<!DOCTYPE HTML>
<html>
<head>
  <title></title>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<script>

SimpleTest.waitForExplicitFinish();

const ACTIONS = [
  "play",
  "pause",
  "seekbackward",
  "seekforward",
  "previoustrack",
  "nexttrack",
  "skipad",
  "seekto",
  "stop",
];

(async function testSetActionHandler() {
  await setupPreference();

  for (const action of ACTIONS) {
    info(`Test setActionHandler for '${action}'`);
    generateAction(action);
    ok(true, "it's ok to do " + action + " without any handler");

    let expectedDetails = generateActionDetails(action);

    let fired = false;
    await setHandlerAndTakeAction(action, details => {
      ok(hasSameValue(details, expectedDetails), "get expected details for " + action);
      fired = !fired;
      clearActionHandler(action);
    });

    generateAction(action);
    ok(fired, "handler of " + action + " is cleared");
  }

  SimpleTest.finish();
})();

function setupPreference() {
  return SpecialPowers.pushPrefEnv({"set": [
    ["dom.media.mediasession.enabled", true],
  ]});
}

function generateAction(action) {
  let details = generateActionDetails(action);
  SpecialPowers.wrap(navigator.mediaSession).notifyHandler(details);
}

function generateActionDetails(action) {
  let details = { action };
  if (action == "seekbackward" || action == "seekforward") {
    details.seekOffset = 3.14159;
  } else if (action == "seekto") {
    details.seekTime = 1.618;
  }
  return details;
}

function setHandlerAndTakeAction(action, handler) {
  let promise = new Promise(resolve => {
    navigator.mediaSession.setActionHandler(action, details => {
      handler(details);
      resolve();
    });
  });
  generateAction(action);
  return promise;
}

function hasSameValue(a, b) {
  // The order of the object matters when stringify the object.
  return JSON.stringify(a) == JSON.stringify(b);
}

function clearActionHandler(action) {
  navigator.mediaSession.setActionHandler(action, null);
}

</script>
</body>
</html>
