// 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.

#ifndef WEBKIT_APPCACHE_APPCACHE_SERVICE_H_
#define WEBKIT_APPCACHE_APPCACHE_SERVICE_H_

#include <set>
#include <vector>

#include "base/file_path.h"
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "base/time.h"
#include "net/base/completion_callback.h"
#include "net/base/net_errors.h"
#include "testing/gtest/include/gtest/gtest_prod.h"
#include "webkit/appcache/appcache_storage.h"

class URLRequestContext;

namespace base {
class MessageLoopProxy;
}

namespace appcache {

class AppCacheBackendImpl;
class AppCachePolicy;

// Structure that contains basic info about an appcache.
struct AppCacheInfo {
  AppCacheInfo() {}
  AppCacheInfo(const GURL& manifest_url,
               int64 size,
               base::Time creation_time,
               base::Time last_access_time,
               base::Time last_update_time)
      : manifest_url(manifest_url),
        size(size),
        creation_time(creation_time),
        last_access_time(last_access_time),
        last_update_time(last_update_time) {
  }
  GURL manifest_url;
  int64 size;
  base::Time creation_time;
  base::Time last_access_time;
  base::Time last_update_time;
};

typedef std::vector<AppCacheInfo> AppCacheInfoVector;

// Refcounted container to avoid copying the collection in callbacks.
struct AppCacheInfoCollection
    : public base::RefCountedThreadSafe<AppCacheInfoCollection> {
  virtual ~AppCacheInfoCollection() {}
  std::map<GURL, AppCacheInfoVector> infos_by_origin;
};

// Class that manages the application cache service. Sends notifications
// to many frontends.  One instance per user-profile. Each instance has
// exclusive access to it's cache_directory on disk.
class AppCacheService {
 public:
  AppCacheService();
  virtual ~AppCacheService();

  void Initialize(const FilePath& cache_directory,
                  base::MessageLoopProxy* cache_thread);

  // Purges any memory not needed.
  void PurgeMemory() {
    if (storage_.get())
      storage_->PurgeMemory();
  }

  // Populates 'collection' with info about all of the appcaches stored
  // within the service, 'callback' is invoked upon completion. The service
  // acquires a reference to the 'collection' until until completion.
  // This method always completes asynchronously.
  void GetAllAppCacheInfo(AppCacheInfoCollection* collection,
                          net::CompletionCallback* callback);

  // Deletes the group identified by 'manifest_url', 'callback' is
  // invoked upon completion. Upon completion, the cache group and
  // any resources within the group are no longer loadable and all
  // subresource loads for pages associated with a deleted group
  // will fail. This method always completes asynchronously.
  void DeleteAppCacheGroup(const GURL& manifest_url,
                           net::CompletionCallback* callback);

  // Context for use during cache updates, should only be accessed
  // on the IO thread. We do NOT add a reference to the request context,
  // it is the callers responsibility to ensure that the pointer
  // remains valid while set.
  URLRequestContext* request_context() const { return request_context_; }
  void set_request_context(URLRequestContext* context) {
    request_context_ = context;
  }

  // The appcache policy, may be null, in which case access is always allowed.
  // The service does NOT assume ownership of the policy, it is the callers
  // responsibility to ensure that the pointer remains valid while set.
  AppCachePolicy* appcache_policy() const { return appcache_policy_; }
  void set_appcache_policy(AppCachePolicy* policy) {
    appcache_policy_ = policy;
  }

  // Each child process in chrome uses a distinct backend instance.
  // See chrome/browser/AppCacheDispatcherHost.
  void RegisterBackend(AppCacheBackendImpl* backend_impl);
  void UnregisterBackend(AppCacheBackendImpl* backend_impl);
  AppCacheBackendImpl* GetBackend(int id) const {
    BackendMap::const_iterator it = backends_.find(id);
    return (it != backends_.end()) ? it->second : NULL;
  }

  AppCacheStorage* storage() const { return storage_.get(); }

 protected:
  class AsyncHelper;
  class DeleteHelper;
  class GetInfoHelper;

  typedef std::set<AsyncHelper*> PendingAsyncHelpers;

  AppCachePolicy* appcache_policy_;

  // Deals with persistence.
  scoped_ptr<AppCacheStorage> storage_;

  PendingAsyncHelpers pending_helpers_;

  // Track current processes.  One 'backend' per child process.
  typedef std::map<int, AppCacheBackendImpl*> BackendMap;
  BackendMap backends_;

  // Context for use during cache updates.
  URLRequestContext* request_context_;

  // TODO(jennb): service state: e.g. reached quota?

  DISALLOW_COPY_AND_ASSIGN(AppCacheService);
};

}  // namespace appcache

#endif  // WEBKIT_APPCACHE_APPCACHE_SERVICE_H_