// 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/extensions/api/dial/dial_api.h"

#include <stddef.h>
#include <utility>
#include <vector>

#include "base/bind.h"
#include "base/memory/ptr_util.h"
#include "base/time/time.h"
#include "chrome/browser/extensions/api/dial/device_description_fetcher.h"
#include "chrome/browser/extensions/api/dial/dial_api_factory.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/extensions/api/dial.h"
#include "content/public/browser/browser_thread.h"
#include "extensions/browser/event_router.h"
#include "extensions/browser/extension_system.h"
#include "url/gurl.h"

using base::TimeDelta;
using content::BrowserThread;
using extensions::api::dial::DeviceDescriptionFetcher;
using extensions::api::dial::DialDeviceData;
using extensions::api::dial::DialDeviceDescriptionData;
using extensions::api::dial::DialRegistry;

namespace extensions {

namespace {

// How often to poll for devices.
const int kDialRefreshIntervalSecs = 120;

// We prune a device if it does not respond after this time.
const int kDialExpirationSecs = 240;

// The maximum number of devices retained at once in the registry.
const size_t kDialMaxDevices = 256;

}  // namespace

DialAPI::DialAPI(Profile* profile)
    : RefcountedKeyedService(
          BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)),
      profile_(profile) {
  EventRouter::Get(profile)->RegisterObserver(
      this, api::dial::OnDeviceList::kEventName);
}

DialAPI::~DialAPI() {}

DialRegistry* DialAPI::dial_registry() {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  if (!dial_registry_.get()) {
    dial_registry_.reset(new DialRegistry(
        this, TimeDelta::FromSeconds(kDialRefreshIntervalSecs),
        TimeDelta::FromSeconds(kDialExpirationSecs), kDialMaxDevices));
    if (test_device_data_) {
      dial_registry_->AddDeviceForTest(*test_device_data_);
    }
  }
  return dial_registry_.get();
}

void DialAPI::OnListenerAdded(const EventListenerInfo& details) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  BrowserThread::PostTask(
      BrowserThread::IO, FROM_HERE,
      base::Bind(&DialAPI::NotifyListenerAddedOnIOThread, this));
}

void DialAPI::OnListenerRemoved(const EventListenerInfo& details) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  BrowserThread::PostTask(
      BrowserThread::IO, FROM_HERE,
      base::Bind(&DialAPI::NotifyListenerRemovedOnIOThread, this));
}

void DialAPI::NotifyListenerAddedOnIOThread() {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  VLOG(2) << "DIAL device event listener added.";
  dial_registry()->OnListenerAdded();
}

void DialAPI::NotifyListenerRemovedOnIOThread() {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  VLOG(2) << "DIAL device event listener removed";
  dial_registry()->OnListenerRemoved();
}

void DialAPI::OnDialDeviceEvent(const DialRegistry::DeviceList& devices) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
      base::Bind(&DialAPI::SendEventOnUIThread, this, devices));
}

void DialAPI::OnDialError(const DialRegistry::DialErrorCode code) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
      base::Bind(&DialAPI::SendErrorOnUIThread, this, code));
}

void DialAPI::SendEventOnUIThread(const DialRegistry::DeviceList& devices) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  std::vector<api::dial::DialDevice> args;
  for (const DialDeviceData& device : devices) {
    api::dial::DialDevice api_device;
    device.FillDialDevice(&api_device);
    args.push_back(std::move(api_device));
  }
  std::unique_ptr<base::ListValue> results =
      api::dial::OnDeviceList::Create(args);
  std::unique_ptr<Event> event(new Event(events::DIAL_ON_DEVICE_LIST,
                                         api::dial::OnDeviceList::kEventName,
                                         std::move(results)));
  EventRouter::Get(profile_)->BroadcastEvent(std::move(event));
}

void DialAPI::SendErrorOnUIThread(const DialRegistry::DialErrorCode code) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  api::dial::DialError dial_error;
  switch (code) {
    case DialRegistry::DIAL_NO_LISTENERS:
      dial_error.code = api::dial::DIAL_ERROR_CODE_NO_LISTENERS;
      break;
    case DialRegistry::DIAL_NO_INTERFACES:
      dial_error.code = api::dial::DIAL_ERROR_CODE_NO_VALID_NETWORK_INTERFACES;
      break;
    case DialRegistry::DIAL_CELLULAR_NETWORK:
      dial_error.code = api::dial::DIAL_ERROR_CODE_CELLULAR_NETWORK;
      break;
    case DialRegistry::DIAL_NETWORK_DISCONNECTED:
      dial_error.code = api::dial::DIAL_ERROR_CODE_NETWORK_DISCONNECTED;
      break;
    case DialRegistry::DIAL_SOCKET_ERROR:
      dial_error.code = api::dial::DIAL_ERROR_CODE_SOCKET_ERROR;
      break;
    default:
      dial_error.code = api::dial::DIAL_ERROR_CODE_UNKNOWN;
      break;
  }

  std::unique_ptr<base::ListValue> results =
      api::dial::OnError::Create(dial_error);
  std::unique_ptr<Event> event(new Event(events::DIAL_ON_ERROR,
                                         api::dial::OnError::kEventName,
                                         std::move(results)));
  EventRouter::Get(profile_)->BroadcastEvent(std::move(event));
}

void DialAPI::ShutdownOnUIThread() {}

void DialAPI::SetDeviceForTest(
    const api::dial::DialDeviceData& device_data,
    const api::dial::DialDeviceDescriptionData& device_description) {
  test_device_data_ = base::MakeUnique<DialDeviceData>(device_data);
  test_device_description_ =
      base::MakeUnique<DialDeviceDescriptionData>(device_description);
}

DialDiscoverNowFunction::DialDiscoverNowFunction()
    : dial_(NULL), result_(false) {
}

bool DialDiscoverNowFunction::Prepare() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  DCHECK(browser_context());
  dial_ = DialAPIFactory::GetForBrowserContext(browser_context()).get();
  return true;
}

void DialDiscoverNowFunction::Work() {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  result_ = dial_->dial_registry()->DiscoverNow();
}

bool DialDiscoverNowFunction::Respond() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  SetResult(base::MakeUnique<base::FundamentalValue>(result_));
  return true;
}

DialFetchDeviceDescriptionFunction::DialFetchDeviceDescriptionFunction()
    : dial_(nullptr) {}

DialFetchDeviceDescriptionFunction::~DialFetchDeviceDescriptionFunction() {}

bool DialFetchDeviceDescriptionFunction::RunAsync() {
  dial_ = DialAPIFactory::GetForBrowserContext(browser_context()).get();
  params_ = api::dial::FetchDeviceDescription::Params::Create(*args_);
  EXTENSION_FUNCTION_VALIDATE(params_.get());

  // DialRegistry lives on the IO thread.  Hop on over there to get the URL to
  // fetch.
  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                          base::Bind(&DialFetchDeviceDescriptionFunction::
                                         GetDeviceDescriptionUrlOnIOThread,
                                     this, params_->device_label));
  return true;
}

void DialFetchDeviceDescriptionFunction::GetDeviceDescriptionUrlOnIOThread(
    const std::string& label) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  const GURL& device_description_url =
      dial_->dial_registry()->GetDeviceDescriptionURL(label);
  BrowserThread::PostTask(
      BrowserThread::UI, FROM_HERE,
      base::Bind(&DialFetchDeviceDescriptionFunction::MaybeStartFetch, this,
                 device_description_url));
}

void DialFetchDeviceDescriptionFunction::MaybeStartFetch(const GURL& url) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  if (url.is_empty()) {
    SetError("Device not found");
    SendResponse(false);
    return;
  }

  if (dial_->test_device_data_ && dial_->test_device_description_ &&
      dial_->test_device_data_->device_description_url() == url) {
    OnFetchComplete(*(dial_->test_device_description_));
    return;
  }

  device_description_fetcher_ = base::MakeUnique<DeviceDescriptionFetcher>(
      url, Profile::FromBrowserContext(browser_context()),
      base::BindOnce(&DialFetchDeviceDescriptionFunction::OnFetchComplete,
                     this),
      base::BindOnce(&DialFetchDeviceDescriptionFunction::OnFetchError, this));

  device_description_fetcher_->Start();
}

void DialFetchDeviceDescriptionFunction::OnFetchComplete(
    const api::dial::DialDeviceDescriptionData& result) {
  // Destroy the DeviceDescriptionFetcher since it still contains a reference
  // to |this| in its un-invoked callback.
  device_description_fetcher_.reset();
  api::dial::DialDeviceDescription device_description;
  device_description.device_label = params_->device_label;
  device_description.app_url = result.app_url.spec();
  device_description.device_description = result.device_description;
  SetResult(device_description.ToValue());
  SendResponse(true);
}

void DialFetchDeviceDescriptionFunction::OnFetchError(
    const std::string& message) {
  // Destroy the DeviceDescriptionFetcher since it still contains a reference
  // to |this| in its un-invoked callback.
  device_description_fetcher_.reset();
  SetError(message);
  SendResponse(false);
}

}  // namespace extensions