ = true;
  Resize(selected_width);

  if (gtk_util::IsScreenComposited())
    gdk_window_set_opacity(container_->window, kOpaqueAlpha);
}

void DraggedTabGtk::Resize(int width) {
  attached_tab_size_.set_width(width);
  ResizeContainer();
}

void DraggedTabGtk::Detach() {
  attached_ = false;
  ResizeContainer();

  if (gtk_util::IsScreenComposited())
    gdk_window_set_opacity(container_->window, kTransparentAlpha);
}

void DraggedTabGtk::Update() {
  gtk_widget_queue_draw(container_);
}

void DraggedTabGtk::AnimateToBounds(const gfx::Rect& bounds,
                                    AnimateToBoundsCallback* callback) {
  animation_callback_.reset(callback);

  gint x, y, width, height;
  gdk_window_get_origin(container_->window, &x, &y);
  gdk_window_get_geometry(container_->window, NULL, NULL,
                          &width, &height, NULL);

  animation_start_bounds_ = gfx::Rect(x, y, width, height);
  animation_end_bounds_ = bounds;

  close_animation_.SetSlideDuration(kAnimateToBoundsDurationMs);
  close_animation_.SetTweenType(SlideAnimation::EASE_OUT);
  if (!close_animation_.IsShowing()) {
    close_animation_.Reset();
    close_animation_.Show();
  }
}

////////////////////////////////////////////////////////////////////////////////
// DraggedTabGtk, AnimationDelegate implementation:

void DraggedTabGtk::AnimationProgressed(const Animation* animation) {
  int delta_x = (animation_end_bounds_.x() - animation_start_bounds_.x());
  int x = animation_start_bounds_.x() +
      static_cast<int>(delta_x * animation->GetCurrentValue());
  int y = animation_end_bounds_.y();
  gdk_window_move(container_->window, x, y);
}

void DraggedTabGtk::AnimationEnded(const Animation* animation) {
  animation_callback_->Run();
}

void DraggedTabGtk::AnimationCanceled(const Animation* animation) {
  AnimationEnded(animation);
}

////////////////////////////////////////////////////////////////////////////////
// DraggedTabGtk, private:

void DraggedTabGtk::Layout() {
  if (attached_) {
    gfx::Size prefsize = GetPreferredSize();
    renderer_->SetBounds(gfx::Rect(0, 0, prefsize.width(), prefsize.height()));
  } else {
    int left = 0;
    if (base::i18n::IsRTL())
      left = GetPreferredSize().width() - attached_tab_size_.width();

    // The renderer_'s width should be attached_tab_size_.width() in both LTR
    // and RTL locales. Wrong width will cause the wrong positioning of the tab
    // view in dragging. Please refer to http://crbug.com/6223 for details.
    renderer_->SetBounds(gfx::Rect(left, 0, attached_tab_size_.width(),
                         attached_tab_size_.height()));
  }
}

gfx::Size DraggedTabGtk::GetPreferredSize() {
  if (attached_)
    return attached_tab_size_;

  int width = std::max(attached_tab_size_.width(), contents_size_.width()) +
      kTwiceDragFrameBorderSize;
  int height = attached_tab_size_.height() + kDragFrameBorderSize +
      contents_size_.height();
  return gfx::Size(width, height);
}

void DraggedTabGtk::ResizeContainer() {
  gfx::Size size = GetPreferredSize();
  gtk_window_resize(GTK_WINDOW(container_),
                    ScaleValue(size.width()), ScaleValue(size.height()));
  Layout();
}

int DraggedTabGtk::ScaleValue(int value) {
  return attached_ ? value : static_cast<int>(value * kScalingFactor);
}

gfx::Rect DraggedTabGtk::bounds() const {
  gint x, y, width, height;
  gtk_window_get_position(GTK_WINDOW(container_), &x, &y);
  gtk_window_get_size(GTK_WINDOW(container_), &width, &height);
  return gfx::Rect(x, y, width, height);
}

void DraggedTabGtk::SetContainerColorMap() {
  GdkScreen* screen = gtk_widget_get_screen(container_);
  GdkColormap* colormap = gdk_screen_get_rgba_colormap(screen);

  // If rgba is not available, use rgb instead.
  if (!colormap)
    colormap = gdk_screen_get_rgb_colormap(screen);

  gtk_widget_set_colormap(container_, colormap);
}

void DraggedTabGtk::SetContainerTransparency() {
  cairo_t* cairo_context = gdk_cairo_create(container_->window);
  if (!cairo_context)
    return;

  // Make the background of the dragged tab window fully transparent.  All of
  // the content of the window (child widgets) will be completely opaque.
  gfx::Size size = bounds().size();
  cairo_scale(cairo_context, static_cast<double>(size.width()),
              static_cast<double>(size.height()));
  cairo_set_source_rgba(cairo_context, 1.0f, 1.0f, 1.0f, 0.0f);
  cairo_set_operator(cairo_context, CAIRO_OPERATOR_SOURCE);
  cairo_paint(cairo_context);
  cairo_destroy(cairo_context);
}

void DraggedTabGtk::SetContainerShapeMask(cairo_surface_t* surface) {
  // Create a 1bpp bitmap the size of |container_|.
  gfx::Size size = bounds().size();
  GdkPixmap* pixmap = gdk_pixmap_new(NULL, size.width(), size.height(), 1);
  cairo_t* cairo_context = gdk_cairo_create(GDK_DRAWABLE(pixmap));

  // Set the transparency.
  cairo_set_source_rgba(cairo_context, 1.0f, 1.0f, 1.0f, 0.0f);

  // Blit the rendered bitmap into a pixmap.  Any pixel set in the pixmap will
  // be opaque in the container window.
  cairo_set_operator(cairo_context, CAIRO_OPERATOR_SOURCE);
  if (!attached_)
    cairo_scale(cairo_context, kScalingFactor, kScalingFactor);
  cairo_set_source_surface(cairo_context, surface, 0, 0);
  cairo_paint(cairo_context);

  if (!attached_) {
    // Make the render area depiction opaque (leaving enough room for the
    // border).
    cairo_identity_matrix(cairo_context);
    cairo_set_source_rgba(cairo_context, 1.0f, 1.0f, 1.0f, 1.0f);
    int tab_height = static_cast<int>(kScalingFactor *
                                      renderer_->height() -
                                      kDragFrameBorderSize);
    cairo_rectangle(cairo_context,
                    0, tab_height,
                    size.width(), size.height() - tab_height);
    cairo_fill(cairo_context);
  }

  cairo_destroy(cairo_context);

  // Set the shape mask.
  gdk_window_shape_combine_mask(container_->window, pixmap, 0, 0);
  g_object_unref(pixmap);
}

// static
gboolean DraggedTabGtk::OnExposeEvent(GtkWidget* widget,
                                      GdkEventExpose* event,
                                      DraggedTabGtk* dragged_tab) {
  cairo_surface_t* surface = dragged_tab->renderer_->PaintToSurface();
  if (gtk_util::IsScreenComposited()) {
    dragged_tab->SetContainerTransparency();
  } else {
    dragged_tab->SetContainerShapeMask(surface);
  }

  // Only used when not attached.
  int tab_width = static_cast<int>(kScalingFactor *
      dragged_tab->renderer_->width());
  int tab_height = static_cast<int>(kScalingFactor *
      dragged_tab->renderer_->height());

  // Draw the render area.
  BackingStore* backing_store =
      dragged_tab->data_source_->render_view_host()->GetBackingStore(false);
  if (backing_store && !dragged_tab->attached_) {
    // This leaves room for the border.
    static_cast<BackingStoreX*>(backing_store)->PaintToRect(
        gfx::Rect(kDragFrameBorderSize, tab_height,
                  widget->allocation.width - kTwiceDragFrameBorderSize,
                  widget->allocation.height - tab_height -
                  kDragFrameBorderSize),
        GDK_DRAWABLE(widget->window));
  }

  cairo_t* cr = gdk_cairo_create(GDK_DRAWABLE(widget->window));
  // Draw the border.
  if (!dragged_tab->attached_) {
    cairo_set_line_width(cr, kDragFrameBorderSize);
    cairo_set_source_rgb(cr, kDraggedTabBorderColor[0],
                             kDraggedTabBorderColor[1],
                             kDraggedTabBorderColor[2]);
    // |offset| is the distance from the edge of the image to the middle of
    // the border line.
    double offset = kDragFrameBorderSize / 2.0 - 0.5;
    double left_x = offset;
    double top_y = tab_height - kDragFrameBorderSize + offset;
    double right_x = widget->allocation.width - offset;
    double bottom_y = widget->allocation.height - offset;
    double middle_x = tab_width + offset;

    // We don't use cairo_rectangle() because we don't want to draw the border
    // under the tab itself.
    cairo_move_to(cr, left_x, top_y);
    cairo_line_to(cr, left_x, bottom_y);
    cairo_line_to(cr, right_x, bottom_y);
    cairo_line_to(cr, right_x, top_y);
    cairo_line_to(cr, middle_x, top_y);
    cairo_stroke(cr);
  }

  // Draw the tab.
  if (!dragged_tab->attached_)
    cairo_scale(cr, kScalingFactor, kScalingFactor);
  cairo_set_source_surface(cr, surface, 0, 0);
  cairo_paint(cr);

  cairo_destroy(cr);

  cairo_surface_destroy(surface);

  // We've already drawn the tab, so don't propagate the expose-event signal.
  return TRUE;
}