// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// To make sure we can uniquely identify each screenshot tab, add an id as a
// query param to the url that displays the screenshot.
// Note: It's OK that this is a global variable (and not in localStorage),
// because the event page will stay open as long as any screenshot tabs are
// open.
var id = 100;

function takeScreenshot() {
  chrome.tabs.captureVisibleTab(null, function(img) {
    var screenshotUrl = img;
    var viewTabUrl = chrome.extension.getURL('screenshot.html?id=' + id++)

    chrome.tabs.create({url: viewTabUrl}, function(tab) {
      var targetId = tab.id;

      var addSnapshotImageToTab = function(tabId, changedProps) {
        // We are waiting for the tab we opened to finish loading.
        // Check that the the tab's id matches the tab we opened,
        // and that the tab is done loading.
        if (tabId != targetId || changedProps.status != "complete")
          return;

        // Passing the above test means this is the event we were waiting for.
        // There is nothing we need to do for future onUpdated events, so we
        // use removeListner to stop geting called when onUpdated events fire.
        chrome.tabs.onUpdated.removeListener(addSnapshotImageToTab);

        // Look through all views to find the window which will display
        // the screenshot.  The url of the tab which will display the
        // screenshot includes a query parameter with a unique id, which
        // ensures that exactly one view will have the matching URL.
        var views = chrome.extension.getViews();
        for (var i = 0; i < views.length; i++) {
          var view = views[i];
          if (view.location.href == viewTabUrl) {
            view.setScreenshotUrl(screenshotUrl);
            break;
          }
        }
      };
      chrome.tabs.onUpdated.addListener(addSnapshotImageToTab);
    });
  });
}

// Listen for a click on the camera icon.  On that click, take a screenshot.
chrome.browserAction.onClicked.addListener(function(tab) {
  if (tab.url.match("^https?://code.google.com")) {
    takeScreenshot();
  } else {
    alert('This sample can only take screenshots of code.google.com pages');
  }
});