// 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 "content/browser/geolocation/geolocation_dispatcher_host.h"

#include <map>
#include <set>
#include <utility>

#include "base/bind.h"
#include "content/browser/geolocation/geolocation_provider.h"
#include "content/browser/renderer_host/render_message_filter.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/browser/renderer_host/render_view_host_impl.h"
#include "content/public/browser/geolocation_permission_context.h"
#include "content/common/geolocation_messages.h"
#include "content/common/geoposition.h"

using content::BrowserThread;
using content::GeolocationPermissionContext;
using content::RenderViewHostImpl;

namespace {

void NotifyArbitratorPermissionGranted(
    const GURL& requesting_frame) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  GeolocationProvider::GetInstance()->OnPermissionGranted(requesting_frame);
}

void SendGeolocationPermissionResponse(
    const GURL& requesting_frame, int render_process_id, int render_view_id,
    int bridge_id, bool allowed) {
  RenderViewHostImpl* r = RenderViewHostImpl::FromID(
      render_process_id, render_view_id);
  if (!r)
    return;
  r->Send(new GeolocationMsg_PermissionSet(render_view_id, bridge_id, allowed));

  if (allowed) {
    BrowserThread::PostTask(
        BrowserThread::IO, FROM_HERE,
        base::Bind(&NotifyArbitratorPermissionGranted, requesting_frame));
  }
}

class GeolocationDispatcherHostImpl : public GeolocationDispatcherHost,
                                      public GeolocationObserver {
 public:
  GeolocationDispatcherHostImpl(
      int render_process_id,
      GeolocationPermissionContext* geolocation_permission_context);

  // GeolocationDispatcherHost
  virtual bool OnMessageReceived(const IPC::Message& msg, bool* msg_was_ok);

  // GeolocationObserver
  virtual void OnLocationUpdate(const Geoposition& position);

 private:
  virtual ~GeolocationDispatcherHostImpl();

  void OnRequestPermission(
      int render_view_id, int bridge_id, const GURL& requesting_frame);
  void OnCancelPermissionRequest(
      int render_view_id, int bridge_id, const GURL& requesting_frame);
  void OnStartUpdating(
      int render_view_id, const GURL& requesting_frame,
      bool enable_high_accuracy);
  void OnStopUpdating(int render_view_id);

  // Updates the |location_arbitrator_| with the currently required update
  // options, based on |renderer_update_options_|.
  void RefreshGeolocationObserverOptions();

  int render_process_id_;
  scoped_refptr<GeolocationPermissionContext> geolocation_permission_context_;

  // Iterated when sending location updates to renderer processes. The fan out
  // to individual bridge IDs happens renderer side, in order to minimize
  // context switches.
  // Only used on the IO thread.
  std::set<int> geolocation_renderer_ids_;
  // Maps renderer_id to the location arbitrator update options that correspond
  // to this particular bridge.
  std::map<int, GeolocationObserverOptions> renderer_update_options_;
  // Only set whilst we are registered with the arbitrator.
  GeolocationProvider* location_provider_;

  DISALLOW_COPY_AND_ASSIGN(GeolocationDispatcherHostImpl);
};

GeolocationDispatcherHostImpl::GeolocationDispatcherHostImpl(
    int render_process_id,
    GeolocationPermissionContext* geolocation_permission_context)
    : render_process_id_(render_process_id),
      geolocation_permission_context_(geolocation_permission_context),
      location_provider_(NULL) {
  // This is initialized by ResourceMessageFilter. Do not add any non-trivial
  // initialization here, defer to OnRegisterBridge which is triggered whenever
  // a javascript geolocation object is actually initialized.
}

GeolocationDispatcherHostImpl::~GeolocationDispatcherHostImpl() {
  if (location_provider_)
    location_provider_->RemoveObserver(this);
}

bool GeolocationDispatcherHostImpl::OnMessageReceived(
    const IPC::Message& msg, bool* msg_was_ok) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  *msg_was_ok = true;
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP_EX(GeolocationDispatcherHostImpl, msg, *msg_was_ok)
    IPC_MESSAGE_HANDLER(GeolocationHostMsg_CancelPermissionRequest,
                        OnCancelPermissionRequest)
    IPC_MESSAGE_HANDLER(GeolocationHostMsg_RequestPermission,
                        OnRequestPermission)
    IPC_MESSAGE_HANDLER(GeolocationHostMsg_StartUpdating, OnStartUpdating)
    IPC_MESSAGE_HANDLER(GeolocationHostMsg_StopUpdating, OnStopUpdating)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()
  return handled;
}

void GeolocationDispatcherHostImpl::OnLocationUpdate(
    const Geoposition& geoposition) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  for (std::set<int>::iterator it = geolocation_renderer_ids_.begin();
       it != geolocation_renderer_ids_.end(); ++it) {
    Send(new GeolocationMsg_PositionUpdated(*it, geoposition));
  }
}

void GeolocationDispatcherHostImpl::OnRequestPermission(
    int render_view_id,
    int bridge_id,
    const GURL& requesting_frame) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
           << render_view_id << ":" << bridge_id;
  geolocation_permission_context_->RequestGeolocationPermission(
      render_process_id_, render_view_id, bridge_id,
      requesting_frame,
      base::Bind(
          &SendGeolocationPermissionResponse, requesting_frame,
          render_process_id_, render_view_id, bridge_id));
}

void GeolocationDispatcherHostImpl::OnCancelPermissionRequest(
    int render_view_id,
    int bridge_id,
    const GURL& requesting_frame) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
           << render_view_id << ":" << bridge_id;
  geolocation_permission_context_->CancelGeolocationPermissionRequest(
      render_process_id_, render_view_id, bridge_id,
      requesting_frame);
}

void GeolocationDispatcherHostImpl::OnStartUpdating(
    int render_view_id,
    const GURL& requesting_frame,
    bool enable_high_accuracy) {
  // StartUpdating() can be invoked as a result of high-accuracy mode
  // being enabled / disabled. No need to record the dispatcher again.
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
           << render_view_id;
  if (!geolocation_renderer_ids_.count(render_view_id))
    geolocation_renderer_ids_.insert(render_view_id);

  renderer_update_options_[render_view_id] =
      GeolocationObserverOptions(enable_high_accuracy);
  RefreshGeolocationObserverOptions();
}

void GeolocationDispatcherHostImpl::OnStopUpdating(int render_view_id) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  DVLOG(1) << __FUNCTION__ << " " << render_process_id_ << ":"
           << render_view_id;
  if (renderer_update_options_.erase(render_view_id))
    RefreshGeolocationObserverOptions();

  DCHECK_EQ(1U, geolocation_renderer_ids_.count(render_view_id));
  geolocation_renderer_ids_.erase(render_view_id);
}

void GeolocationDispatcherHostImpl::RefreshGeolocationObserverOptions() {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  if (renderer_update_options_.empty()) {
    if (location_provider_) {
      location_provider_->RemoveObserver(this);
      location_provider_ = NULL;
    }
  } else {
    if (!location_provider_)
      location_provider_ = GeolocationProvider::GetInstance();
    // Re-add to re-establish our options, in case they changed.
    location_provider_->AddObserver(
        this,
        GeolocationObserverOptions::Collapse(renderer_update_options_));
  }
}
}  // namespace

GeolocationDispatcherHost* GeolocationDispatcherHost::New(
    int render_process_id,
    GeolocationPermissionContext* geolocation_permission_context) {
  return new GeolocationDispatcherHostImpl(
      render_process_id,
      geolocation_permission_context);
}