// 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 "ash/wm/shadow_controller.h"

#include <utility>

#include "ash/shell.h"
#include "ash/wm/shadow.h"
#include "ash/wm/shadow_types.h"
#include "ash/wm/window_properties.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "ui/aura/client/activation_client.h"
#include "ui/aura/env.h"
#include "ui/aura/root_window.h"
#include "ui/aura/window.h"
#include "ui/compositor/layer.h"

using std::make_pair;

namespace ash {
namespace internal {

namespace {

ShadowType GetShadowTypeFromWindow(aura::Window* window) {
  switch (window->type()) {
    case aura::client::WINDOW_TYPE_NORMAL:
    case aura::client::WINDOW_TYPE_PANEL:
    case aura::client::WINDOW_TYPE_MENU:
    case aura::client::WINDOW_TYPE_TOOLTIP:
      return SHADOW_TYPE_RECTANGULAR;
    default:
      break;
  }
  return SHADOW_TYPE_NONE;
}

bool ShouldUseSmallShadowForWindow(aura::Window* window) {
  switch (window->type()) {
    case aura::client::WINDOW_TYPE_MENU:
    case aura::client::WINDOW_TYPE_TOOLTIP:
      return true;
    default:
      break;
  }
  return false;
}

// Returns the shadow style to be applied to |losing_active| when it is losing
// active to |gaining_active|. |gaining_active| may be of a type that hides when
// inactive, and as such we do not want to render |losing_active| as inactive.
Shadow::Style GetShadowStyleForWindowLosingActive(
    aura::Window* losing_active,
    aura::Window* gaining_active) {
  if (gaining_active && aura::client::GetHideOnDeactivate(gaining_active)) {
    aura::Window::Windows::const_iterator it =
        std::find(losing_active->transient_children().begin(),
                  losing_active->transient_children().end(),
                  gaining_active);
    if (it != losing_active->transient_children().end())
      return Shadow::STYLE_ACTIVE;
  }
  return Shadow::STYLE_INACTIVE;
}

}  // namespace

ShadowController::ShadowController()
    : ALLOW_THIS_IN_INITIALIZER_LIST(observer_manager_(this)) {
  aura::Env::GetInstance()->AddObserver(this);
  // Watch for window activation changes.
  aura::client::GetActivationClient(Shell::GetPrimaryRootWindow())->
      AddObserver(this);
}

ShadowController::~ShadowController() {
  aura::client::GetActivationClient(Shell::GetPrimaryRootWindow())->
      RemoveObserver(this);
  aura::Env::GetInstance()->RemoveObserver(this);
}

void ShadowController::OnWindowInitialized(aura::Window* window) {
  observer_manager_.Add(window);
  SetShadowType(window, GetShadowTypeFromWindow(window));
  HandlePossibleShadowVisibilityChange(window);
}

void ShadowController::OnWindowPropertyChanged(aura::Window* window,
                                               const void* key,
                                               intptr_t old) {
  if (key == kShadowTypeKey) {
    HandlePossibleShadowVisibilityChange(window);
    return;
  }
}

void ShadowController::OnWindowBoundsChanged(aura::Window* window,
                                             const gfx::Rect& old_bounds,
                                             const gfx::Rect& new_bounds) {
  Shadow* shadow = GetShadowForWindow(window);
  if (shadow)
    shadow->SetContentBounds(gfx::Rect(new_bounds.size()));
}

void ShadowController::OnWindowDestroyed(aura::Window* window) {
  window_shadows_.erase(window);
  observer_manager_.Remove(window);
}

void ShadowController::OnWindowActivated(aura::Window* gaining_active,
                                         aura::Window* losing_active) {
  if (gaining_active) {
    Shadow* shadow = GetShadowForWindow(gaining_active);
    if (shadow && !ShouldUseSmallShadowForWindow(gaining_active))
      shadow->SetStyle(Shadow::STYLE_ACTIVE);
  }
  if (losing_active) {
    Shadow* shadow = GetShadowForWindow(losing_active);
    if (shadow && !ShouldUseSmallShadowForWindow(losing_active)) {
      shadow->SetStyle(GetShadowStyleForWindowLosingActive(losing_active,
                                                           gaining_active));
    }
  }
}

bool ShadowController::ShouldShowShadowForWindow(aura::Window* window) const {
  const ShadowType type = GetShadowType(window);
  switch (type) {
    case SHADOW_TYPE_NONE:
      return false;
    case SHADOW_TYPE_RECTANGULAR:
      return true;
    default:
      NOTREACHED() << "Unknown shadow type " << type;
      return false;
  }
}

Shadow* ShadowController::GetShadowForWindow(aura::Window* window) {
  WindowShadowMap::const_iterator it = window_shadows_.find(window);
  return it != window_shadows_.end() ? it->second.get() : NULL;
}

void ShadowController::HandlePossibleShadowVisibilityChange(
    aura::Window* window) {
  const bool should_show = ShouldShowShadowForWindow(window);
  Shadow* shadow = GetShadowForWindow(window);
  if (shadow)
    shadow->layer()->SetVisible(should_show);
  else if (should_show && !shadow)
    CreateShadowForWindow(window);
}

void ShadowController::CreateShadowForWindow(aura::Window* window) {
  linked_ptr<Shadow> shadow(new Shadow());
  window_shadows_.insert(make_pair(window, shadow));

  shadow->Init(ShouldUseSmallShadowForWindow(window) ?
               Shadow::STYLE_SMALL : Shadow::STYLE_ACTIVE);
  shadow->SetContentBounds(gfx::Rect(window->bounds().size()));
  shadow->layer()->SetVisible(ShouldShowShadowForWindow(window));
  window->layer()->Add(shadow->layer());
}

}  // namespace internal
}  // namespace ash