// Copyright 2020 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/focus_tab_after_navigation_helper.h"

#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/search/search.h"
#include "chrome/browser/ui/browser_window/public/browser_window_interface.h"
#include "chrome/browser/ui/browser_window/public/global_browser_collection.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "chrome/common/webui_url_constants.h"
#include "content/public/browser/browser_url_handler.h"
#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/web_contents.h"
#include "ui/base/base_window.h"

FocusTabAfterNavigationHelper::FocusTabAfterNavigationHelper(
    content::WebContents* contents)
    : content::WebContentsObserver(contents) {}

FocusTabAfterNavigationHelper::~FocusTabAfterNavigationHelper() = default;

void FocusTabAfterNavigationHelper::ReadyToCommitNavigation(
    content::NavigationHandle* navigation) {
  // Focus the tab contents if needed.  This is done at the ReadyToCommit time
  // to:
  // 1) ignore same-document navigations (ReadyToCommitNavigation method is not
  //    invoked for same-document navigations)
  // 2) postpone moving the focus until we are ready to commit the page
  // 3) move the focus before the page starts rendering
  // (only 1 is a hard-requirement;  2 and 3 seem desirable but there are no
  // known scenarios where violating these requirements would lead to bugs).
  if (ShouldFocusTabContents(navigation)) {
    web_contents()->SetInitialFocus();
  }
}

bool FocusTabAfterNavigationHelper::ShouldFocusTabContents(
    content::NavigationHandle* navigation) {
  // Don't focus content in an inactive window or tab.
  BrowserWindowInterface* browser =
      GlobalBrowserCollection::GetInstance()->FindBrowserWithTab(
          web_contents());
  if (!browser) {
    return false;
  }
  if (!browser->GetWindow()->IsActive()) {
    return false;
  }
  if (browser->GetTabStripModel()->GetActiveWebContents() != web_contents()) {
    return false;
  }

  // Don't focus content after subframe navigations.
  if (!navigation->IsInPrimaryMainFrame()) {
    return false;
  }

  // Browser-initiated navigations (e.g. typing in an omnibox) are taken care of
  // in Browser::UpdateUIForNavigationInTab.  See also
  // https://crbug.com/40672083 for possible regression risks related to
  // returning |true| here.
  if (!navigation->IsRendererInitiated()) {
    return false;
  }

  // Renderer-initiated navigations shouldn't focus the tab contents, unless the
  // navigation is leaving the NTP.  See also https://crbug.com/40660393.
  bool started_at_ntp = IsNtpURL(web_contents()->GetLastCommittedURL());
  if (!started_at_ntp) {
    return false;
  }

  // Navigations initiated via chrome.tabs.update and similar APIs should not
  // steal focus from the omnibox.  See also https://crbug.com/40693812.
  if (navigation->GetPageTransition() & ui::PAGE_TRANSITION_FROM_API) {
    return false;
  }

  // Rewrite chrome://newtab to compare with the navigation URL.
  GURL rewritten_ntp_url = web_contents()->GetLastCommittedURL();
  Profile* profile =
      Profile::FromBrowserContext(web_contents()->GetBrowserContext());
  content::BrowserURLHandler::GetInstance()->RewriteURLIfNecessary(
      &rewritten_ntp_url, profile);

  // Focus if the destination is not the NTP.
  return !IsNtpURL(navigation->GetURL()) &&
         (navigation->GetURL() != rewritten_ntp_url);
}

bool FocusTabAfterNavigationHelper::IsNtpURL(const GURL& url) {
  // TODO(lukasza): https://crbug.com/40664076: Try to avoid special-casing
  // kChromeUINewTabURL below and covering it via IsNTPOrRelatedURL instead.
  if (url == chrome::ChromeUINewTabURLAsGURL()) {
    return true;
  }

  Profile* profile =
      Profile::FromBrowserContext(web_contents()->GetBrowserContext());
  return search::IsNTPOrRelatedURL(url, profile);
}