/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "PermissionRequestBase.h"

#include "MainThreadUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/Services.h"
#include "nsIDOMWindow.h"
#include "nsIObserverService.h"
#include "nsIPrincipal.h"
#include "nsPIDOMWindow.h"
#include "nsXULAppAPI.h"

namespace mozilla {
namespace dom {
namespace indexedDB {

using namespace mozilla::services;

namespace {

#define IDB_PREFIX "indexedDB"
#define TOPIC_PREFIX IDB_PREFIX "-permissions-"

const char kPermissionString[] = IDB_PREFIX;

const char kPermissionPromptTopic[] = TOPIC_PREFIX "prompt";

#ifdef DEBUG
const char kPermissionResponseTopic[] = TOPIC_PREFIX "response";
#endif

#undef TOPIC_PREFIX
#undef IDB_PREFIX

const uint32_t kPermissionDefault = nsIPermissionManager::UNKNOWN_ACTION;

void
AssertSanity()
{
  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
  MOZ_ASSERT(NS_IsMainThread());
}

} // anonymous namespace

PermissionRequestBase::PermissionRequestBase(nsPIDOMWindow* aWindow,
                                             nsIPrincipal* aPrincipal)
  : mWindow(aWindow)
  , mPrincipal(aPrincipal)
{
  AssertSanity();
  MOZ_ASSERT(aWindow);
  MOZ_ASSERT(aPrincipal);
}

PermissionRequestBase::~PermissionRequestBase()
{
  AssertSanity();
}

// static
nsresult
PermissionRequestBase::GetCurrentPermission(nsIPrincipal* aPrincipal,
                                            PermissionValue* aCurrentValue)
{
  AssertSanity();
  MOZ_ASSERT(aPrincipal);
  MOZ_ASSERT(aCurrentValue);

  nsCOMPtr<nsIPermissionManager> permMan = GetPermissionManager();
  if (NS_WARN_IF(!permMan)) {
    return NS_ERROR_FAILURE;
  }

  uint32_t intPermission;
  nsresult rv = permMan->TestExactPermissionFromPrincipal(
                                                 aPrincipal,
                                                 kPermissionString,
                                                 &intPermission);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  PermissionValue permission =
    PermissionValueForIntPermission(intPermission);

  MOZ_ASSERT(permission == kPermissionAllowed ||
             permission == kPermissionDenied ||
             permission == kPermissionPrompt);

  *aCurrentValue = permission;
  return NS_OK;
}

// static
auto
PermissionRequestBase::PermissionValueForIntPermission(uint32_t aIntPermission)
  -> PermissionValue
{
  AssertSanity();

  // The 'indexedDB' permission is unusual in that the default action is to
  // allow access. Switch that here to make the logic clearer.
  switch (aIntPermission) {
    case kPermissionDefault:
      return kPermissionAllowed;
    case kPermissionAllowed:
      return kPermissionPrompt;
    case kPermissionDenied:
      return kPermissionDenied;
    default:
      MOZ_CRASH("Bad permission!");
  }

  MOZ_CRASH("Should never get here!");
}

nsresult
PermissionRequestBase::PromptIfNeeded(PermissionValue* aCurrentValue)
{
  AssertSanity();
  MOZ_ASSERT(aCurrentValue);
  MOZ_ASSERT(mPrincipal);

  // Tricky, we want to release the window and principal in all cases except
  // when we successfully prompt.
  nsCOMPtr<nsPIDOMWindow> window;
  mWindow.swap(window);

  nsCOMPtr<nsIPrincipal> principal;
  mPrincipal.swap(principal);

  PermissionValue currentValue;
  nsresult rv = GetCurrentPermission(principal, &currentValue);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  MOZ_ASSERT(currentValue != kPermissionDefault);

  if (currentValue == kPermissionPrompt) {
    nsCOMPtr<nsIObserverService> obsSvc = GetObserverService();
    if (NS_WARN_IF(!obsSvc)) {
      return NS_ERROR_FAILURE;
    }

    // We're about to prompt so swap the members back.
    window.swap(mWindow);
    principal.swap(mPrincipal);

    rv = obsSvc->NotifyObservers(static_cast<nsIObserver*>(this),
                                 kPermissionPromptTopic,
                                 nullptr);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      // Finally release if we failed the prompt.
      mWindow = nullptr;
      mPrincipal = nullptr;
      return rv;
    }
  }

  *aCurrentValue = currentValue;
  return NS_OK;
}

void
PermissionRequestBase::SetExplicitPermission(nsIPrincipal* aPrincipal,
                                             uint32_t aIntPermission)
{
  AssertSanity();
  MOZ_ASSERT(aPrincipal);
  MOZ_ASSERT(aIntPermission == kPermissionAllowed ||
             aIntPermission == kPermissionDenied);

  nsCOMPtr<nsIPermissionManager> permMan = GetPermissionManager();
  if (NS_WARN_IF(!permMan)) {
    return;
  }

  nsresult rv = aIntPermission == kPermissionAllowed ?
    permMan->RemoveFromPrincipal(aPrincipal, kPermissionString) :
    permMan->AddFromPrincipal(aPrincipal,
                              kPermissionString,
                              aIntPermission,
                              nsIPermissionManager::EXPIRE_NEVER,
                              /* aExpireTime */ 0);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }
}

NS_IMPL_ISUPPORTS(PermissionRequestBase, nsIObserver, nsIInterfaceRequestor)

NS_IMETHODIMP
PermissionRequestBase::GetInterface(const nsIID& aIID,
                                    void** aResult)
{
  AssertSanity();

  if (aIID.Equals(NS_GET_IID(nsIObserver))) {
    return QueryInterface(aIID, aResult);
  }

  if (aIID.Equals(NS_GET_IID(nsIDOMWindow)) && mWindow) {
    return mWindow->QueryInterface(aIID, aResult);
  }

  *aResult = nullptr;
  return NS_ERROR_NOT_AVAILABLE;
}

NS_IMETHODIMP
PermissionRequestBase::Observe(nsISupports* aSubject,
                               const char* aTopic,
                               const char16_t* aData)
{
  AssertSanity();
  MOZ_ASSERT(!strcmp(aTopic, kPermissionResponseTopic));
  MOZ_ASSERT(mWindow);
  MOZ_ASSERT(mPrincipal);

  nsCOMPtr<nsPIDOMWindow> window;
  mWindow.swap(window);

  nsCOMPtr<nsIPrincipal> principal;
  mPrincipal.swap(principal);

  nsresult rv;
  uint32_t promptResult = nsDependentString(aData).ToInteger(&rv);
  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(rv));

  // The UI prompt code will only return one of these three values. We have to
  // transform it to our values.
  MOZ_ASSERT(promptResult == kPermissionDefault ||
             promptResult == kPermissionAllowed ||
             promptResult == kPermissionDenied);

  if (promptResult != kPermissionDefault) {
    // Save explicitly allowed or denied permissions now.
    SetExplicitPermission(principal, promptResult);
  }

  PermissionValue permission;
  switch (promptResult) {
    case kPermissionDefault:
      permission = kPermissionPrompt;
      break;

    case kPermissionAllowed:
      permission = kPermissionAllowed;
      break;

    case kPermissionDenied:
      permission = kPermissionDenied;
      break;

    default:
      MOZ_CRASH("Bad prompt result!");
  }

  OnPromptComplete(permission);
  return NS_OK;
}

} // namespace indexedDB
} // namespace dom
} // namespace mozilla