// Copyright (c) 2009 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/dom_ui/dom_ui_thumbnail_source.h"

#include "app/resource_bundle.h"
#include "base/callback.h"
#include "base/command_line.h"
#include "chrome/browser/profile.h"
#include "chrome/browser/thumbnail_store.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/url_constants.h"
#include "gfx/codec/jpeg_codec.h"
#include "googleurl/src/gurl.h"
#include "grit/theme_resources.h"
#include "third_party/skia/include/core/SkBitmap.h"

DOMUIThumbnailSource::DOMUIThumbnailSource(Profile* profile)
    : DataSource(chrome::kChromeUIThumbnailPath, MessageLoop::current()),
      profile_(profile) {
}

void DOMUIThumbnailSource::StartDataRequest(const std::string& path,
                                            bool is_off_the_record,
                                            int request_id) {
  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kThumbnailStore)) {
    scoped_refptr<ThumbnailStore> store_ = profile_->GetThumbnailStore();

    if (!store_->IsReady()) {
      // Register to be notified when the ThumbnailStore is ready.
      if (registrar_.IsEmpty()) {
        registrar_.Add(this, NotificationType::THUMBNAIL_STORE_READY,
            Source<ThumbnailStore>(store_.get()));
      }
      // Insert into pending_requests.
      pending_requests_.push_back(std::make_pair(path, request_id));
    } else {
      DoDataRequest(path, request_id);
    }
    return;
  }  // end --thumbnail-store switch

  HistoryService* hs = profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
  if (hs) {
    HistoryService::Handle handle = hs->GetPageThumbnail(
        GURL(path),
        &cancelable_consumer_,
        NewCallback(this, &DOMUIThumbnailSource::OnThumbnailDataAvailable));
    // Attach the ChromeURLDataManager request ID to the history request.
    cancelable_consumer_.SetClientData(hs, handle, request_id);
  } else {
    // Tell the caller that no thumbnail is available.
    SendResponse(request_id, NULL);
  }
}

void DOMUIThumbnailSource::DoDataRequest(const std::string& path,
                                         int request_id) {
  RefCountedBytes* data = NULL;
  scoped_refptr<ThumbnailStore> store_ = profile_->GetThumbnailStore();
  if (store_->GetPageThumbnail(GURL(path), &data)) {
    // Got the thumbnail.
    SendResponse(request_id, data);
  } else {
    // Don't have the thumbnail so return the default thumbnail.
    if (!default_thumbnail_.get()) {
      default_thumbnail_ =
          ResourceBundle::GetSharedInstance().LoadDataResourceBytes(
              IDR_DEFAULT_THUMBNAIL);
    }
    SendResponse(request_id, default_thumbnail_);
  }
}

void DOMUIThumbnailSource::OnThumbnailDataAvailable(
    HistoryService::Handle request_handle,
    scoped_refptr<RefCountedBytes> data) {
  HistoryService* hs =
      profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
  int request_id = cancelable_consumer_.GetClientData(hs, request_handle);
  // Forward the data along to the networking system.
  if (data.get() && !data->data.empty()) {
    SendResponse(request_id, data);
  } else {
    if (!default_thumbnail_.get()) {
      default_thumbnail_ =
          ResourceBundle::GetSharedInstance().LoadDataResourceBytes(
              IDR_DEFAULT_THUMBNAIL);
    }

    SendResponse(request_id, default_thumbnail_);
  }
}

void DOMUIThumbnailSource::Observe(NotificationType type,
                                   const NotificationSource& source,
                                   const NotificationDetails& details) {
  if (type.value != NotificationType::THUMBNAIL_STORE_READY) {
    NOTREACHED();
    return;
  }

  // This notification is sent only once.
  registrar_.RemoveAll();

  for (size_t i = 0; i < pending_requests_.size(); ++i)
    DoDataRequest(pending_requests_[i].first, pending_requests_[i].second);

  pending_requests_.clear();
}