/* 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/. */

// Constants

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

const DIALOG_URL_APP_CHOOSER =
  "chrome://mozapps/content/handling/appChooser.xhtml";
const DIALOG_URL_PERMISSION =
  "chrome://mozapps/content/handling/permissionDialog.xhtml";

var EXPORTED_SYMBOLS = [
  "nsContentDispatchChooser",
  "ContentDispatchChooserTelemetry",
];

const gPrefs = {};
XPCOMUtils.defineLazyPreferenceGetter(
  gPrefs,
  "promptForExternal",
  "network.protocol-handler.prompt-from-external",
  true
);

const PROTOCOL_HANDLER_OPEN_PERM_KEY = "open-protocol-handler";
const PERMISSION_KEY_DELIMITER = "^";

let ContentDispatchChooserTelemetry = {
  /**
   * Maps protocol scheme to telemetry label.
   */
  SCHEME_TO_LABEL: {
    bingmaps: "BING",
    bingweather: "BING",
    fb: "FACEBOOK",
    fbmessenger: "FACEBOOK",
    findmy: "APPLE_FINDMY",
    findmyfriends: "APPLE_FINDMY",
    fmf1: "APPLE_FINDMY",
    fmip1: "APPLE_FINDMY",
    git: "GIT",
    "git-client": "GIT",
    grenada: "APPLE_FINDMY",
    ichat: "IMESSAGE",
    im: "INSTANT_MESSAGE",
    imessage: "IMESSAGE",
    ipp: "IPP",
    ipps: "IPP",
    irc: "IRC",
    irc6: "IRC",
    ircs: "IRC",
    itals: "APPLE_LIVESTREAM",
    italss: "APPLE_LIVESTREAM",
    itls: "APPLE_LIVESTREAM",
    itlss: "APPLE_LIVESTREAM",
    itms: "APPLE_MUSIC",
    itmss: "APPLE_MUSIC",
    itsradio: "APPLE_MUSIC",
    itunes: "APPLE_MUSIC",
    itunesradio: "APPLE_MUSIC",
    itvls: "APPLE_LIVESTREAM",
    itvlss: "APPLE_LIVESTREAM",
    macappstore: "MACAPPSTORE",
    macappstores: "MACAPPSTORE",
    map: "MAP",
    mapitem: "MAP",
    maps: "MAP",
    message: "MESSAGE",
    messages: "MESSAGE",
    microsoftmusic: "MICROSOFT_APP",
    microsoftvideo: "MICROSOFT_APP",
    mswindowsmusic: "MICROSOFT_APP",
    music: "MUSIC",
    musics: "MUSIC",
    onenote: "ONENOTE",
    "onenote-cmd": "ONENOTE",
    pcast: "PODCAST",
    podcast: "PODCAST",
    podcasts: "PODCAST",
    "roblox-player": "ROBLOX",
    search: "SEARCH",
    "search-ms": "SEARCH",
    sip: "SIP",
    sips: "SIP",
    skype: "SKYPE",
    "skype-meetnow": "SKYPE",
    skypewin: "SKYPE",
    tg: "TELEGRAM",
    tv: "TELEVISION",
    zoommtg: "ZOOM",
    zoompbx: "ZOOM",
    zoomus: "ZOOM",
    zune: "MICROSOFT_APP",
  },

  /**
   * Maps protocol scheme prefix to telemetry label.
   */
  SCHEME_PREFIX_TO_LABEL: {
    apple: "APPLE",
    "com.microsoft": "MICROSOFT_APP",
    facetime: "FACETIME",
    "fb-messenger": "FACEBOOK",
    icloud: "ICLOUD",
    "itms-": "APPLE_MUSIC",
    microsoft: "MICROSOFT_APP",
    "ms-": "MICROSOFT_APP",
    outlook: "OUTLOOK",
    photos: "PHOTOS",
    "web+": "WEBHANDLER",
    windows: "WINDOWS_PREFIX",
    "x-apple": "APPLE",
    xbox: "XBOX",
  },

  /**
   * Sandbox flags for telemetry
   * Copied from nsSandboxFlags.h
   */
  SANDBOXED_AUXILIARY_NAVIGATION: 0x2,
  SANDBOXED_TOPLEVEL_NAVIGATION: 0x4,
  SANDBOXED_TOPLEVEL_NAVIGATION_USER_ACTIVATION: 0x20000,

  /**
   * Lazy getter for labels of the external protocol navigation telemetry probe.
   * @returns {string[]} - An array of histogram labels.
   */
  get _telemetryLabels() {
    if (!this._telemetryLabelArray) {
      this._telemetryLabelArray = Services.telemetry.getCategoricalLabels().EXTERNAL_PROTOCOL_HANDLER_DIALOG_CONTEXT_SCHEME;
    }
    return this._telemetryLabelArray;
  },

  /**
   * Get histogram label by protocol scheme.
   * @param {string} aScheme - Protocol scheme to map to histogram label.
   * @returns {string} - Label.
   */
  _getTelemetryLabel(aScheme) {
    if (!aScheme) {
      throw new Error("Invalid scheme");
    }
    let labels = this._telemetryLabels;

    // Custom scheme-to-label mappings
    let mappedLabel = this.SCHEME_TO_LABEL[aScheme];
    if (mappedLabel) {
      return mappedLabel;
    }

    // Prefix mappings
    for (let prefix of Object.keys(this.SCHEME_PREFIX_TO_LABEL)) {
      if (aScheme.startsWith(prefix)) {
        return this.SCHEME_PREFIX_TO_LABEL[prefix];
      }
    }

    // Test if we have a label for the protocol scheme.
    // If not, we use the "OTHER" label.
    if (labels.includes(aScheme)) {
      return aScheme;
    }

    return "OTHER";
  },

  /**
   * Determine if a load was triggered from toplevel or an iframe
   * (cross origin, same origin, sandboxed).
   *
   * @param {BrowsingContext} [aBrowsingContext] - Context of the load.
   * @param {nsIPrincipal} [aTriggeringPrincipal] - Principal which triggered
   * the load.
   * @returns {string} - Histogram key. May return "UNKNOWN".
   */
  _getTelemetryKey(aBrowsingContext, aTriggeringPrincipal) {
    if (!aBrowsingContext) {
      return "UNKNOWN";
    }
    if (aBrowsingContext.top == aBrowsingContext) {
      return "TOPLEVEL";
    }

    let { sandboxFlags } = aBrowsingContext;
    if (sandboxFlags) {
      // Iframe is sandboxed. Determine whether it sets allow flags relevant
      // for the external protocol navigation.
      if (
        !(sandboxFlags & this.SANDBOXED_TOPLEVEL_NAVIGATION) ||
        !(sandboxFlags & this.SANDBOXED_TOPLEVEL_NAVIGATION_USER_ACTIVATION) ||
        !(sandboxFlags & this.SANDBOXED_AUXILIARY_NAVIGATION)
      ) {
        return "SUB_SANDBOX_ALLOW";
      }
      return "SUB_SANDBOX_NOALLOW";
    }

    // We're in a frame, check if the frame is cross origin with the top context.
    if (!aTriggeringPrincipal) {
      return "UNKNOWN";
    }

    let topLevelPrincipal =
      aBrowsingContext.top.embedderElement?.contentPrincipal;
    if (!topLevelPrincipal) {
      return "UNKNOWN";
    }

    if (topLevelPrincipal.isThirdPartyPrincipal(aTriggeringPrincipal)) {
      return "SUB_CROSSORIGIN";
    }

    return "SUB_SAMEORIGIN";
  },

  /**
   * Record telemetry for the external protocol handler dialog.
   * @param {string} aScheme - Scheme of the protocol being loaded.
   * @param {BrowsingContext} [aBrowsingContext] - Context of the load.
   * @param {nsIPrincipal} [aTriggeringPrincipal] - Principal which triggered
   * the load.
   */
  recordTelemetry(aScheme, aBrowsingContext, aTriggeringPrincipal) {
    let type = this._getTelemetryKey(aBrowsingContext, aTriggeringPrincipal);
    let label = this._getTelemetryLabel(aScheme);

    Services.telemetry
      .getKeyedHistogramById("EXTERNAL_PROTOCOL_HANDLER_DIALOG_CONTEXT_SCHEME")
      .add(type, label);
  },
};

class nsContentDispatchChooser {
  /**
   * Prompt the user to open an external application.
   * If the triggering principal doesn't have permission to open apps for the
   * protocol of aURI, we show a permission prompt first.
   * If the caller has permission and a preferred handler is set, we skip the
   * dialogs and directly open the handler.
   * @param {nsIHandlerInfo} aHandler - Info about protocol and handlers.
   * @param {nsIURI} aURI - URI to be handled.
   * @param {nsIPrincipal} [aPrincipal] - Principal which triggered the load.
   * @param {BrowsingContext} [aBrowsingContext] - Context of the load.
   * @param {bool} [aTriggeredExternally] - Whether the load came from outside
   * this application.
   */
  async handleURI(
    aHandler,
    aURI,
    aPrincipal,
    aBrowsingContext,
    aTriggeredExternally = false
  ) {
    let callerHasPermission = this._hasProtocolHandlerPermission(
      aHandler.type,
      aPrincipal
    );

    // Force showing the dialog for links passed from outside the application.
    // This avoids infinite loops, see bug 1678255, bug 1667468, etc.
    if (
      aTriggeredExternally &&
      gPrefs.promptForExternal &&
      // ... unless we intend to open the link with a website or extension:
      !(
        aHandler.preferredAction == Ci.nsIHandlerInfo.useHelperApp &&
        aHandler.preferredApplicationHandler instanceof Ci.nsIWebHandlerApp
      )
    ) {
      aHandler.alwaysAskBeforeHandling = true;
    }

    // Skip the dialog if a preferred application is set and the caller has
    // permission.
    if (
      callerHasPermission &&
      !aHandler.alwaysAskBeforeHandling &&
      (aHandler.preferredAction == Ci.nsIHandlerInfo.useHelperApp ||
        aHandler.preferredAction == Ci.nsIHandlerInfo.useSystemDefault)
    ) {
      try {
        aHandler.launchWithURI(aURI, aBrowsingContext);
      } catch (error) {
        // We are not supposed to ask, but when file not found the user most likely
        // uninstalled the application which handles the uri so we will continue
        // by application chooser dialog.
        if (error.result == Cr.NS_ERROR_FILE_NOT_FOUND) {
          aHandler.alwaysAskBeforeHandling = true;
        } else {
          throw error;
        }
      }
    }

    // We will show a prompt, record telemetry.
    try {
      ContentDispatchChooserTelemetry.recordTelemetry(
        aHandler.type,
        aBrowsingContext,
        aPrincipal
      );
    } catch (error) {
      Cu.reportError(error);
    }

    let shouldOpenHandler = false;
    try {
      shouldOpenHandler = await this._prompt(
        aHandler,
        aPrincipal,
        callerHasPermission,
        aBrowsingContext
      );
    } catch (error) {
      Cu.reportError(error.message);
    }

    if (!shouldOpenHandler) {
      return;
    }

    // Site was granted permission and user chose to open application.
    // Launch the external handler.
    aHandler.launchWithURI(aURI, aBrowsingContext);
  }

  /**
   * Get the name of the application set to handle the the protocol.
   * @param {nsIHandlerInfo} aHandler - Info about protocol and handlers.
   * @returns {string|null} - Human readable handler name or null if the user
   * is expected to set a handler.
   */
  _getHandlerName(aHandler) {
    if (aHandler.alwaysAskBeforeHandling) {
      return null;
    }
    if (
      aHandler.preferredAction == Ci.nsIHandlerInfo.useSystemDefault &&
      aHandler.hasDefaultHandler
    ) {
      return aHandler.defaultDescription;
    }
    return aHandler.preferredApplicationHandler?.name;
  }

  /**
   * Show permission or/and app chooser prompt.
   * @param {nsIHandlerInfo} aHandler - Info about protocol and handlers.
   * @param {nsIPrincipal} aPrincipal - Principal which triggered the load.
   * @param {boolean} aHasPermission - Whether the caller has permission to
   * open the protocol.
   * @param {BrowsingContext} [aBrowsingContext] - Context associated with the
   * protocol navigation.
   */
  async _prompt(aHandler, aPrincipal, aHasPermission, aBrowsingContext) {
    let shouldOpenHandler = false;
    let resetHandlerChoice = false;

    // If caller does not have permission, prompt the user.
    if (!aHasPermission) {
      let canPersistPermission = this._isSupportedPrincipal(aPrincipal);

      let outArgs = Cc["@mozilla.org/hash-property-bag;1"].createInstance(
        Ci.nsIWritablePropertyBag
      );
      // Whether the permission request was granted
      outArgs.setProperty("granted", false);
      // If the user wants to select a new application for the protocol.
      // This will cause us to show the chooser dialog, even if an app is set.
      outArgs.setProperty("resetHandlerChoice", null);
      // If the we should store the permission and not prompt again for it.
      outArgs.setProperty("remember", null);

      await this._openDialog(
        DIALOG_URL_PERMISSION,
        {
          handler: aHandler,
          principal: aPrincipal,
          browsingContext: aBrowsingContext,
          outArgs,
          canPersistPermission,
          preferredHandlerName: this._getHandlerName(aHandler),
        },
        aBrowsingContext
      );
      if (!outArgs.getProperty("granted")) {
        // User denied request
        return false;
      }

      // Check if user wants to set a new application to handle the protocol.
      resetHandlerChoice = outArgs.getProperty("resetHandlerChoice");

      // If the user wants to select a new app we don't persist the permission.
      if (!resetHandlerChoice && aPrincipal) {
        let remember = outArgs.getProperty("remember");
        this._updatePermission(aPrincipal, aHandler.type, remember);
      }

      shouldOpenHandler = true;
    }

    // Prompt if the user needs to make a handler choice for the protocol.
    if (aHandler.alwaysAskBeforeHandling || resetHandlerChoice) {
      // User has not set a preferred application to handle this protocol scheme.
      // Open the application chooser dialog
      let outArgs = Cc["@mozilla.org/hash-property-bag;1"].createInstance(
        Ci.nsIWritablePropertyBag
      );
      outArgs.setProperty("openHandler", false);
      outArgs.setProperty("preferredAction", aHandler.preferredAction);
      outArgs.setProperty(
        "preferredApplicationHandler",
        aHandler.preferredApplicationHandler
      );
      outArgs.setProperty(
        "alwaysAskBeforeHandling",
        aHandler.alwaysAskBeforeHandling
      );
      let usePrivateBrowsing = aBrowsingContext?.usePrivateBrowsing;
      await this._openDialog(
        DIALOG_URL_APP_CHOOSER,
        {
          handler: aHandler,
          outArgs,
          usePrivateBrowsing,
          enableButtonDelay: aHasPermission,
        },
        aBrowsingContext
      );

      shouldOpenHandler = outArgs.getProperty("openHandler");

      // If the user accepted the dialog, apply their selection.
      if (shouldOpenHandler) {
        for (let prop of [
          "preferredAction",
          "preferredApplicationHandler",
          "alwaysAskBeforeHandling",
        ]) {
          aHandler[prop] = outArgs.getProperty(prop);
        }

        // Store handler data
        Cc["@mozilla.org/uriloader/handler-service;1"]
          .getService(Ci.nsIHandlerService)
          .store(aHandler);
      }
    }

    return shouldOpenHandler;
  }

  /**
   * Test if a given principal has the open-protocol-handler permission for a
   * specific protocol.
   * @param {string} scheme - Scheme of the protocol.
   * @param {nsIPrincipal} aPrincipal - Principal to test for permission.
   * @returns {boolean} - true if permission is set, false otherwise.
   */
  _hasProtocolHandlerPermission(scheme, aPrincipal) {
    // Permission disabled by pref
    if (!nsContentDispatchChooser.isPermissionEnabled) {
      return true;
    }

    // If a handler is set to open externally by default we skip the dialog.
    if (
      Services.prefs.getBoolPref(
        "network.protocol-handler.external." + scheme,
        false
      )
    ) {
      return true;
    }

    if (!aPrincipal) {
      return false;
    }

    if (aPrincipal.isAddonOrExpandedAddonPrincipal) {
      return true;
    }

    let key = this._getSkipProtoDialogPermissionKey(scheme);
    return (
      Services.perms.testPermissionFromPrincipal(aPrincipal, key) ===
      Services.perms.ALLOW_ACTION
    );
  }

  /**
   * Get open-protocol-handler permission key for a protocol.
   * @param {string} aProtocolScheme - Scheme of the protocol.
   * @returns {string} - Permission key.
   */
  _getSkipProtoDialogPermissionKey(aProtocolScheme) {
    return (
      PROTOCOL_HANDLER_OPEN_PERM_KEY +
      PERMISSION_KEY_DELIMITER +
      aProtocolScheme
    );
  }

  /**
   * Opens a dialog as a SubDialog on tab level.
   * If we don't have a BrowsingContext we will fallback to a standalone window.
   * @param {string} aDialogURL - URL of the dialog to open.
   * @param {Object} aDialogArgs - Arguments passed to the dialog.
   * @param {BrowsingContext} [aBrowsingContext] - BrowsingContext associated
   * with the tab the dialog is associated with.
   */
  async _openDialog(aDialogURL, aDialogArgs, aBrowsingContext) {
    // Make the app chooser dialog resizable
    let resizable = `resizable=${
      aDialogURL == DIALOG_URL_APP_CHOOSER ? "yes" : "no"
    }`;

    if (aBrowsingContext) {
      let window = aBrowsingContext.topChromeWindow;
      if (!window) {
        throw new Error(
          "Can't show external protocol dialog. BrowsingContext has no chrome window associated."
        );
      }

      let { topFrameElement } = aBrowsingContext;
      if (topFrameElement?.tagName != "browser") {
        throw new Error(
          "Can't show external protocol dialog. BrowsingContext has no browser associated."
        );
      }

      let tabDialogBox = window.gBrowser.getTabDialogBox(topFrameElement);
      return tabDialogBox.open(
        aDialogURL,
        {
          features: resizable,
          allowDuplicateDialogs: false,
          keepOpenSameOriginNav: true,
        },
        aDialogArgs
      ).closedPromise;
    }

    // If we don't have a BrowsingContext, we need to show a standalone window.
    let win = Services.ww.openWindow(
      null,
      aDialogURL,
      null,
      `chrome,dialog=yes,centerscreen,${resizable}`,
      aDialogArgs
    );

    // Wait until window is closed.
    return new Promise(resolve => {
      win.addEventListener("unload", function onUnload(event) {
        if (event.target.location != aDialogURL) {
          return;
        }
        win.removeEventListener("unload", onUnload);
        resolve();
      });
    });
  }

  /**
   * Update the open-protocol-handler permission for the site which triggered
   * the dialog. Sites with this permission may skip this dialog.
   * @param {nsIPrincipal} aPrincipal - subject to update the permission for.
   * @param {string} aScheme - Scheme of protocol to allow.
   * @param {boolean} aAllow - Whether to set / unset the permission.
   */
  _updatePermission(aPrincipal, aScheme, aAllow) {
    // If enabled, store open-protocol-handler permission for content principals.
    if (
      !nsContentDispatchChooser.isPermissionEnabled ||
      aPrincipal.isSystemPrincipal ||
      !this._isSupportedPrincipal(aPrincipal)
    ) {
      return;
    }

    let permKey = this._getSkipProtoDialogPermissionKey(aScheme);
    if (aAllow) {
      Services.perms.addFromPrincipal(
        aPrincipal,
        permKey,
        Services.perms.ALLOW_ACTION,
        Services.perms.EXPIRE_NEVER
      );
    } else {
      Services.perms.removeFromPrincipal(aPrincipal, permKey);
    }
  }

  /**
   * Determine if we can use a principal to store permissions.
   * @param {nsIPrincipal} aPrincipal - Principal to test.
   * @returns {boolean} - true if we can store permissions, false otherwise.
   */
  _isSupportedPrincipal(aPrincipal) {
    return (
      aPrincipal &&
      ["http", "https", "moz-extension", "file"].some(scheme =>
        aPrincipal.schemeIs(scheme)
      )
    );
  }
}

nsContentDispatchChooser.prototype.classID = Components.ID(
  "e35d5067-95bc-4029-8432-e8f1e431148d"
);
nsContentDispatchChooser.prototype.QueryInterface = ChromeUtils.generateQI([
  "nsIContentDispatchChooser",
]);

XPCOMUtils.defineLazyPreferenceGetter(
  nsContentDispatchChooser,
  "isPermissionEnabled",
  "security.external_protocol_requires_permission",
  true
);