/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef COBALT_BROWSER_WEB_MODULE_H_
#define COBALT_BROWSER_WEB_MODULE_H_

#include <string>
#include <vector>

#include "base/callback.h"
#include "base/file_path.h"
#include "base/hash_tables.h"
#include "base/message_loop.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/thread.h"
#include "base/threading/thread_checker.h"
#include "cobalt/base/console_commands.h"
#include "cobalt/base/source_location.h"
#include "cobalt/css_parser/parser.h"
#if defined(ENABLE_DEBUG_CONSOLE)
#include "cobalt/debug/debug_server.h"
#include "cobalt/debug/render_overlay.h"
#endif  // ENABLE_DEBUG_CONSOLE
#include "cobalt/dom/csp_delegate.h"
#include "cobalt/dom/dom_settings.h"
#include "cobalt/dom/keyboard_event.h"
#include "cobalt/dom/local_storage_database.h"
#include "cobalt/dom/media_source.h"
#include "cobalt/dom/window.h"
#include "cobalt/dom_parser/parser.h"
#include "cobalt/layout/layout_manager.h"
#include "cobalt/loader/fetcher_factory.h"
#include "cobalt/math/size.h"
#include "cobalt/media/media_module.h"
#include "cobalt/network/network_module.h"
#include "cobalt/render_tree/resource_provider.h"
#include "cobalt/script/global_environment.h"
#include "cobalt/script/javascript_engine.h"
#include "cobalt/script/script_runner.h"
#include "cobalt/webdriver/session_driver.h"
#include "googleurl/src/gurl.h"

namespace cobalt {
namespace browser {

// WebModule hosts all components of Cobalt that deal with or implement the
// WebAPI.  This includes the ability to fetch resources given a URL, parse
// various web formats like HTML and CSS, host a DOM tree, manage a JavaScript
// engine, and lay out a web page.  Ultimately, interaction with WebModule is
// done through calls to InjectEvent() such as when dealing with external input
// (e.g. keyboards and gamepads), and handling render tree output from WebModule
// when it calls the on_render_tree_produced_ callback (provided upon
// construction).
// At creation, the WebModule starts a dedicated thread, on which a private
// implementation object is construted that manages all internal components.
// All methods of the WebModule post tasks to the implementation object on that
// thread, so all internal functions are executed synchronously with respect to
// each other.
// This necessarily implies that details contained within WebModule, such as the
// DOM, are intentionally kept private, since these structures expect to be
// accessed from only one thread.
class WebModule {
 public:
  struct Options {
    typedef base::Callback<scoped_refptr<script::Wrappable>()>
        CreateObjectFunction;
    typedef base::hash_map<std::string, CreateObjectFunction>
        InjectedWindowAttributes;

    // All optional parameters defined in this structure should have their
    // values initialized in the default constructor to useful defaults.
    Options();

    // The name of the WebModule.  This is useful for debugging purposes as in
    // the case where multiple WebModule objects exist, it can be used to
    // differentiate which objects belong to which WebModule.  It is used
    // to name some CVals.
    std::string name;

    // The LayoutTrigger parameter dictates when a layout should be triggered.
    // Tests will often set this up so that layouts are only performed when
    // we specifically request them to be.
    layout::LayoutManager::LayoutTrigger layout_trigger;

    // Optional directory to add to the search path for web files (file://).
    FilePath extra_web_file_dir;

    // The navigation_callback functor will be called when JavaScript internal
    // to the WebModule requests a page navigation, e.g. by modifying
    // 'window.location.href'.
    base::Callback<void(const GURL&)> navigation_callback;

    // A list of callbacks to be called once the web page finishes loading.
    std::vector<base::Closure> loaded_callbacks;

    // injected_window_attributes contains a map of attributes to be injected
    // into the WebModule's window object upon construction.  This provides
    // a mechanism to inject custom APIs into the WebModule object.
    InjectedWindowAttributes injected_window_attributes;

    // Options to customize DOMSettings.
    dom::DOMSettings::Options dom_settings_options;

    // Location policy to enforce, formatted as a Content Security Policy
    // directive, e.g. "h5vcc-location-src 'self'"
    // This is used to implement a navigation jail, so that location
    // can't be changed from the whitelisted origins.
    std::string location_policy;

    // Image cache capaticy in bytes.
    int image_cache_capacity;

    // Typeface cache capacity in bytes.
    int remote_typeface_cache_capacity;

    // Content Security Policy enforcement mode for this web module.
    dom::CspEnforcementType csp_enforcement_mode;

    // Token obtained from CSP to allow creation of insecure delegates.
    int csp_insecure_allowed_token;

    // Whether or not the web module's stat tracker should track event stats.
    bool track_event_stats;

    // If set to something other than 1.0f, when a video starts to play, the
    // image cache will be flushed and temporarily multiplied by this value (
    // must be less than or equal to 1.0f) until the video ends.  This can
    // help for platforms that are low on image memory while playing a video.
    float image_cache_capacity_multiplier_when_playing_video;
  };

  typedef layout::LayoutManager::LayoutResults LayoutResults;
  typedef base::Callback<void(const LayoutResults&)>
      OnRenderTreeProducedCallback;
  typedef base::Callback<void(const GURL&, const std::string&)> OnErrorCallback;

  WebModule(const GURL& initial_url,
            const OnRenderTreeProducedCallback& render_tree_produced_callback,
            const OnErrorCallback& error_callback,
            const base::Closure& window_close_callback,
            media::MediaModule* media_module,
            network::NetworkModule* network_module,
            const math::Size& window_dimensions,
            render_tree::ResourceProvider* resource_provider,
            float layout_refresh_rate, const Options& options = Options());
  ~WebModule();

  // Call this to inject a keyboard event into the web module.
  void InjectKeyboardEvent(const dom::KeyboardEvent::Data& event);

  // Call this to execute Javascript code in this web module.  The calling
  // thread will block until the JavaScript has executed and the output results
  // are available.
  std::string ExecuteJavascript(const std::string& script_utf8,
                                const base::SourceLocation& script_location);

#if defined(ENABLE_WEBDRIVER)
  // Creates a new webdriver::WindowDriver that interacts with the Window that
  // is owned by this WebModule instance.
  scoped_ptr<webdriver::WindowDriver> CreateWindowDriver(
      const webdriver::protocol::WindowId& window_id);
#endif

#if defined(ENABLE_DEBUG_CONSOLE)
  // Gets a reference to the debug server that interacts with this web module.
  // The debug server is part of the debug server module owned by this web
  // module, which is lazily created by this function if necessary.
  debug::DebugServer* GetDebugServer();
#endif  // ENABLE_DEBUG_CONSOLE

  // Suspends the WebModule from creating new render trees, and releases this
  // web module's reference to the resource provider, clearing it out and
  // releasing all references to any resources created from it.
  void Suspend();
  // Resumes the WebModule, possibly with a new resource provider.  This method
  // can only be called if we have previously suspended the WebModule.
  void Resume(render_tree::ResourceProvider* resource_provider);

 private:
  // Data required to construct a WebModule, initialized in the constructor and
  // passed to |Initialize|.
  struct ConstructionData {
    ConstructionData(
        const GURL& initial_url,
        const OnRenderTreeProducedCallback& render_tree_produced_callback,
        const OnErrorCallback& error_callback,
        const base::Closure& window_close_callback,
        media::MediaModule* media_module,
        network::NetworkModule* network_module,
        const math::Size& window_dimensions,
        render_tree::ResourceProvider* resource_provider,
        int dom_max_element_depth, float layout_refresh_rate,
        const Options& options)
        : initial_url(initial_url),
          render_tree_produced_callback(render_tree_produced_callback),
          error_callback(error_callback),
          window_close_callback(window_close_callback),
          media_module(media_module),
          network_module(network_module),
          window_dimensions(window_dimensions),
          resource_provider(resource_provider),
          dom_max_element_depth(dom_max_element_depth),
          layout_refresh_rate(layout_refresh_rate),
          options(options) {}

    GURL initial_url;
    OnRenderTreeProducedCallback render_tree_produced_callback;
    OnErrorCallback error_callback;
    const base::Closure& window_close_callback;
    media::MediaModule* media_module;
    network::NetworkModule* network_module;
    math::Size window_dimensions;
    render_tree::ResourceProvider* resource_provider;
    int dom_max_element_depth;
    float layout_refresh_rate;
    Options options;
  };

  // Forward declaration of the private implementation class.
  class Impl;

  // Destruction observer used to safely tear down this WebModule after the
  // thread has been stopped.
  class DestructionObserver : public MessageLoop::DestructionObserver {
   public:
    explicit DestructionObserver(WebModule* web_module);
    void WillDestroyCurrentMessageLoop() OVERRIDE;

   private:
    WebModule* web_module_;
  };

  // Called by the constructor to create the private implementation object and
  // perform any other initialization required on the dedicated thread.
  void Initialize(const ConstructionData& data);

  void ClearAllIntervalsAndTimeouts();

#if defined(ENABLE_PARTIAL_LAYOUT_CONTROL)
  void OnPartialLayoutConsoleCommandReceived(const std::string& message);
#endif  // defined(ENABLE_PARTIAL_LAYOUT_CONTROL)

  // The message loop this object is running on.
  MessageLoop* message_loop() const { return thread_.message_loop(); }

  // Private implementation object.
  scoped_ptr<Impl> impl_;

  // The thread created and owned by this WebModule.
  // All sub-objects of this object are created on this thread, and all public
  // member functions are re-posted to this thread if necessary.
  base::Thread thread_;

#if defined(ENABLE_PARTIAL_LAYOUT_CONTROL)
  // Handles the 'partial_layout' command.
  scoped_ptr<base::ConsoleCommandManager::CommandHandler>
      partial_layout_command_handler_;
#endif  // defined(ENABLE_PARTIAL_LAYOUT_CONTROL)
};

}  // namespace browser
}  // namespace cobalt

#endif  // COBALT_BROWSER_WEB_MODULE_H_