// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/ui/sad_tab_helper.h"

#include "build/build_config.h"
#include "chrome/browser/lifetime/browser_shutdown.h"
#include "chrome/browser/preloading/prefetch/no_state_prefetch/chrome_no_state_prefetch_contents_delegate.h"
#include "chrome/browser/resource_coordinator/tab_lifecycle_unit_external.h"
#include "chrome/browser/ui/sad_tab.h"
#include "components/performance_manager/public/mojom/lifecycle.mojom.h"
#include "components/tabs/public/tab_interface.h"
#include "content/common/content_navigation_policy.h"
#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/web_contents.h"

namespace {

SadTabKind SadTabKindFromTerminationStatus(base::TerminationStatus status) {
  switch (status) {
#if BUILDFLAG(IS_CHROMEOS)
    case base::TERMINATION_STATUS_PROCESS_WAS_KILLED_BY_OOM:
      return SAD_TAB_KIND_KILLED_BY_OOM;
#endif
    case base::TERMINATION_STATUS_PROCESS_WAS_KILLED:
    case base::TERMINATION_STATUS_LAUNCH_FAILED:
      return SAD_TAB_KIND_KILLED;
    case base::TERMINATION_STATUS_OOM:
    case base::TERMINATION_STATUS_EVICTED_FOR_MEMORY:
      return SAD_TAB_KIND_OOM;
    default:
      return SAD_TAB_KIND_CRASHED;
  }
}

}  // namespace

SadTabHelper::~SadTabHelper() = default;

DEFINE_USER_DATA(SadTabHelper);

SadTabHelper::SadTabHelper(tabs::TabInterface& tab,
                           content::WebContents* web_contents)
    : content::WebContentsObserver(web_contents),
      scoped_unowned_user_data_(tab.GetUnownedUserDataHost(), *this) {}

// static
SadTabHelper* SadTabHelper::From(tabs::TabInterface* tab) {
  return Get(tab->GetUnownedUserDataHost());
}

void SadTabHelper::ReinstallInWebView() {
  if (sad_tab_) {
    sad_tab_->ReinstallInWebView();
  }
}

void SadTabHelper::RenderFrameCreated(
    content::RenderFrameHost* render_frame_host) {
  if (content::ShouldSkipEarlyCommitPendingForCrashedFrame()) {
    sad_tab_.reset();
  }
}

void SadTabHelper::RenderViewReady() {
  if (!content::ShouldSkipEarlyCommitPendingForCrashedFrame()) {
    sad_tab_.reset();
  }
}

void SadTabHelper::DidFinishNavigation(
    content::NavigationHandle* navigation_handle) {
  if (!content::ShouldSkipEarlyCommitPendingForCrashedFrame()) {
    return;
  }
  // If the navigation did not commit and we went back to the crashed frame,
  // reinstall the sad tab, if needed.
  if (!sad_tab_ && !navigation_handle->HasCommitted() &&
      web_contents()->IsCrashed()) {
    InstallSadTab(web_contents()->GetCrashedStatus());
  }
}

void SadTabHelper::PrimaryMainFrameRenderProcessGone(
    base::TerminationStatus status) {
  // Only show the sad tab if we're not in browser shutdown, so that WebContents
  // objects that are not in a browser (e.g., HTML dialogs) and thus are
  // visible do not flash a sad tab page.
  if (browser_shutdown::HasShutdownStarted()) {
    return;
  }

  if (status == base::TERMINATION_STATUS_EVICTED_FOR_MEMORY) {
    // If the renderer was terminated to prevent an browser OOM crash, discard
    // the tab instead of showing a sad tab, unless the tab is visible. The tab
    // will then be reloaded upon reactivation, which is the same user
    // experience as if the tab had been proactively discarded in response to
    // memory pressure. The discard is performed here because the termination
    // point (in PartitionAlloc) cannot allocate memory to perform the discard
    // itself.
    if (web_contents()->GetVisibility() != content::Visibility::VISIBLE) {
      auto* tab_lifecycle_unit_external =
          resource_coordinator::TabLifecycleUnitExternal::FromWebContents(
              web_contents());

      if (!tab_lifecycle_unit_external &&
          prerender::ChromeNoStatePrefetchContentsDelegate::FromWebContents(
              web_contents())) {
        // No-state prefetch can be evicted for memory with prefetched web
        // contents be hidden but not in a TabStripModel.
        return;
      }
      CHECK(tab_lifecycle_unit_external);
      if (tab_lifecycle_unit_external->DiscardTab(
              ::mojom::LifecycleUnitDiscardReason::URGENT)) {
        return;
      }
    }
  }

  if (sad_tab_) {
    return;
  }

  if (SadTab::ShouldShow(status)) {
    InstallSadTab(status);
  }
}

void SadTabHelper::InstallSadTab(base::TerminationStatus status) {
  sad_tab_ =
      SadTab::Create(web_contents(), SadTabKindFromTerminationStatus(status));
}