var tabs;

function index(tab) {
  return Array.prototype.indexOf.call(gBrowser.tabs, tab);
}

function indexTest(tab, expectedIndex, msg) {
  var diag = "tab " + tab + " should be at index " + expectedIndex;
  if (msg) {
    msg = msg + " (" + diag + ")";
  } else {
    msg = diag;
  }
  is(index(tabs[tab]), expectedIndex, msg);
}

function PinUnpinHandler(tab, eventName) {
  this.eventCount = 0;
  var self = this;
  tab.addEventListener(
    eventName,
    function () {
      self.eventCount++;
    },
    { capture: true, once: true }
  );
  gBrowser.tabContainer.addEventListener(
    eventName,
    function (e) {
      if (e.originalTarget == tab) {
        self.eventCount++;
      }
    },
    { capture: true, once: true }
  );
}

function test() {
  tabs = [
    gBrowser.selectedTab,
    BrowserTestUtils.addTab(gBrowser),
    BrowserTestUtils.addTab(gBrowser),
    BrowserTestUtils.addTab(gBrowser),
  ];
  indexTest(0, 0);
  indexTest(1, 1);
  indexTest(2, 2);
  indexTest(3, 3);

  // Discard one of the test tabs to verify that pinning/unpinning
  // discarded tabs does not regress (regression test for Bug 1852391).
  gBrowser.discardBrowser(tabs[1], true);

  var eh = new PinUnpinHandler(tabs[3], "TabPinned");
  gBrowser.pinTab(tabs[3]);
  is(eh.eventCount, 2, "TabPinned event should be fired");
  indexTest(0, 1);
  indexTest(1, 2);
  indexTest(2, 3);
  indexTest(3, 0);

  eh = new PinUnpinHandler(tabs[1], "TabPinned");
  gBrowser.pinTab(tabs[1]);
  is(eh.eventCount, 2, "TabPinned event should be fired");
  indexTest(0, 2);
  indexTest(1, 1);
  indexTest(2, 3);
  indexTest(3, 0);

  gBrowser.moveTabTo(tabs[3], 3);
  indexTest(3, 1, "shouldn't be able to mix a pinned tab into normal tabs");

  gBrowser.moveTabTo(tabs[2], 0);
  indexTest(2, 2, "shouldn't be able to mix a normal tab into pinned tabs");

  eh = new PinUnpinHandler(tabs[1], "TabUnpinned");
  gBrowser.unpinTab(tabs[1]);
  is(eh.eventCount, 2, "TabUnpinned event should be fired");
  indexTest(
    1,
    1,
    "unpinning a tab should move a tab to the start of normal tabs"
  );

  eh = new PinUnpinHandler(tabs[3], "TabUnpinned");
  gBrowser.unpinTab(tabs[3]);
  is(eh.eventCount, 2, "TabUnpinned event should be fired");
  indexTest(
    3,
    0,
    "unpinning a tab should move a tab to the start of normal tabs"
  );

  gBrowser.removeTab(tabs[1]);
  gBrowser.removeTab(tabs[2]);
  gBrowser.removeTab(tabs[3]);
}
