{
  'use strict';

  let popupURL = browser.extension.getURL("/ui/popup.html");
  let popupFor = tabId => `${popupURL}#tab${tabId}`;

  let ctxMenuId = "noscript-ctx-menu";

  async function toggleCtxMenuItem(show = ns.local.showCtxMenuItem) {
    if (!"contextMenus" in browser) return;
    let id = ctxMenuId;
    try {
      await browser.contextMenus.remove(id);
    } catch (e) {}

    if (show) {
      browser.contextMenus.create({
        id,
        title: "NoScript",
        contexts: ["all"]
      });
    }
  }

  async function init() {
    await Defaults.init();

    let policyData = (await Storage.get("sync", "policy")).policy;
    if (policyData && policyData.DEFAULT) {
      ns.policy = new Policy(policyData);
    } else {
      await include("/legacy/Legacy.js");
      ns.policy = await Legacy.createOrMigratePolicy();
      await ns.savePolicy();
    }

    await RequestGuard.start();
    await XSS.start(); // we must start it anyway to initialize sub-objects
    if (!ns.sync.xss) {
      XSS.stop();
    }

    Messages.addHandler(messageHandler);

    try {
      await Messages.send("started");
    } catch (e) {
      // no embedder to answer us
    }
    log("STARTED");
    await include("/bg/popupHandler.js");
  };

  let Commands = {
    openPageUI() {
      try {
        browser.browserAction.openPopup();
        return;
      } catch (e) {
        debug(e);
      }
      browser.windows.create({
        url: popupURL,
        width: 800,
        height: 600,
        type: "panel"
      });
    },

    togglePermissions() {},
    install() {
      if ("command" in browser) {
        // keyboard shortcuts
        browser.commands.onCommand.addListener(cmd => {
          if (cmd in Commands) {
            Commands[cmd]();
          }
        });
      }

      if ("contextMenus" in browser) {
        toggleCtxMenuItem();
        browser.contextMenus.onClicked.addListener((info, tab) => {
          if (info.menuItemId == ctxMenuId) {
            this.openPageUI();
          }
        });
      }

      // wiring main UI
      let ba = browser.browserAction;
      if ("setIcon" in ba) {
        //desktop
        ba.setPopup({
          popup: popupURL
        });
      } else {
        // mobile
        ba.onClicked.addListener(async tab => {
          try {
            await browser.tabs.remove(await browser.tabs.query({
              url: popupURL
            }));
          } catch (e) {}
          await browser.tabs.create({
            url: popupFor(tab.id)
          });
        });
      }
    }
  }

  let messageHandler = {
    async updateSettings(settings, sender) {
      await Settings.update(settings);
      toggleCtxMenuItem();
    },

    async broadcastSettings({
      tabId = -1
    }) {
      let policy = ns.policy.dry(true);
      let seen = tabId !== -1 ? await ns.collectSeen(tabId) : null;
      let xssUserChoices = await XSS.getUserChoices();
      await Messages.send("settings", {
        policy,
        seen,
        xssUserChoices,
        local: ns.local,
        sync: ns.sync,
        unrestrictedTab: ns.unrestrictedTabs.has(tabId),
      });
    },

    async exportSettings() {
      return Settings.export();
    },

    async importSettings({data}) {
      return await Settings.import(data);
    },

    fetchChildPolicy({url, contextUrl}, sender) {
      let {tab, frameId} = sender;
      let topUrl = frameId === 0 ? contextUrl : tab && (tab.url || TabCache.get(tab.id));
      let policy = !Sites.isInternal(url) && ns.isEnforced(tab ? tab.id : -1)
        ? ns.policy : null;

      let permissions, unrestricted, cascaded;
      if (policy) {
        let perms = policy.get(url, contextUrl).perms;
        cascaded = topUrl && ns.sync.cascadeRestrictions;
        if (cascaded) {
          perms = policy.cascadeRestrictions(perms, topUrl);
        }
        permissions = perms.dry();
      } else {
        // otherwise either internal URL or unrestricted
        permissions = new Permissions(Permissions.ALL);
        unrestricted = true;
        cascaded = false;
      }
      return {permissions, unrestricted, cascaded};
    },

    async openStandalonePopup() {
      let win = await browser.windows.getLastFocused();
      let [tab] = (await browser.tabs.query({
        lastFocusedWindow: true,
        active: true
      }));

      if (!tab || tab.id === -1) {
        log("No tab found to open the UI for");
        return;
      }
      browser.windows.create({
        url: popupFor(tab.id),
        width: 800,
        height: 600,
        top: win.top + 48,
        left: win.left + 48,
        type: "panel"
      });
    },
  };

  function onSyncMessage(msg, sender) {
    switch(msg.id) {
      case "fetchPolicy":
        return messageHandler.fetchChildPolicy(msg, sender);
      break;
    }
  }

  var ns = {
    running: false,
    policy: null,
    local: null,
    sync: null,
    unrestrictedTabs: new Set(),
    isEnforced(tabId = -1) {
      return this.policy.enforced && (tabId === -1 || !this.unrestrictedTabs.has(tabId));
    },

    requestCan(request, capability) {
      return !this.isEnforced(request.tabId) || this.policy.can(request.url, capability, request.documentURL);
    },

    start() {
      if (this.running) return;
      this.running = true;

      browser.runtime.onSyncMessage.addListener(onSyncMessage);

      deferWebTraffic(init(),
        async () => {
          Commands.install();

          this.devMode = (await browser.management.getSelf()).installType === "development";
          if (this.local.debug) {
            if (this.devMode) {
              include("/test/run.js");
            }
          } else {
            debug = () => {}; // suppress verbosity
          }
        });
    },

    stop() {
      if (!this.running) return;
      this.running = false;
      browser.runtime.onSyncMessage.removeListener(onSyncMessage);
      Messages.removeHandler(messageHandler);
      RequestGuard.stop();
      log("STOPPED");
    },

    async savePolicy() {
      if (this.policy) {
        await Storage.set("sync", {
          policy: this.policy.dry()
        });
        await browser.webRequest.handlerBehaviorChanged()
      }
      return this.policy;
    },



    async save(obj) {
      if (obj && obj.storage) {
        let toBeSaved = {
          [obj.storage]: obj
        };
        await Storage.set(obj.storage, toBeSaved);
      }
      return obj;
    },

    async collectSeen(tabId) {
      try {
        let seen = Array.from(await Messages.send("collect", {}, {tabId, frameId: 0}));
        debug("Collected seen", seen);
        return seen;
      } catch (e) {
        await include("/lib/restricted.js");
        if (!isRestrictedURL((await browser.tabs.get(tabId)).url)) {
          // probably a page where content scripts cannot run, let's open the options instead
          error(e, "Cannot collect noscript activity data");
        }
      }
      return null;
    },
  };
 }

 ns.start();