/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

var EXPORTED_SYMBOLS = ["WebRTCParent"];

const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const { XPCOMUtils } = ChromeUtils.import(
  "resource://gre/modules/XPCOMUtils.jsm"
);

ChromeUtils.defineModuleGetter(
  this,
  "PluralForm",
  "resource://gre/modules/PluralForm.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "PrivateBrowsingUtils",
  "resource://gre/modules/PrivateBrowsingUtils.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "SitePermissions",
  "resource:///modules/SitePermissions.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "webrtcUI",
  "resource:///modules/webrtcUI.jsm"
);

XPCOMUtils.defineLazyGetter(this, "gBrandBundle", function() {
  return Services.strings.createBundle(
    "chrome://branding/locale/brand.properties"
  );
});

XPCOMUtils.defineLazyServiceGetter(
  this,
  "OSPermissions",
  "@mozilla.org/ospermissionrequest;1",
  "nsIOSPermissionRequest"
);

class WebRTCParent extends JSWindowActorParent {
  didDestroy() {
    webrtcUI.forgetStreamsFromBrowserContext(this.browsingContext);
    webrtcUI.activePerms.delete(this.manager.outerWindowId);
  }

  getBrowser() {
    return this.browsingContext.top.embedderElement;
  }

  receiveMessage(aMessage) {
    switch (aMessage.name) {
      case "rtcpeer:Request": {
        let params = Object.freeze(
          Object.assign(
            {
              origin: this.manager.documentPrincipal.origin,
            },
            aMessage.data
          )
        );

        let blockers = Array.from(webrtcUI.peerConnectionBlockers);

        (async function() {
          for (let blocker of blockers) {
            try {
              let result = await blocker(params);
              if (result == "deny") {
                return false;
              }
            } catch (err) {
              Cu.reportError(`error in PeerConnection blocker: ${err.message}`);
            }
          }
          return true;
        })().then(decision => {
          let message;
          if (decision) {
            webrtcUI.emitter.emit("peer-request-allowed", params);
            message = "rtcpeer:Allow";
          } else {
            webrtcUI.emitter.emit("peer-request-blocked", params);
            message = "rtcpeer:Deny";
          }

          this.sendAsyncMessage(message, {
            callID: params.callID,
            windowID: params.windowID,
          });
        });
        break;
      }
      case "rtcpeer:CancelRequest": {
        let params = Object.freeze({
          origin: this.manager.documentPrincipal.origin,
          callID: aMessage.data,
        });
        webrtcUI.emitter.emit("peer-request-cancel", params);
        break;
      }
      case "webrtc:Request": {
        let data = aMessage.data;

        // Record third party origins for telemetry.
        let isThirdPartyOrigin =
          this.manager.documentPrincipal.origin !=
          this.browsingContext.top.currentWindowGlobal.documentPrincipal.origin;
        data.isThirdPartyOrigin = isThirdPartyOrigin;

        data.origin = data.shouldDelegatePermission
          ? this.browsingContext.top.currentWindowGlobal.documentPrincipal
              .origin
          : this.manager.documentPrincipal.origin;

        let browser = this.getBrowser();
        if (browser.fxrPermissionPrompt) {
          // For Firefox Reality on Desktop, switch to a different mechanism to
          // prompt the user since fewer permissions are available and since many
          // UI dependencies are not available.
          browser.fxrPermissionPrompt(data);
        } else {
          prompt(this, this.getBrowser(), data);
        }
        break;
      }
      case "webrtc:StopRecording":
        this.stopRecording(aMessage.data);
        break;
      case "webrtc:CancelRequest": {
        let browser = this.getBrowser();
        // browser can be null when closing the window
        if (browser) {
          removePrompt(browser, aMessage.data);
        }
        break;
      }
      case "webrtc:UpdateIndicators":
        aMessage.data.documentURI = this.manager.documentURI?.spec;
        if (aMessage.data.windowId) {
          webrtcUI.streamAddedOrRemoved(this.browsingContext, aMessage.data);
        }

        this.updateIndicators(aMessage.data);
        break;
    }
  }

  updateIndicators(aData) {
    let browsingContext = this.browsingContext;
    let state = webrtcUI.updateIndicators(browsingContext.top);

    let browser = this.getBrowser();
    if (!browser) {
      return;
    }

    state.browsingContext = browsingContext;
    state.windowId = aData.windowId;

    let tabbrowser = browser.ownerGlobal.gBrowser;
    if (tabbrowser) {
      tabbrowser.updateBrowserSharing(browser, {
        webRTC: state,
      });
    }
  }

  denyRequest(aRequest) {
    this.sendAsyncMessage("webrtc:Deny", {
      callID: aRequest.callID,
      windowID: aRequest.windowID,
    });
  }

  //
  // Deny the request because the browser does not have access to the
  // camera or microphone due to OS security restrictions. The user may
  // have granted camera/microphone access to the site, but not have
  // allowed the browser access in OS settings.
  //
  denyRequestNoPermission(aRequest) {
    this.sendAsyncMessage("webrtc:Deny", {
      callID: aRequest.callID,
      windowID: aRequest.windowID,
      noOSPermission: true,
    });
  }

  //
  // Check if we have permission to access the camera or screen-sharing and/or
  // microphone at the OS level. Triggers a request to access the device if access
  // is needed and the permission state has not yet been determined.
  //
  async checkOSPermission(camNeeded, micNeeded, scrNeeded) {
    // Don't trigger OS permission requests for fake devices. Fake devices don't
    // require OS permission and the dialogs are problematic in automated testing
    // (where fake devices are used) because they require user interaction.
    if (
      !scrNeeded &&
      Services.prefs.getBoolPref("media.navigator.streams.fake", false)
    ) {
      return true;
    }
    let camStatus = {},
      micStatus = {};
    if (camNeeded || micNeeded) {
      OSPermissions.getMediaCapturePermissionState(camStatus, micStatus);
    }
    if (camNeeded) {
      let camPermission = camStatus.value;
      let camAccessible = await this.checkAndGetOSPermission(
        camPermission,
        OSPermissions.requestVideoCapturePermission
      );
      if (!camAccessible) {
        return false;
      }
    }
    if (micNeeded) {
      let micPermission = micStatus.value;
      let micAccessible = await this.checkAndGetOSPermission(
        micPermission,
        OSPermissions.requestAudioCapturePermission
      );
      if (!micAccessible) {
        return false;
      }
    }
    let scrStatus = {};
    if (scrNeeded) {
      OSPermissions.getScreenCapturePermissionState(scrStatus);
      if (scrStatus.value == OSPermissions.PERMISSION_STATE_DENIED) {
        OSPermissions.maybeRequestScreenCapturePermission();
        return false;
      }
    }
    return true;
  }

  //
  // Given a device's permission, return true if the device is accessible. If
  // the device's permission is not yet determined, request access to the device.
  // |requestPermissionFunc| must return a promise that resolves with true
  // if the device is accessible and false otherwise.
  //
  async checkAndGetOSPermission(devicePermission, requestPermissionFunc) {
    if (
      devicePermission == OSPermissions.PERMISSION_STATE_DENIED ||
      devicePermission == OSPermissions.PERMISSION_STATE_RESTRICTED
    ) {
      return false;
    }
    if (devicePermission == OSPermissions.PERMISSION_STATE_NOTDETERMINED) {
      let deviceAllowed = await requestPermissionFunc();
      if (!deviceAllowed) {
        return false;
      }
    }
    return true;
  }

  stopRecording(aRequest) {
    let outerWindowID = this.manager.outerWindowId;

    if (!webrtcUI.activePerms.has(outerWindowID)) {
      return;
    }

    if (!aRequest.rawID) {
      webrtcUI.activePerms.delete(outerWindowID);
    } else {
      let set = webrtcUI.activePerms.get(outerWindowID);
      set.delete(aRequest.windowID + aRequest.mediaSource + aRequest.rawID);
    }
  }

  /**
   * Checks if the principal has sufficient permissions
   * to fulfill the given request. If the request can be
   * fulfilled, a message is sent to the child
   * signaling that WebRTC permissions were given and
   * this function will return true.
   */
  checkRequestAllowed(aRequest, aPrincipal) {
    if (!aRequest.secure) {
      return false;
    }

    let { audioDevices, videoDevices, sharingScreen } = aRequest;

    let micAllowed =
      SitePermissions.getForPrincipal(aPrincipal, "microphone").state ==
      SitePermissions.ALLOW;
    let camAllowed =
      SitePermissions.getForPrincipal(aPrincipal, "camera").state ==
      SitePermissions.ALLOW;

    let perms = Services.perms;
    let mediaManagerPerm = perms.testExactPermissionFromPrincipal(
      aPrincipal,
      "MediaManagerVideo"
    );
    if (mediaManagerPerm) {
      perms.removeFromPrincipal(aPrincipal, "MediaManagerVideo");
    }

    // Screen sharing shouldn't follow the camera permissions.
    if (videoDevices.length && sharingScreen) {
      camAllowed = false;
    }
    // Don't use persistent permissions from the top-level principal
    // if we're in a cross-origin iframe and permission delegation is not
    // allowed, or when we're handling a potentially insecure third party
    // through a wildcard ("*") allow attribute.
    if (
      (aRequest.isThirdPartyOrigin && !aRequest.shouldDelegatePermission) ||
      aRequest.secondOrigin
    ) {
      camAllowed = false;
      micAllowed = false;
    }

    let activeCamera;
    let activeMic;

    // Always prompt for screen sharing
    if (!sharingScreen) {
      for (let device of videoDevices) {
        let set = webrtcUI.activePerms.get(this.manager.outerWindowId);
        if (
          set &&
          set.has(aRequest.windowID + device.mediaSource + device.id)
        ) {
          activeCamera = device;
          break;
        }
      }

      for (let device of audioDevices) {
        let set = webrtcUI.activePerms.get(this.manager.outerWindowId);
        if (
          set &&
          set.has(aRequest.windowID + device.mediaSource + device.id)
        ) {
          activeMic = device;
          break;
        }
      }
    }
    if (
      (!audioDevices.length || micAllowed || activeMic) &&
      (!videoDevices.length || camAllowed || activeCamera)
    ) {
      let allowedDevices = [];
      if (videoDevices.length) {
        allowedDevices.push((activeCamera || videoDevices[0]).deviceIndex);
        Services.perms.addFromPrincipal(
          aPrincipal,
          "MediaManagerVideo",
          Services.perms.ALLOW_ACTION,
          Services.perms.EXPIRE_SESSION
        );
      }
      if (audioDevices.length) {
        allowedDevices.push((activeMic || audioDevices[0]).deviceIndex);
      }

      // Remember on which URIs we found persistent permissions so that we
      // can remove them if the user clicks 'Stop Sharing'. There's no
      // other way for the stop sharing code to know the hostnames of frames
      // using devices until bug 1066082 is fixed.
      let browser = this.getBrowser();
      browser.getDevicePermissionOrigins("webrtc").add(aPrincipal.origin);

      // If sharingScreen, we're requesting screen-sharing, otherwise camera
      let camNeeded = !!videoDevices.length && !sharingScreen;
      let scrNeeded = !!videoDevices.length && sharingScreen;
      let micNeeded = !!audioDevices.length;
      this.checkOSPermission(camNeeded, micNeeded, scrNeeded).then(
        havePermission => {
          if (havePermission) {
            this.sendAsyncMessage("webrtc:Allow", {
              callID: aRequest.callID,
              windowID: aRequest.windowID,
              devices: allowedDevices,
            });
          } else {
            this.denyRequestNoPermission(aRequest);
          }
        }
      );

      return true;
    }

    return false;
  }
}

function prompt(aActor, aBrowser, aRequest) {
  let {
    audioDevices,
    videoDevices,
    sharingScreen,
    sharingAudio,
    requestTypes,
  } = aRequest;

  let principal = Services.scriptSecurityManager.createContentPrincipalFromOrigin(
    aRequest.origin
  );

  // For add-on principals, we immediately check for permission instead
  // of waiting for the notification to focus. This allows for supporting
  // cases such as browserAction popups where no prompt is shown.
  if (principal.addonPolicy) {
    let isPopup = false;
    let isBackground = false;

    for (let view of principal.addonPolicy.extension.views) {
      if (view.viewType == "popup" && view.xulBrowser == aBrowser) {
        isPopup = true;
      }
      if (view.viewType == "background" && view.xulBrowser == aBrowser) {
        isBackground = true;
      }
    }

    // Recording from background pages is considered too sensitive and will
    // always be denied.
    if (isBackground) {
      aActor.denyRequest(aRequest);
      return;
    }

    // If the request comes from a popup, we don't want to show the prompt,
    // but we do want to allow the request if the user previously gave permission.
    if (isPopup) {
      if (!aActor.checkRequestAllowed(aRequest, principal, aBrowser)) {
        aActor.denyRequest(aRequest);
      }
      return;
    }
  }

  // If the user has already denied access once in this tab,
  // deny again without even showing the notification icon.
  if (
    (audioDevices.length &&
      SitePermissions.getForPrincipal(principal, "microphone", aBrowser)
        .state == SitePermissions.BLOCK) ||
    (videoDevices.length &&
      SitePermissions.getForPrincipal(
        principal,
        sharingScreen ? "screen" : "camera",
        aBrowser
      ).state == SitePermissions.BLOCK)
  ) {
    aActor.denyRequest(aRequest);
    return;
  }

  // Tell the browser to refresh the identity block display in case there
  // are expired permission states.
  aBrowser.dispatchEvent(
    new aBrowser.ownerGlobal.CustomEvent("PermissionStateChange")
  );

  let chromeDoc = aBrowser.ownerDocument;
  let stringBundle = chromeDoc.defaultView.gNavigatorBundle;
  let localization = new Localization(
    ["branding/brand.ftl", "browser/browser.ftl"],
    true
  );

  // Mind the order, because for simplicity we're iterating over the list using
  // "includes()". This allows the rotation of string identifiers. We list the
  // full identifiers here so they can be cross-referenced more easily.
  let joinedRequestTypes = requestTypes.join("And");
  let requestMessages;
  if (aRequest.secondOrigin) {
    requestMessages = [
      // Individual request types first.
      "getUserMedia.shareCameraUnsafeDelegation.message",
      "getUserMedia.shareMicrophoneUnsafeDelegations.message",
      "getUserMedia.shareScreenUnsafeDelegation.message",
      "getUserMedia.shareAudioCaptureUnsafeDelegation.message",
      // Combinations of the above request types last.
      "getUserMedia.shareCameraAndMicrophoneUnsafeDelegation.message",
      "getUserMedia.shareCameraAndAudioCaptureUnsafeDelegation.message",
      "getUserMedia.shareScreenAndMicrophoneUnsafeDelegation.message",
      "getUserMedia.shareScreenAndAudioCaptureUnsafeDelegation.message",
    ];
  } else {
    requestMessages = [
      // Individual request types first.
      "getUserMedia.shareCamera2.message",
      "getUserMedia.shareMicrophone2.message",
      "getUserMedia.shareScreen3.message",
      "getUserMedia.shareAudioCapture2.message",
      // Combinations of the above request types last.
      "getUserMedia.shareCameraAndMicrophone2.message",
      "getUserMedia.shareCameraAndAudioCapture2.me ssage",
      "getUserMedia.shareScreenAndMicrophone3.message",
      "getUserMedia.shareScreenAndAudioCapture3.message",
    ];
  }

  let stringId = requestMessages.find(id => id.includes(joinedRequestTypes));
  let message = aRequest.secondOrigin
    ? stringBundle.getFormattedString(stringId, ["<>", "{}"])
    : stringBundle.getFormattedString(stringId, ["<>"]);

  let notification; // Used by action callbacks.
  let mainAction = {
    label: stringBundle.getString("getUserMedia.allow.label"),
    accessKey: stringBundle.getString("getUserMedia.allow.accesskey"),
    // The real callback will be set during the "showing" event. The
    // empty function here is so that PopupNotifications.show doesn't
    // reject the action.
    callback() {},
  };

  let notificationSilencingEnabled = Services.prefs.getBoolPref(
    "privacy.webrtc.allowSilencingNotifications"
  );

  let secondaryActions = [];
  if (notificationSilencingEnabled && sharingScreen) {
    // We want to free up the checkbox at the bottom of the permission
    // panel for the notification silencing option, so we use a
    // different configuration for the permissions panel when
    // notification silencing is enabled.

    // The formatMessagesSync method returns an array of results
    // for each message that was requested, and for the ones with
    // attributes, returns an attributes array with objects like:
    //
    // { name: "someName", value: "somevalue" }
    //
    // For these strings, which use .label and .accesskey attributes,
    // this convertAttributesToObjects function looks at the attributes
    // property of each message, and returns back an array of objects,
    // where each object property is one of the attribute names, and
    // the property value is the attribute value.
    //
    // So, the above example would be converted into:
    //
    // { someName: "someValue" }
    //
    // which is much easier to access and pass along to other things.
    let convertAttributesToObjects = messages => {
      return messages.map(msg => {
        return msg.attributes.reduce((acc, attribute) => {
          acc[attribute.name] = attribute.value;
          return acc;
        }, {});
      });
    };

    let [notNow, never] = convertAttributesToObjects(
      localization.formatMessagesSync([
        { id: "popup-screen-sharing-not-now" },
        { id: "popup-screen-sharing-never" },
      ])
    );

    secondaryActions = [
      {
        label: notNow.label,
        accessKey: notNow.accesskey,
        callback(aState) {
          aActor.denyRequest(aRequest);
          SitePermissions.setForPrincipal(
            principal,
            "screen",
            SitePermissions.BLOCK,
            SitePermissions.SCOPE_TEMPORARY,
            notification.browser
          );
        },
      },
      {
        label: never.label,
        accessKey: never.accesskey,
        callback(aState) {
          aActor.denyRequest(aRequest);
          SitePermissions.setForPrincipal(
            principal,
            "screen",
            SitePermissions.BLOCK,
            SitePermissions.SCOPE_PERSISTENT,
            notification.browser
          );
        },
      },
    ];
  } else {
    secondaryActions = [
      {
        label: stringBundle.getString("getUserMedia.dontAllow.label"),
        accessKey: stringBundle.getString("getUserMedia.dontAllow.accesskey"),
        callback(aState) {
          aActor.denyRequest(aRequest);
          let scope = SitePermissions.SCOPE_TEMPORARY;
          if (aState && aState.checkboxChecked) {
            scope = SitePermissions.SCOPE_PERSISTENT;
          }
          if (audioDevices.length) {
            SitePermissions.setForPrincipal(
              principal,
              "microphone",
              SitePermissions.BLOCK,
              scope,
              notification.browser
            );
          }
          if (videoDevices.length) {
            SitePermissions.setForPrincipal(
              principal,
              sharingScreen ? "screen" : "camera",
              SitePermissions.BLOCK,
              scope,
              notification.browser
            );
          }
        },
      },
    ];
  }

  let productName = gBrandBundle.GetStringFromName("brandShortName");

  let options = {
    name: webrtcUI.getHostOrExtensionName(principal.URI),
    persistent: true,
    hideClose: true,
    eventCallback(aTopic, aNewBrowser, isCancel) {
      if (aTopic == "swapping") {
        return true;
      }

      let doc = this.browser.ownerDocument;

      // Clean-up video streams of screensharing previews.
      if (
        ((aTopic == "dismissed" || aTopic == "removed") &&
          requestTypes.includes("Screen")) ||
        !requestTypes.includes("Screen")
      ) {
        let video = doc.getElementById("webRTC-previewVideo");
        if (video.stream) {
          video.stream.getTracks().forEach(t => t.stop());
          video.stream = null;
          video.src = null;
          doc.getElementById("webRTC-preview").hidden = true;
        }
        let menupopup = doc.getElementById("webRTC-selectWindow-menupopup");
        if (menupopup._commandEventListener) {
          menupopup.removeEventListener(
            "command",
            menupopup._commandEventListener
          );
          menupopup._commandEventListener = null;
        }
      }

      // If the notification has been cancelled (e.g. due to entering full-screen), also cancel the webRTC request
      if (aTopic == "removed" && notification && isCancel) {
        aActor.denyRequest(aRequest);
      }

      if (aTopic != "showing") {
        return false;
      }

      // BLOCK is handled immediately by MediaManager if it has been set
      // persistently in the permission manager. If it has been set on the tab,
      // it is handled synchronously before we add the notification.
      // Handling of ALLOW is delayed until the popupshowing event,
      // to avoid granting permissions automatically to background tabs.
      if (aActor.checkRequestAllowed(aRequest, principal, aBrowser)) {
        this.remove();
        return true;
      }

      function listDevices(menupopup, devices) {
        while (menupopup.lastChild) {
          menupopup.removeChild(menupopup.lastChild);
        }
        // Removing the child nodes of the menupopup doesn't clear the value
        // attribute of the menulist. This can have unfortunate side effects
        // when the list is rebuilt with a different content, so we remove
        // the value attribute and unset the selectedItem explicitly.
        menupopup.parentNode.removeAttribute("value");
        menupopup.parentNode.selectedItem = null;

        for (let device of devices) {
          addDeviceToList(menupopup, device.name, device.deviceIndex);
        }
      }

      function checkDisabledWindowMenuItem() {
        let list = doc.getElementById("webRTC-selectWindow-menulist");
        let item = list.selectedItem;
        let notificationElement = doc.getElementById(
          "webRTC-shareDevices-notification"
        );
        if (!item || item.hasAttribute("disabled")) {
          notificationElement.setAttribute("invalidselection", "true");
        } else {
          notificationElement.removeAttribute("invalidselection");
        }
      }

      function listScreenShareDevices(menupopup, devices) {
        while (menupopup.lastChild) {
          menupopup.removeChild(menupopup.lastChild);
        }

        // Removing the child nodes of the menupopup doesn't clear the value
        // attribute of the menulist. This can have unfortunate side effects
        // when the list is rebuilt with a different content, so we remove
        // the value attribute and unset the selectedItem explicitly.
        menupopup.parentNode.removeAttribute("value");
        menupopup.parentNode.selectedItem = null;

        let label = doc.getElementById("webRTC-selectWindow-label");
        const gumStringId = "getUserMedia.selectWindowOrScreen";
        label.setAttribute(
          "value",
          stringBundle.getString(gumStringId + ".label")
        );
        label.setAttribute(
          "accesskey",
          stringBundle.getString(gumStringId + ".accesskey")
        );

        // "Select a Window or Screen" is the default because we can't and don't
        // want to pick a 'default' window to share (Full screen is "scary").
        addDeviceToList(
          menupopup,
          stringBundle.getString("getUserMedia.pickWindowOrScreen.label"),
          "-1"
        );
        menupopup.appendChild(doc.createXULElement("menuseparator"));

        // Build the list of 'devices'.
        let monitorIndex = 1;
        for (let i = 0; i < devices.length; ++i) {
          let device = devices[i];
          let type = device.mediaSource;
          let name;
          // Building screen list from available screens.
          if (type == "screen") {
            if (device.name == "Primary Monitor") {
              name = stringBundle.getString(
                "getUserMedia.shareEntireScreen.label"
              );
            } else {
              name = stringBundle.getFormattedString(
                "getUserMedia.shareMonitor.label",
                [monitorIndex]
              );
              ++monitorIndex;
            }
          } else {
            name = device.name;
            if (type == "application") {
              // The application names returned by the platform are of the form:
              // <window count>\x1e<application name>
              let sepIndex = name.indexOf("\x1e");
              let count = name.slice(0, sepIndex);
              let sawcStringId =
                "getUserMedia.shareApplicationWindowCount.label";
              name = PluralForm.get(
                parseInt(count),
                stringBundle.getString(sawcStringId)
              )
                .replace("#1", name.slice(sepIndex + 1))
                .replace("#2", count);
            }
          }
          let item = addDeviceToList(menupopup, name, i, type);
          item.deviceId = device.id;
          item.mediaSource = type;
          if (device.scary) {
            item.scary = true;
          }
        }

        // Always re-select the "No <type>" item.
        doc
          .getElementById("webRTC-selectWindow-menulist")
          .removeAttribute("value");
        doc.getElementById("webRTC-all-windows-shared").hidden = true;

        menupopup._commandEventListener = event => {
          checkDisabledWindowMenuItem();
          let video = doc.getElementById("webRTC-previewVideo");
          if (video.stream) {
            video.stream.getTracks().forEach(t => t.stop());
            video.stream = null;
          }

          let type = event.target.mediaSource;
          let deviceId = event.target.deviceId;
          if (deviceId == undefined) {
            doc.getElementById("webRTC-preview").hidden = true;
            video.src = null;
            return;
          }

          let scary = event.target.scary;
          let warning = doc.getElementById("webRTC-previewWarning");
          warning.hidden = !scary;
          let chromeWin = doc.defaultView;
          if (scary) {
            warning.hidden = false;
            let string;
            let bundle = chromeWin.gNavigatorBundle;

            let learnMoreText = bundle.getString(
              "getUserMedia.shareScreen.learnMoreLabel"
            );
            let baseURL = Services.urlFormatter.formatURLPref(
              "app.support.baseURL"
            );

            let learnMore = chromeWin.document.createXULElement("label", {
              is: "text-link",
            });
            learnMore.setAttribute("href", baseURL + "screenshare-safety");
            learnMore.textContent = learnMoreText;

            if (type == "screen") {
              string = bundle.getFormattedString(
                "getUserMedia.shareScreenWarning.message",
                ["<>"]
              );
            } else {
              let brand = doc
                .getElementById("bundle_brand")
                .getString("brandShortName");
              string = bundle.getFormattedString(
                "getUserMedia.shareFirefoxWarning.message",
                [brand, "<>"]
              );
            }

            let [pre, post] = string.split("<>");
            warning.textContent = pre;
            warning.appendChild(learnMore);
            warning.appendChild(chromeWin.document.createTextNode(post));

            // On Catalina, we don't want to blow our chance to show the
            // OS-level helper prompt to enable screen recording if the user
            // intends to reject anyway. OTOH showing it when they click Allow
            // is too late. A happy middle is to show it when the user makes a
            // choice in the picker. This already happens implicitly if the
            // user chooses "Entire desktop", as a side-effect of our preview,
            // we just need to also do it if they choose "Firefox". These are
            // the lone two options when permission is absent on Catalina.
            // Ironically, these are the two sources marked "scary" from a
            // web-sharing perspective, which is why this code resides here.
            // A restart doesn't appear to be necessary in spite of OS wording.
            let scrStatus = {};
            OSPermissions.getScreenCapturePermissionState(scrStatus);
            if (scrStatus.value == OSPermissions.PERMISSION_STATE_DENIED) {
              OSPermissions.maybeRequestScreenCapturePermission();
            }
          }

          let perms = Services.perms;
          let chromePrincipal = Services.scriptSecurityManager.getSystemPrincipal();
          perms.addFromPrincipal(
            chromePrincipal,
            "MediaManagerVideo",
            perms.ALLOW_ACTION,
            perms.EXPIRE_SESSION
          );

          video.deviceId = deviceId;
          let constraints = {
            video: { mediaSource: type, deviceId: { exact: deviceId } },
          };
          chromeWin.navigator.mediaDevices.getUserMedia(constraints).then(
            stream => {
              if (video.deviceId != deviceId) {
                // The user has selected a different device or closed the panel
                // before getUserMedia finished.
                stream.getTracks().forEach(t => t.stop());
                return;
              }
              video.srcObject = stream;
              video.stream = stream;
              doc.getElementById("webRTC-preview").hidden = false;
              video.onloadedmetadata = function(e) {
                video.play();
              };
            },
            err => {
              if (
                err.name == "OverconstrainedError" &&
                err.constraint == "deviceId"
              ) {
                // Window has disappeared since enumeration, which can happen.
                // No preview for you.
                return;
              }
              Cu.reportError(
                `error in preview: ${err.message} ${err.constraint}`
              );
            }
          );
        };
        menupopup.addEventListener("command", menupopup._commandEventListener);
      }

      function addDeviceToList(menupopup, deviceName, deviceIndex, type) {
        let menuitem = doc.createXULElement("menuitem");
        menuitem.setAttribute("value", deviceIndex);
        menuitem.setAttribute("label", deviceName);
        menuitem.setAttribute("tooltiptext", deviceName);
        if (type) {
          menuitem.setAttribute("devicetype", type);
        }

        if (deviceIndex == "-1") {
          menuitem.setAttribute("disabled", true);
        }

        menupopup.appendChild(menuitem);
        return menuitem;
      }

      doc.getElementById("webRTC-selectCamera").hidden =
        !videoDevices.length || sharingScreen;
      doc.getElementById("webRTC-selectWindowOrScreen").hidden =
        !sharingScreen || !videoDevices.length;
      doc.getElementById("webRTC-selectMicrophone").hidden =
        !audioDevices.length || sharingAudio;

      let camMenupopup = doc.getElementById("webRTC-selectCamera-menupopup");
      let windowMenupopup = doc.getElementById("webRTC-selectWindow-menupopup");
      let micMenupopup = doc.getElementById(
        "webRTC-selectMicrophone-menupopup"
      );
      if (sharingScreen) {
        listScreenShareDevices(windowMenupopup, videoDevices);
        checkDisabledWindowMenuItem();
      } else {
        listDevices(camMenupopup, videoDevices);
        doc
          .getElementById("webRTC-shareDevices-notification")
          .removeAttribute("invalidselection");
      }

      if (!sharingAudio) {
        listDevices(micMenupopup, audioDevices);
      }

      this.mainAction.callback = async function(aState) {
        let remember = false;
        let silenceNotifications = false;

        if (notificationSilencingEnabled && sharingScreen) {
          silenceNotifications = aState && aState.checkboxChecked;
        } else {
          remember = aState && aState.checkboxChecked;
        }

        let allowedDevices = [];
        let perms = Services.perms;
        if (videoDevices.length) {
          let listId =
            "webRTC-select" +
            (sharingScreen ? "Window" : "Camera") +
            "-menulist";
          let videoDeviceIndex = doc.getElementById(listId).value;
          let allowVideoDevice = videoDeviceIndex != "-1";
          if (allowVideoDevice) {
            allowedDevices.push(videoDeviceIndex);
            // Session permission will be removed after use
            // (it's really one-shot, not for the entire session)
            perms.addFromPrincipal(
              principal,
              "MediaManagerVideo",
              perms.ALLOW_ACTION,
              perms.EXPIRE_SESSION
            );
            if (!webrtcUI.activePerms.has(aActor.manager.outerWindowId)) {
              webrtcUI.activePerms.set(aActor.manager.outerWindowId, new Set());
            }

            for (let device of videoDevices) {
              if (device.deviceIndex == videoDeviceIndex) {
                webrtcUI.activePerms
                  .get(aActor.manager.outerWindowId)
                  .add(aRequest.windowID + device.mediaSource + device.id);
                break;
              }
            }
            if (remember) {
              SitePermissions.setForPrincipal(
                principal,
                "camera",
                SitePermissions.ALLOW
              );
            }
          }
        }
        if (audioDevices.length) {
          if (!sharingAudio) {
            let audioDeviceIndex = doc.getElementById(
              "webRTC-selectMicrophone-menulist"
            ).value;
            let allowMic = audioDeviceIndex != "-1";
            if (allowMic) {
              allowedDevices.push(audioDeviceIndex);
              if (!webrtcUI.activePerms.has(aActor.manager.outerWindowId)) {
                webrtcUI.activePerms.set(
                  aActor.manager.outerWindowId,
                  new Set()
                );
              }

              for (let device of audioDevices) {
                if (device.deviceIndex == audioDeviceIndex) {
                  webrtcUI.activePerms
                    .get(aActor.manager.outerWindowId)
                    .add(aRequest.windowID + device.mediaSource + device.id);
                  break;
                }
              }
              if (remember) {
                SitePermissions.setForPrincipal(
                  principal,
                  "microphone",
                  SitePermissions.ALLOW
                );
              }
            }
          } else {
            // Only one device possible for audio capture.
            allowedDevices.push(0);
          }
        }

        if (!allowedDevices.length) {
          aActor.denyRequest(aRequest);
          return;
        }

        if (remember) {
          // Remember on which URIs we set persistent permissions so that we
          // can remove them if the user clicks 'Stop Sharing'.
          aBrowser.getDevicePermissionOrigins("webrtc").add(principal.origin);
        }

        let camNeeded = !!videoDevices.length && !sharingScreen;
        let scrNeeded = !!videoDevices.length && sharingScreen;
        let micNeeded = !!audioDevices.length;
        let havePermission = await aActor.checkOSPermission(
          camNeeded,
          micNeeded,
          scrNeeded
        );
        if (!havePermission) {
          aActor.denyRequestNoPermission(aRequest);
          return;
        }

        aActor.sendAsyncMessage("webrtc:Allow", {
          callID: aRequest.callID,
          windowID: aRequest.windowID,
          devices: allowedDevices,
          suppressNotifications: silenceNotifications,
        });
      };

      // If we haven't handled the permission yet, we want to show the doorhanger.
      return false;
    },
  };

  function shouldShowAlwaysRemember() {
    // Don't offer "always remember" action in PB mode
    if (PrivateBrowsingUtils.isBrowserPrivate(aBrowser)) {
      return false;
    }

    // Don't offer "always remember" action in third party with no permission
    // delegation
    if (aRequest.isThirdPartyOrigin && !aRequest.shouldDelegatePermission) {
      return false;
    }

    // Don't offer "always remember" action in maybe unsafe permission
    // delegation
    if (aRequest.shouldDelegatePermission && aRequest.secondOrigin) {
      return false;
    }

    return true;
  }

  if (shouldShowAlwaysRemember()) {
    // Disable the permanent 'Allow' action if the connection isn't secure, or for
    // screen/audio sharing (because we can't guess which window the user wants to
    // share without prompting). Note that we never enter this block for private
    // browsing windows.
    let reasonForNoPermanentAllow = "";
    if (sharingScreen) {
      reasonForNoPermanentAllow =
        "getUserMedia.reasonForNoPermanentAllow.screen3";
    } else if (sharingAudio) {
      reasonForNoPermanentAllow =
        "getUserMedia.reasonForNoPermanentAllow.audio";
    } else if (!aRequest.secure) {
      reasonForNoPermanentAllow =
        "getUserMedia.reasonForNoPermanentAllow.insecure";
    }

    options.checkbox = {
      label: stringBundle.getString("getUserMedia.remember"),
      checked: principal.isAddonOrExpandedAddonPrincipal,
      checkedState: reasonForNoPermanentAllow
        ? {
            disableMainAction: true,
            warningLabel: stringBundle.getFormattedString(
              reasonForNoPermanentAllow,
              [productName]
            ),
          }
        : undefined,
    };
  }

  // If the notification silencing feature is enabled and we're sharing a
  // screen, then the checkbox for the permission panel is what controls
  // notification silencing.
  if (notificationSilencingEnabled && sharingScreen) {
    let [
      silenceNotifications,
      silenceNotificationsWarning,
    ] = localization.formatMessagesSync([
      { id: "popup-silence-notifications-checkbox" },
      { id: "popup-silence-notifications-checkbox-warning" },
    ]);

    options.checkbox = {
      label: silenceNotifications.value,
      checked: false,
      checkedState: {
        disableMainAction: false,
        warningLabel: silenceNotificationsWarning.value,
      },
    };
  }

  let iconType = "Devices";
  if (
    requestTypes.length == 1 &&
    (requestTypes[0] == "Microphone" || requestTypes[0] == "AudioCapture")
  ) {
    iconType = "Microphone";
  }
  if (requestTypes.includes("Screen")) {
    iconType = "Screen";
  }
  let anchorId = "webRTC-share" + iconType + "-notification-icon";

  let iconClass = iconType.toLowerCase();
  if (iconClass == "devices") {
    iconClass = "camera";
  }
  options.popupIconClass = iconClass + "-icon";

  if (aRequest.secondOrigin) {
    options.secondName = webrtcUI.getHostOrExtensionName(
      null,
      aRequest.secondOrigin
    );
  }

  notification = chromeDoc.defaultView.PopupNotifications.show(
    aBrowser,
    "webRTC-shareDevices",
    message,
    anchorId,
    mainAction,
    secondaryActions,
    options
  );
  notification.callID = aRequest.callID;

  let schemeHistogram = Services.telemetry.getKeyedHistogramById(
    "PERMISSION_REQUEST_ORIGIN_SCHEME"
  );
  let userInputHistogram = Services.telemetry.getKeyedHistogramById(
    "PERMISSION_REQUEST_HANDLING_USER_INPUT"
  );

  let docURI = aRequest.documentURI;
  let scheme = 0;
  if (docURI.startsWith("https")) {
    scheme = 2;
  } else if (docURI.startsWith("http")) {
    scheme = 1;
  }

  for (let requestType of requestTypes) {
    if (requestType == "AudioCapture") {
      requestType = "Microphone";
    }
    requestType = requestType.toLowerCase();

    schemeHistogram.add(requestType, scheme);
    userInputHistogram.add(requestType, aRequest.isHandlingUserInput);
  }
}

function removePrompt(aBrowser, aCallId) {
  let chromeWin = aBrowser.ownerGlobal;
  let notification = chromeWin.PopupNotifications.getNotification(
    "webRTC-shareDevices",
    aBrowser
  );
  if (notification && notification.callID == aCallId) {
    notification.remove();
  }
}