proof-of-concept: display saved duration in extension icon's badge

background.js

@@ -0,0 +1,42 @@
+let savedTimerFormatDuration = function(ms) {
+  let seconds = ms / 1000;
+  let h = Math.floor(seconds/3600);
+  let m = Math.floor((seconds - 3600*h) / 60);
+  let s = Math.floor(seconds - 3600*h - 60*m);
+  console.info(`saved duration: ${h}h:${m}m:${s}s`);
+  if (h === 0 && m === 0) {
+    return `${s}s`;
+  } else {
+    return `${m}m`;
+  }
+}
+
+let savedTimerReset = function() {
+  chrome.storage.sync.remove('saved_durations');
+}
+
+chrome.runtime.onMessage.addListener(
+  function(request, sender, sendResponse) {
+    let vscid = request.vscid;
+
+    chrome.storage.sync.get({saved_durations: {}}, function(store) {
+      if(store.saved_durations[vscid] == null)
+        store.saved_durations[vscid] = 0;
+
+      if(request.stillPlaying) {
+        store.saved_durations["stillPlaying."+vscid] = request.duration;
+      } else {
+        store.saved_durations[vscid] = store.saved_durations[vscid] + request.duration;
+        delete store.saved_durations["stillPlaying."+vscid];
+      }
+
+      let sum = 0;
+      Object
+        .values(store.saved_durations)
+        .forEach(d => sum += d);
+
+      chrome.storage.sync.set(store);
+      chrome.browserAction.setBadgeText({text: savedTimerFormatDuration(sum)});
+    });
+  },
+);

inject.js

@@ -426,6 +426,7 @@ function setupListener() {
       });
       // show the controller for 1000ms if it's hidden.
       runAction("blink", document, null, null);
+      savedTimerRateChanged(event);
     },
     true
   );
@@ -666,6 +667,13 @@ function initializeNow(document) {
     }
     initializeWhenReady(childDocument);
   });
+
+  forEach.call(mediaTags, function (video) {
+    video.addEventListener('playing', savedTimerBegin.bind(this));
+    video.addEventListener('pause', savedTimerEnd);
+    video.addEventListener('waiting', savedTimerEnd);
+  });
+
   log("End initializeNow", 5);
 }
 
@@ -890,3 +898,56 @@ function showController(controller) {
     log("Hiding controller", 5);
   }, 2000);
 }
+
+let savedTimerSetDuration = function(target) {
+  let from = Number(target.dataset['playFrom']);
+  let to = Number(target.dataset['playTo']);
+  let rate = Number(target.dataset['playRate']);
+  let stillPlaying = target.dataset['playStatus'] === "playing";
+
+  if (stillPlaying) {
+    to = Date.now();
+    rate = target.playbackRate;
+  }
+
+  let t = {
+    spentDuration: (to-from),
+    playedDuration: (to-from)*rate,
+  };
+  let diff = Math.floor(t.playedDuration-t.spentDuration);
+
+  chrome.runtime.sendMessage({
+    vscid: target.dataset["vscid"],
+    duration: diff,
+    stillPlaying: stillPlaying,
+  });
+}
+
+let savedTimerBegin = function(e) {
+  e.target.dataset['playStatus'] = "playing";
+  e.target.dataset['playFrom'] = Date.now();
+  e.target.dataset['playRate'] = e.target.playbackRate;
+  e.target.dataset['interval'] = setInterval(function() {
+    savedTimerSetDuration(e.target);
+  }.bind(this), 1000);
+}
+
+let savedTimerEnd = function(e) {
+  if(e.target.dataset['playStatus'] !== "playing") {
+    return;
+  }
+  clearInterval(e.target.dataset['interval']);
+  delete e.target.dataset['interval'];
+  delete e.target.dataset['playStatus'];
+  e.target.dataset['playTo'] = Date.now();
+
+  savedTimerSetDuration(e.target);
+}
+
+let savedTimerRateChanged = function(e) {
+  if (e.target.dataset['playStatus'] !== "playing") {
+    return;
+  }
+  savedTimerEnd(e);
+  savedTimerBegin.bind(this)(e);
+}.bind(this);

manifest.json

@@ -37,5 +37,8 @@
       "js": ["inject.js"]
     }
   ],
+  "background": {
+    "scripts": ["background.js"]
+  },
   "web_accessible_resources": ["inject.css", "shadow.css"]
 }