// Copyright (c) 2006-2008 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 <algorithm>

#include "base/gfx/point.h"
#include "base/logging.h"
#include "chrome/browser/browser.h"
#include "chrome/browser/browser_about_handler.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/profile.h"
#include "chrome/browser/navigation_controller.h"
#include "chrome/browser/navigation_entry.h"
#include "chrome/browser/render_view_host.h"
#include "chrome/browser/tab_contents_factory.h"
#include "chrome/browser/tab_restore_service.h"
#include "chrome/browser/tabs/tab_strip_model.h"
#include "chrome/browser/tabs/tab_strip_model_order_controller.h"
#include "chrome/browser/user_metrics.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/pref_names.h"
#include "chrome/common/pref_service.h"
#include "chrome/common/stl_util-inl.h"

///////////////////////////////////////////////////////////////////////////////
// TabStripModel, public:

TabStripModel::TabStripModel(TabStripModelDelegate* delegate, Profile* profile)
    : delegate_(delegate),
      profile_(profile),
      selected_index_(kNoTab),
      closing_all_(false),
      order_controller_(NULL) {
  NotificationService::current()->AddObserver(this,
      NOTIFY_TAB_CONTENTS_DESTROYED, NotificationService::AllSources());
  SetOrderController(new TabStripModelOrderController(this));
}

TabStripModel::~TabStripModel() {
  STLDeleteContainerPointers(contents_data_.begin(), contents_data_.end());
  delete order_controller_;
  NotificationService::current()->RemoveObserver(this,
      NOTIFY_TAB_CONTENTS_DESTROYED, NotificationService::AllSources());
}

void TabStripModel::AddObserver(TabStripModelObserver* observer) {
  observers_.AddObserver(observer);
}

void TabStripModel::RemoveObserver(TabStripModelObserver* observer) {
  observers_.RemoveObserver(observer);
}

void TabStripModel::SetOrderController(
    TabStripModelOrderController* order_controller) {
  if (order_controller_)
    delete order_controller_;
  order_controller_ = order_controller;
}

bool TabStripModel::ContainsIndex(int index) const {
  return index >= 0 && index < count();
}

void TabStripModel::AppendTabContents(TabContents* contents, bool foreground) {
  // Tabs opened in the foreground using this method inherit the group of the
  // previously selected tab.
  InsertTabContentsAt(count(), contents, foreground, foreground);
}

void TabStripModel::InsertTabContentsAt(int index,
                                        TabContents* contents,
                                        bool foreground,
                                        bool inherit_group) {
  // In tab dragging situations, if the last tab in the window was detached
  // then the user aborted the drag, we will have the |closing_all_| member
  // set (see DetachTabContentsAt) which will mess with our mojo here. We need
  // to clear this bit.
  closing_all_ = false;

  // Have to get the selected contents before we monkey with |contents_|
  // otherwise we run into problems when we try to change the selected contents
  // since the old contents and the new contents will be the same...
  TabContents* selected_contents = GetSelectedTabContents();
  TabContentsData* data = new TabContentsData(contents);
  if (inherit_group && selected_contents) {
    if (foreground) {
      // Forget any existing relationships, we don't want to make things too
      // confusing by having multiple groups active at the same time.
      ForgetAllOpeners();
    }
    // Anything opened by a link we deem to have an opener.
    data->SetGroup(selected_contents->controller());
  }
  contents_data_.insert(contents_data_.begin() + index, data);

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabInsertedAt(contents, index, foreground));

  if (foreground)
    ChangeSelectedContentsFrom(selected_contents, index, false);
}

void TabStripModel::ReplaceNavigationControllerAt(
    int index, NavigationController* controller) {
  // This appears to be OK with no flicker since no redraw event
  // occurs between the call to add an aditional tab and one to close
  // the previous tab.
  InsertTabContentsAt(index + 1, controller->active_contents(), true, true);
  InternalCloseTabContentsAt(index, false);
}

TabContents* TabStripModel::DetachTabContentsAt(int index) {
  if (contents_data_.empty())
    return NULL;

  DCHECK(ContainsIndex(index));
  TabContents* removed_contents = GetContentsAt(index);
  next_selected_index_ = order_controller_->DetermineNewSelectedIndex(index);
  delete contents_data_.at(index);
  contents_data_.erase(contents_data_.begin() + index);
  if (contents_data_.empty())
    closing_all_ = true;
  TabStripModelObservers::Iterator iter(observers_);
  while (TabStripModelObserver* obs = iter.GetNext()) {
    obs->TabDetachedAt(removed_contents, index);
    if (empty())
      obs->TabStripEmpty();
  }
  if (!contents_data_.empty()) {
    if (index == selected_index_) {
      ChangeSelectedContentsFrom(removed_contents, next_selected_index_,
                                 false);
    } else if (index < selected_index_) {
      // If the removed tab was before the selected index, we need to account
      // for this in the selected index...
      SelectTabContentsAt(selected_index_ - 1, false);
    }
  }
  next_selected_index_ = selected_index_;
  return removed_contents;
}

void TabStripModel::SelectTabContentsAt(int index, bool user_gesture) {
  DCHECK(ContainsIndex(index));
  ChangeSelectedContentsFrom(GetSelectedTabContents(), index, user_gesture);
}

void TabStripModel::ReplaceTabContentsAt(int index,
                                         TabContents* replacement_contents) {
  DCHECK(ContainsIndex(index));
  TabContents* old_contents = GetContentsAt(index);
  contents_data_[index]->contents = replacement_contents;

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabChangedAt(replacement_contents, index));

  // Re-use the logic for selecting tabs to ensure the replacement contents is
  // shown and sized appropriately.
  if (index == selected_index_) {
    FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
        TabSelectedAt(old_contents, replacement_contents, index, false));
  }
}

void TabStripModel::MoveTabContentsAt(int index, int to_position) {
  DCHECK(ContainsIndex(index));
  if (index == to_position)
    return;

  TabContentsData* moved_data = contents_data_.at(index);
  contents_data_.erase(contents_data_.begin() + index);
  contents_data_.insert(contents_data_.begin() + to_position, moved_data);

  selected_index_ = to_position;

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabMoved(moved_data->contents, index, to_position));
}

TabContents* TabStripModel::GetSelectedTabContents() const {
  return GetTabContentsAt(selected_index_);
}

TabContents* TabStripModel::GetTabContentsAt(int index) const {
  if (ContainsIndex(index))
    return GetContentsAt(index);
  return NULL;
}

int TabStripModel::GetIndexOfTabContents(const TabContents* contents) const {
  int index = 0;
  TabContentsDataVector::const_iterator iter = contents_data_.begin();
  for (; iter != contents_data_.end(); ++iter, ++index) {
    if ((*iter)->contents == contents)
      return index;
  }
  return kNoTab;
}

int TabStripModel::GetIndexOfController(
    const NavigationController* controller) const {
  int index = 0;
  TabContentsDataVector::const_iterator iter = contents_data_.begin();
  for (; iter != contents_data_.end(); ++iter, ++index) {
    if ((*iter)->contents->controller() == controller)
      return index;
  }
  return kNoTab;
}

void TabStripModel::UpdateTabContentsStateAt(int index) {
  DCHECK(ContainsIndex(index));

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabChangedAt(GetContentsAt(index), index));
}

void TabStripModel::CloseAllTabs() {
  // Set state so that observers can adjust their behavior to suit this
  // specific condition when CloseTabContentsAt causes a flurry of
  // Close/Detach/Select notifications to be sent.
  closing_all_ = true;
  for (int i = count() - 1; i >= 0; --i)
    CloseTabContentsAt(i);
}

bool TabStripModel::TabsAreLoading() const {
  TabContentsDataVector::const_iterator iter = contents_data_.begin();
  for (; iter != contents_data_.end(); ++iter) {
    if ((*iter)->contents->is_loading())
      return true;
  }
  return false;
}

bool TabStripModel::TabHasUnloadListener(int index) {
  // TODO(beng): this should call through to the delegate, so we can mock it
  //             in testing and then provide better test coverage for features
  //             like "close other tabs".
  WebContents* web_contents = GetContentsAt(index)->AsWebContents();
  if (web_contents) {
    // If the WebContents is not connected yet, then there's no unload
    // handler we can fire even if the WebContents has an unload listener.
    // One case where we hit this is in a tab that has an infinite loop 
    // before load.
    return web_contents->notify_disconnection() && 
        !web_contents->showing_interstitial_page() &&
        web_contents->render_view_host()->HasUnloadListener();
  }
  return false;
}

NavigationController* TabStripModel::GetOpenerOfTabContentsAt(int index) {
  DCHECK(ContainsIndex(index));
  return contents_data_.at(index)->opener;
}

int TabStripModel::GetIndexOfNextTabContentsOpenedBy(
    NavigationController* opener, int start_index, bool use_group) {
  DCHECK(opener);
  DCHECK(ContainsIndex(start_index));

  TabContentsData* start_data = contents_data_.at(start_index);
  TabContentsDataVector::const_iterator iter =
      find(contents_data_.begin(), contents_data_.end(), start_data);
  TabContentsDataVector::const_iterator next;
  for (; iter != contents_data_.end(); ++iter) {
    next = iter + 1;
    if (next == contents_data_.end())
      break;
    if (OpenerMatches(*next, opener, use_group))
      return static_cast<int>(next - contents_data_.begin());
  }
  iter = find(contents_data_.begin(), contents_data_.end(), start_data);
  if (iter != contents_data_.begin()) {
    for (--iter; iter > contents_data_.begin(); --iter) {
      if (OpenerMatches(*iter, opener, use_group))
        return static_cast<int>(iter - contents_data_.begin());
    }
  }
  return kNoTab;
}

int TabStripModel::GetIndexOfLastTabContentsOpenedBy(
    NavigationController* opener, int start_index) {
  DCHECK(opener);
  DCHECK(ContainsIndex(start_index));

  TabContentsData* start_data = contents_data_.at(start_index);
  TabContentsDataVector::const_iterator end =
      find(contents_data_.begin(), contents_data_.end(), start_data);
  TabContentsDataVector::const_iterator iter =
      contents_data_.end();
  TabContentsDataVector::const_iterator next;
  for (; iter != end; --iter) {
    next = iter - 1;
    if (next == end)
      break;
    if ((*next)->opener == opener)
      return static_cast<int>(next - contents_data_.begin());
  }
  return kNoTab;
}

void TabStripModel::ForgetAllOpeners() {
  // Forget all opener memories so we don't do anything weird with tab
  // re-selection ordering.
  TabContentsDataVector::const_iterator iter = contents_data_.begin();
  for (; iter != contents_data_.end(); ++iter)
    (*iter)->ForgetOpener();
}

void TabStripModel::ForgetGroup(TabContents* contents) {
  int index = GetIndexOfTabContents(contents);
  DCHECK(ContainsIndex(index));
  contents_data_.at(index)->SetGroup(NULL);
  contents_data_.at(index)->ForgetOpener();
}

bool TabStripModel::ShouldResetGroupOnSelect(TabContents* contents) const {
  int index = GetIndexOfTabContents(contents);
  DCHECK(ContainsIndex(index));
  return contents_data_.at(index)->reset_group_on_select;
}

TabContents* TabStripModel::AddBlankTab(bool foreground) {
  DCHECK(delegate_);
  TabContents* contents = delegate_->CreateTabContentsForURL(
      delegate_->GetBlankTabURL(), GURL(), profile_, PageTransition::TYPED,
      false, NULL);
  AddTabContents(contents, -1, PageTransition::TYPED, foreground);
  return contents;
}

TabContents* TabStripModel::AddBlankTabAt(int index, bool foreground) {
  DCHECK(delegate_);
  TabContents* contents = delegate_->CreateTabContentsForURL(
      delegate_->GetBlankTabURL(), GURL(), profile_, PageTransition::LINK,
      false, NULL);
  AddTabContents(contents, index, PageTransition::LINK, foreground);
  return contents;
}

void TabStripModel::AddTabContents(TabContents* contents,
                                   int index,
                                   PageTransition::Type transition,
                                   bool foreground) {
  if (transition == PageTransition::LINK) {
    // Only try to be clever if we're opening a LINK.
    index = order_controller_->DetermineInsertionIndex(
        contents, transition, foreground);
  } else {
    // For all other types, respect what was passed to us, normalizing -1s.
    if (index < 0)
      index = count();
  }
  TabContents* last_selected_contents = GetSelectedTabContents();
  // Tabs opened from links inherit the "group" attribute of the Tab from which
  // they were opened. This means when they're closed, that Tab will be
  // selected again.
  bool inherit_group = transition == PageTransition::LINK;
  if (!inherit_group) {
    // Also, any tab opened at the end of the TabStrip with a "TYPED"
    // transition inherit group as well. This covers the cases where the user
    // creates a New Tab (e.g. Ctrl+T, or clicks the New Tab button), or types
    // in the address bar and presses Alt+Enter. This allows for opening a new
    // Tab to quickly look up something. When this Tab is closed, the old one
    // is re-selected, not the next-adjacent.
    inherit_group = transition == PageTransition::TYPED && index == count();
  }
  InsertTabContentsAt(index, contents, foreground, inherit_group);
  if (inherit_group && transition == PageTransition::TYPED)
    contents_data_.at(index)->reset_group_on_select = true;
}

void TabStripModel::CloseSelectedTab() {
  CloseTabContentsAt(selected_index_);
}

void TabStripModel::SelectNextTab() {
  // This may happen during automated testing or if a user somehow buffers
  // many key accelerators.
  if (empty())
    return;

  int next_index = (selected_index_ + 1) % count();
  SelectTabContentsAt(next_index, true);
}

void TabStripModel::SelectPreviousTab() {
  int prev_index = selected_index_ - 1;
  if (prev_index < 0)
    prev_index = count() + prev_index;
  SelectTabContentsAt(prev_index, true);
}

void TabStripModel::SelectLastTab() {
  SelectTabContentsAt(count() - 1, true);
}

void TabStripModel::TearOffTabContents(TabContents* detached_contents,
                                       const gfx::Rect& window_bounds,
                                       const DockInfo& dock_info) {
  DCHECK(detached_contents);
  delegate_->CreateNewStripWithContents(detached_contents, window_bounds,
                                        dock_info);
}

// Context menu functions.
bool TabStripModel::IsContextMenuCommandEnabled(
    int context_index, ContextMenuCommand command_id) {
  DCHECK(command_id > CommandFirst && command_id < CommandLast);
  switch (command_id) {
    case CommandNewTab:
    case CommandReload:
    case CommandCloseTab:
      return true;
    case CommandCloseOtherTabs:
      return count() > 1;
    case CommandCloseTabsToRight:
      return context_index < (count() - 1);
    case CommandCloseTabsOpenedBy: {
      NavigationController* opener =
          GetTabContentsAt(context_index)->controller();
      int next_index =
          GetIndexOfNextTabContentsOpenedBy(opener, context_index, true);
      return next_index != kNoTab;
    }
    case CommandDuplicate:
      if (delegate_)
        return delegate_->CanDuplicateContentsAt(context_index);
      else
        return false;
    default:
      NOTREACHED();
  }
  return false;
}

void TabStripModel::ExecuteContextMenuCommand(
    int context_index, ContextMenuCommand command_id) {
  DCHECK(command_id > CommandFirst && command_id < CommandLast);
  switch (command_id) {
    case CommandNewTab:
      UserMetrics::RecordAction(L"TabContextMenu_NewTab", profile_);
      AddBlankTabAt(context_index + 1, true);
      break;
    case CommandReload:
      UserMetrics::RecordAction(L"TabContextMenu_Reload", profile_);
      GetContentsAt(context_index)->controller()->Reload(true);
      break;
    case CommandDuplicate:
      if (delegate_) {
        UserMetrics::RecordAction(L"TabContextMenu_Duplicate", profile_);
        delegate_->DuplicateContentsAt(context_index);
      }
      break;
    case CommandCloseTab:
      UserMetrics::RecordAction(L"TabContextMenu_CloseTab", profile_);
      CloseTabContentsAt(context_index);
      break;
    case CommandCloseOtherTabs: {
      UserMetrics::RecordAction(L"TabContextMenu_CloseOtherTabs", profile_);
      TabContents* contents = GetTabContentsAt(context_index);
      for (int i = count() - 1; i >= 0; --i) {
        if (GetTabContentsAt(i) != contents)
          CloseTabContentsAt(i);
      }
      break;
    }
    case CommandCloseTabsToRight: {
      UserMetrics::RecordAction(L"TabContextMenu_CloseTabsToRight", profile_);
      for (int i = count() - 1; i > context_index; --i)
        CloseTabContentsAt(i);
      break;
    }
    case CommandCloseTabsOpenedBy: {
      UserMetrics::RecordAction(L"TabContextMenu_CloseTabsOpenedBy", profile_);
      NavigationController* opener =
          GetTabContentsAt(context_index)->controller();

      for (int i = count() - 1; i >= 0; --i) {
        if (OpenerMatches(contents_data_.at(i), opener, true))
          CloseTabContentsAt(i);
      }

      break;
    }
    default:
      NOTREACHED();
  }
}

std::vector<int> TabStripModel::GetIndexesOpenedBy(int index) const {
  std::vector<int> indices;
  NavigationController* opener = GetTabContentsAt(index)->controller();
  for (int i = count() - 1; i >= 0; --i) {
    if (OpenerMatches(contents_data_.at(i), opener, true))
      indices.push_back(i);
  }
  return indices;
}

///////////////////////////////////////////////////////////////////////////////
// TabStripModel, NotificationObserver implementation:

void TabStripModel::Observe(NotificationType type,
                            const NotificationSource& source,
                            const NotificationDetails& details) {
  DCHECK(type == NOTIFY_TAB_CONTENTS_DESTROYED);
  // Sometimes, on qemu, it seems like a TabContents object can be destroyed
  // while we still have a reference to it. We need to break this reference
  // here so we don't crash later.
  int index = GetIndexOfTabContents(Source<TabContents>(source).ptr());
  if (index != TabStripModel::kNoTab) {
    // Note that we only detach the contents here, not close it - it's already
    // been closed. We just want to undo our bookkeeping.
    DetachTabContentsAt(index);
  }
}

///////////////////////////////////////////////////////////////////////////////
// TabStripModel, private:

bool TabStripModel::InternalCloseTabContentsAt(int index,
                                               bool create_historical_tab) {
  TabContents* detached_contents = GetContentsAt(index);

  if (TabHasUnloadListener(index)) {
    // If the page has unload listeners, then we tell the renderer to fire
    // them. Once they have fired, we'll get a message back saying whether
    // to proceed closing the page or not, which sends us back to this method
    // with the HasUnloadListener bit cleared.
    WebContents* web_contents = GetContentsAt(index)->AsWebContents();
    // If we hit this code path, the tab had better be a WebContents tab.
    DCHECK(web_contents);
    web_contents->render_view_host()->FirePageBeforeUnload();
    return false;
  }

  // TODO: Now that we know the tab has no unload/beforeunload listeners,
  // we should be able to do a fast shutdown of the RenderViewProcess.
  // Make sure that we actually do.

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabClosingAt(detached_contents, index));

  const bool add_to_restore_service =
      (detached_contents && create_historical_tab &&
       ShouldAddToTabRestoreService(detached_contents));
  if (detached_contents) {
    if (add_to_restore_service) {
      profile()->GetTabRestoreService()->
          CreateHistoricalTab(detached_contents->controller());
    }
    detached_contents->CloseContents();
    // Closing the TabContents will later call back to us via
    // NotificationObserver and detach it.
  }
  return true;
}

TabContents* TabStripModel::GetContentsAt(int index) const {
  CHECK(ContainsIndex(index)) <<
      "Failed to find: " << index << " in: " << count() << " entries.";
  return contents_data_.at(index)->contents;
}

void TabStripModel::ChangeSelectedContentsFrom(
    TabContents* old_contents, int to_index, bool user_gesture) {
  DCHECK(ContainsIndex(to_index));
  TabContents* new_contents = GetContentsAt(to_index);
  if (old_contents == new_contents)
    return;
  TabContents* last_selected_contents = old_contents;
  int from_index = selected_index_;
  selected_index_ = to_index;

  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
      TabSelectedAt(last_selected_contents, new_contents, selected_index_,
                    user_gesture));
}

void TabStripModel::SetOpenerForContents(TabContents* contents,
                                    TabContents* opener) {
  int index = GetIndexOfTabContents(contents);
  contents_data_.at(index)->opener = opener->controller();
}

bool TabStripModel::ShouldAddToTabRestoreService(TabContents* contents) {
  if (!profile() || profile()->IsOffTheRecord() ||
      !profile()->GetTabRestoreService()) {
    return false;
  }

  Browser* browser =
      Browser::GetBrowserForController(contents->controller(), NULL);
  if (!browser)
    return false; // Browser is null during unit tests.
  return browser->type() == Browser::TYPE_NORMAL;
}

// static
bool TabStripModel::OpenerMatches(TabContentsData* data,
                                  NavigationController* opener,
                                  bool use_group) {
  return data->opener == opener || (use_group && data->group == opener);
}