// 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 "chrome/browser/ui/zoom/zoom_controller.h"

#include "chrome/browser/ui/sad_tab.h"
#include "chrome/browser/ui/zoom/zoom_event_manager.h"
#include "chrome/browser/ui/zoom/zoom_observer.h"
#include "content/public/browser/host_zoom_map.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/page_type.h"
#include "content/public/common/page_zoom.h"
#include "extensions/common/extension.h"
#include "grit/theme_resources.h"
#include "net/base/net_util.h"

DEFINE_WEB_CONTENTS_USER_DATA_KEY(ZoomController);

ZoomController::ZoomController(content::WebContents* web_contents)
    : content::WebContentsObserver(web_contents),
      can_show_bubble_(true),
      zoom_mode_(ZOOM_MODE_DEFAULT),
      zoom_level_(1.0),
      browser_context_(web_contents->GetBrowserContext()) {
  // TODO(wjmaclean) Make calls to HostZoomMap::GetDefaultForBrowserContext()
  // refer to the webcontents-specific HostZoomMap when that becomes available.
  content::HostZoomMap* host_zoom_map =
      content::HostZoomMap::GetDefaultForBrowserContext(browser_context_);
  zoom_level_ = host_zoom_map->GetDefaultZoomLevel();

  zoom_subscription_ = host_zoom_map->AddZoomLevelChangedCallback(
      base::Bind(&ZoomController::OnZoomLevelChanged, base::Unretained(this)));

  UpdateState(std::string());
}

ZoomController::~ZoomController() {}

bool ZoomController::IsAtDefaultZoom() const {
  return content::ZoomValuesEqual(GetZoomLevel(), GetDefaultZoomLevel());
}

int ZoomController::GetResourceForZoomLevel() const {
  if (IsAtDefaultZoom())
    return IDR_ZOOM_NORMAL;
  return GetZoomLevel() > GetDefaultZoomLevel() ? IDR_ZOOM_PLUS
                                                : IDR_ZOOM_MINUS;
}

void ZoomController::AddObserver(ZoomObserver* observer) {
  observers_.AddObserver(observer);
}

void ZoomController::RemoveObserver(ZoomObserver* observer) {
  observers_.RemoveObserver(observer);
}

double ZoomController::GetZoomLevel() const {
  return zoom_mode_ == ZOOM_MODE_MANUAL ?
             zoom_level_:
             content::HostZoomMap::GetZoomLevel(web_contents());
}

int ZoomController::GetZoomPercent() const {
  double zoom_factor = content::ZoomLevelToZoomFactor(GetZoomLevel());
  // Round double for return.
  return static_cast<int>(zoom_factor * 100 + 0.5);
}

bool ZoomController::SetZoomLevel(double zoom_level) {
  // An extension did not initiate this zoom change.
  return SetZoomLevelByExtension(zoom_level, NULL);
}

bool ZoomController::SetZoomLevelByExtension(
    double zoom_level,
    const scoped_refptr<const extensions::Extension>& extension) {
  content::NavigationEntry* entry =
      web_contents()->GetController().GetLastCommittedEntry();
  bool is_normal_page =
      entry && entry->GetPageType() == content::PAGE_TYPE_NORMAL;
  // Cannot zoom in disabled mode. Also, don't allow changing zoom level on
  // a crashed tab, an error page or an interstitial page.
  if (zoom_mode_ == ZOOM_MODE_DISABLED ||
      !web_contents()->GetRenderViewHost()->IsRenderViewLive() ||
      !is_normal_page)
    return false;

  // Store extension data so that |extension| can be attributed when the zoom
  // change completes. We expect that by the time this function returns that
  // any observers that require this information will have requested it.
  last_extension_ = extension;

  // Do not actually rescale the page in manual mode.
  if (zoom_mode_ == ZOOM_MODE_MANUAL) {
    double old_zoom_level = zoom_level_;
    zoom_level_ = zoom_level;

    // TODO(wjmaclean) Do we care about filling in host/scheme here?
    content::HostZoomMap::ZoomLevelChange change;
    change.mode = content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM;
    change.zoom_level = zoom_level;
    ZoomEventManager::GetForBrowserContext(browser_context_)->
        OnZoomLevelChanged(change);

    ZoomChangedEventData zoom_change_data(web_contents(),
                                          old_zoom_level,
                                          zoom_level_,
                                          zoom_mode_,
                                          false /* can_show_bubble */);
    FOR_EACH_OBSERVER(
        ZoomObserver, observers_, OnZoomChanged(zoom_change_data));

    last_extension_ = NULL;
    return true;
  }

  content::HostZoomMap* zoom_map =
      content::HostZoomMap::GetDefaultForBrowserContext(browser_context_);
  DCHECK(zoom_map);
  DCHECK(!event_data_);
  event_data_.reset(new ZoomChangedEventData(web_contents(),
                                             GetZoomLevel(),
                                             zoom_level,
                                             zoom_mode_,
                                             false /* can_show_bubble */));
  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  if (zoom_mode_ == ZOOM_MODE_ISOLATED ||
      zoom_map->UsesTemporaryZoomLevel(render_process_id, render_view_id)) {
    zoom_map->SetTemporaryZoomLevel(
        render_process_id, render_view_id, zoom_level);
  } else {
    if (!entry) {
      last_extension_ = NULL;
      return false;
    }
    std::string host = net::GetHostOrSpecFromURL(entry->GetURL());
    zoom_map->SetZoomLevelForHost(host, zoom_level);
  }

  DCHECK(!event_data_);
  last_extension_ = NULL;
  return true;
}

void ZoomController::SetZoomMode(ZoomMode new_mode) {
  if (new_mode == zoom_mode_)
    return;

  content::HostZoomMap* zoom_map =
      content::HostZoomMap::GetDefaultForBrowserContext(browser_context_);
  DCHECK(zoom_map);
  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  double original_zoom_level = GetZoomLevel();

  DCHECK(!event_data_);
  event_data_.reset(new ZoomChangedEventData(web_contents(),
                                             original_zoom_level,
                                             original_zoom_level,
                                             new_mode,
                                             new_mode != ZOOM_MODE_DEFAULT));

  switch (new_mode) {
    case ZOOM_MODE_DEFAULT: {
      content::NavigationEntry* entry =
          web_contents()->GetController().GetLastCommittedEntry();

      if (entry) {
        GURL url = entry->GetURL();
        std::string host = net::GetHostOrSpecFromURL(url);

        if (zoom_map->HasZoomLevel(url.scheme(), host)) {
          // If there are other tabs with the same origin, then set this tab's
          // zoom level to match theirs. The temporary zoom level will be
          // cleared below, but this call will make sure this tab re-draws at
          // the correct zoom level.
          double origin_zoom_level =
              zoom_map->GetZoomLevelForHostAndScheme(url.scheme(), host);
          event_data_->new_zoom_level = origin_zoom_level;
          zoom_map->SetTemporaryZoomLevel(
              render_process_id, render_view_id, origin_zoom_level);
        } else {
          // The host will need a level prior to removing the temporary level.
          // We don't want the zoom level to change just because we entered
          // default mode.
          zoom_map->SetZoomLevelForHost(host, original_zoom_level);
        }
      }
      // Remove per-tab zoom data for this tab. No event callback expected.
      zoom_map->ClearTemporaryZoomLevel(render_process_id, render_view_id);
      break;
    }
    case ZOOM_MODE_ISOLATED: {
      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
      // page needs an initial isolated zoom back to the same level it was at
      // in the other mode.
      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
        zoom_map->SetTemporaryZoomLevel(
            render_process_id, render_view_id, original_zoom_level);
      } else {
        // When we don't call any HostZoomMap set functions, we send the event
        // manually.
        FOR_EACH_OBSERVER(
            ZoomObserver, observers_, OnZoomChanged(*event_data_));
        event_data_.reset();
      }
      break;
    }
    case ZOOM_MODE_MANUAL: {
      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
      // page needs to be resized to the default zoom. While in manual mode,
      // the zoom level is handled independently.
      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
        zoom_map->SetTemporaryZoomLevel(
            render_process_id, render_view_id, GetDefaultZoomLevel());
        zoom_level_ = original_zoom_level;
      } else {
        // When we don't call any HostZoomMap set functions, we send the event
        // manually.
        FOR_EACH_OBSERVER(
            ZoomObserver, observers_, OnZoomChanged(*event_data_));
        event_data_.reset();
      }
      break;
    }
    case ZOOM_MODE_DISABLED: {
      // The page needs to be zoomed back to default before disabling the zoom
      zoom_map->SetTemporaryZoomLevel(
          render_process_id, render_view_id, GetDefaultZoomLevel());
      break;
    }
  }
  // Any event data we've stored should have been consumed by this point.
  DCHECK(!event_data_);

  zoom_mode_ = new_mode;
}

void ZoomController::DidNavigateMainFrame(
    const content::LoadCommittedDetails& details,
    const content::FrameNavigateParams& params) {
  // If the main frame's content has changed, the new page may have a different
  // zoom level from the old one.
  UpdateState(std::string());
}

void ZoomController::WebContentsDestroyed() {
  // At this point we should no longer be sending any zoom events with this
  // WebContents.
  observers_.Clear();
}

void ZoomController::OnZoomLevelChanged(
    const content::HostZoomMap::ZoomLevelChange& change) {
  UpdateState(change.host);
}

void ZoomController::UpdateState(const std::string& host) {
  // If |host| is empty, all observers should be updated.
  if (!host.empty()) {
    // Use the navigation entry's URL instead of the WebContents' so virtual
    // URLs work (e.g. chrome://settings). http://crbug.com/153950
    content::NavigationEntry* entry =
        web_contents()->GetController().GetLastCommittedEntry();
    if (!entry ||
        host != net::GetHostOrSpecFromURL(entry->GetURL())) {
      return;
    }
  }

  // The zoom bubble should not be shown for zoom changes where the host is
  // empty.
  bool can_show_bubble = can_show_bubble_ && !host.empty();

  if (event_data_) {
    // For state changes initiated within the ZoomController, information about
    // the change should be sent.
    ZoomChangedEventData zoom_change_data = *event_data_;
    event_data_.reset();
    zoom_change_data.can_show_bubble = can_show_bubble;
    FOR_EACH_OBSERVER(
        ZoomObserver, observers_, OnZoomChanged(zoom_change_data));
  } else {
    // TODO(wjmaclean) Should we consider having HostZoomMap send both old and
    // new zoom levels here?
    double zoom_level = GetZoomLevel();
    ZoomChangedEventData zoom_change_data(
        web_contents(), zoom_level, zoom_level, zoom_mode_, can_show_bubble);
    FOR_EACH_OBSERVER(
        ZoomObserver, observers_, OnZoomChanged(zoom_change_data));
  }
}