"use strict";

/**
 * WHOA THERE: We should never be adding new things to EXPECTED_REFLOWS. This
 * is a whitelist that should slowly go away as we improve the performance of
 * the front-end. Instead of adding more reflows to the whitelist, you should
 * be modifying your code to avoid the reflow.
 *
 * See https://developer.mozilla.org/en-US/Firefox/Performance_best_practices_for_Firefox_fe_engineers
 * for tips on how to do that.
 */
const EXPECTED_REFLOWS = [
  /**
   * Nothing here! Please don't add anything new!
   */
];

/*
 * This test ensures that there are no unexpected
 * uninterruptible reflows when closing new tabs.
 */
add_task(async function() {
  await ensureNoPreloadedBrowser();

  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
  await BrowserTestUtils.waitForCondition(() => tab._fullyOpen);

  let tabStripRect = gBrowser.tabContainer.arrowScrollbox.getBoundingClientRect();
  let newTabButtonRect = gBrowser.tabContainer.newTabButton.getBoundingClientRect();
  let inRange = (val, min, max) => min <= val && val <= max;

  // Add a reflow observer and open a new tab.
  await withPerfObserver(
    async function() {
      let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
      gBrowser.removeTab(tab, { animate: true });
      await BrowserTestUtils.waitForEvent(tab, "TabAnimationEnd");
      await switchDone;
    },
    {
      expectedReflows: EXPECTED_REFLOWS,
      frames: {
        filter: rects =>
          rects.filter(
            r =>
              !// We expect all changes to be within the tab strip.
              (
                r.y1 >= tabStripRect.top &&
                r.y2 <= tabStripRect.bottom &&
                r.x1 >= tabStripRect.left &&
                r.x2 <= tabStripRect.right &&
                // The closed tab should disappear at the same time as the previous
                // tab gets selected, causing both tab areas to change color at once:
                // this should be a single rect of the width of 2 tabs, and can
                // include the '+' button if it starts its animation.
                ((r.w > gBrowser.selectedTab.clientWidth &&
                  r.x2 <= newTabButtonRect.right) ||
                  // The '+' icon moves with an animation. At the end of the animation
                  // the former and new positions can touch each other causing the rect
                  // to have twice the icon's width.
                  (r.h == 14 && r.w <= 2 * 14 + kMaxEmptyPixels) ||
                  // We sometimes have a rect for the right most 2px of the '+' button.
                  (r.h == 2 && r.w == 2))
              )
          ),
        exceptions: [
          {
            name:
              "bug 1444886 - the next tab should be selected at the same time" +
              " as the closed one disappears",
            condition: r =>
              // In tab strip
              r.y1 >= tabStripRect.top &&
              r.y2 <= tabStripRect.bottom &&
              r.x1 >= tabStripRect.left &&
              r.x2 <= tabStripRect.right &&
              // Width of one tab plus tab separator(s)
              inRange(gBrowser.selectedTab.clientWidth - r.w, 0, 2),
          },
          {
            name: "bug 1446449 - spurious tab switch spinner",
            condition: r =>
              AppConstants.DEBUG &&
              // In the content area
              r.y1 >=
                document.getElementById("appcontent").getBoundingClientRect()
                  .top,
          },
        ],
      },
    }
  );
  is(EXPECTED_REFLOWS.length, 0, "No reflows are expected when closing a tab");
});