/* 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/. */

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

/** This little class ensures that redirects maintain an https:// origin */
function RedirectHttpsOnly() {}

RedirectHttpsOnly.prototype = {
  asyncOnChannelRedirect(oldChannel, newChannel, flags, callback) {
    if (newChannel.URI.scheme !== "https") {
      callback.onRedirectVerifyCallback(Cr.NS_ERROR_ABORT);
    } else {
      callback.onRedirectVerifyCallback(Cr.NS_OK);
    }
  },

  getInterface(iid) {
    return this.QueryInterface(iid);
  },
  QueryInterface: ChromeUtils.generateQI(["nsIChannelEventSink"]),
};

/** This class loads a resource into a single string. ResourceLoader.load() is
 * the entry point. */
function ResourceLoader(res, rej) {
  this.resolve = res;
  this.reject = rej;
  this.data = "";
}

/** Loads the identified https:// URL. */
ResourceLoader.load = function (uri, doc) {
  return new Promise((resolve, reject) => {
    let listener = new ResourceLoader(resolve, reject);
    let ioChannel = NetUtil.newChannel({
      uri,
      loadingNode: doc,
      securityFlags: Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
      contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_SCRIPT,
    });

    ioChannel.loadGroup = doc.documentLoadGroup.QueryInterface(Ci.nsILoadGroup);
    ioChannel.notificationCallbacks = new RedirectHttpsOnly();
    ioChannel.asyncOpen(listener);
  });
};

ResourceLoader.prototype = {
  onDataAvailable(request, input, offset, count) {
    let stream = Cc["@mozilla.org/scriptableinputstream;1"].createInstance(
      Ci.nsIScriptableInputStream
    );
    stream.init(input);
    this.data += stream.read(count);
  },

  onStartRequest(request) {},

  onStopRequest(request, status) {
    if (Components.isSuccessCode(status)) {
      var statusCode = request.QueryInterface(Ci.nsIHttpChannel).responseStatus;
      if (statusCode === 200) {
        this.resolve({ request, data: this.data });
      } else {
        this.reject(new Error("Non-200 response from server: " + statusCode));
      }
    } else {
      this.reject(new Error("Load failed: " + status));
    }
  },

  getInterface(iid) {
    return this.QueryInterface(iid);
  },
  QueryInterface: ChromeUtils.generateQI(["nsIStreamListener"]),
};

/**
 * A simple implementation of the WorkerLocation interface.
 */
function createLocationFromURI(uri) {
  return {
    href: uri.spec,
    protocol: uri.scheme + ":",
    host: uri.host + (uri.port >= 0 ? ":" + uri.port : ""),
    port: uri.port,
    hostname: uri.host,
    pathname: uri.pathQueryRef.replace(/[#\?].*/, ""),
    search: uri.pathQueryRef.replace(/^[^\?]*/, "").replace(/#.*/, ""),
    hash: uri.hasRef ? "#" + uri.ref : "",
    origin: uri.prePath,
    toString() {
      return uri.spec;
    },
  };
}

/**
 * A javascript sandbox for running an IdP.
 *
 * @param domain (string) the domain of the IdP
 * @param protocol (string?) the protocol of the IdP [default: 'default']
 * @param win (obj) the current window
 * @throws if the domain or protocol aren't valid
 */
export function IdpSandbox(domain, protocol, win) {
  this.source = IdpSandbox.createIdpUri(domain, protocol || "default");
  this.active = null;
  this.sandbox = null;
  this.window = win;
}

IdpSandbox.checkDomain = function (domain) {
  if (!domain || typeof domain !== "string") {
    throw new Error(
      "Invalid domain for identity provider: " +
        "must be a non-zero length string"
    );
  }
};

/**
 * Checks that the IdP protocol is superficially sane.  In particular, we don't
 * want someone adding relative paths (e.g., '../../myuri'), which could be used
 * to move outside of /.well-known/ and into space that they control.
 */
IdpSandbox.checkProtocol = function (protocol) {
  let message = "Invalid protocol for identity provider: ";
  if (!protocol || typeof protocol !== "string") {
    throw new Error(message + "must be a non-zero length string");
  }
  if (decodeURIComponent(protocol).match(/[\/\\]/)) {
    throw new Error(message + "must not include '/' or '\\'");
  }
};

/**
 * Turns a domain and protocol into a URI.  This does some aggressive checking
 * to make sure that we aren't being fooled somehow.  Throws on fooling.
 */
IdpSandbox.createIdpUri = function (domain, protocol) {
  IdpSandbox.checkDomain(domain);
  IdpSandbox.checkProtocol(protocol);

  let message = "Invalid IdP parameters: ";
  try {
    let wkIdp = "https://" + domain + "/.well-known/idp-proxy/" + protocol;
    let uri = Services.io.newURI(wkIdp);

    if (uri.hostPort !== domain) {
      throw new Error(message + "domain is invalid");
    }
    if (uri.pathQueryRef.indexOf("/.well-known/idp-proxy/") !== 0) {
      throw new Error(message + "must produce a /.well-known/idp-proxy/ URI");
    }

    return uri;
  } catch (e) {
    if (
      typeof e.result !== "undefined" &&
      e.result === Cr.NS_ERROR_MALFORMED_URI
    ) {
      throw new Error(message + "must produce a valid URI");
    }
    throw e;
  }
};

IdpSandbox.prototype = {
  isSame(domain, protocol) {
    return this.source.spec === IdpSandbox.createIdpUri(domain, protocol).spec;
  },

  start() {
    if (!this.active) {
      this.active = ResourceLoader.load(this.source, this.window.document).then(
        result => this._createSandbox(result)
      );
    }
    return this.active;
  },

  // Provides the sandbox with some useful facilities.  Initially, this is only
  // a minimal set; it is far easier to add more as the need arises, than to
  // take them back if we discover a mistake.
  _populateSandbox(uri) {
    this.sandbox.location = Cu.cloneInto(
      createLocationFromURI(uri),
      this.sandbox,
      { cloneFunctions: true }
    );
  },

  _createSandbox(result) {
    let principal = Services.scriptSecurityManager.getChannelResultPrincipal(
      result.request
    );

    this.sandbox = Cu.Sandbox(principal, {
      sandboxName: "IdP-" + this.source.host,
      wantComponents: false,
      wantExportHelpers: false,
      wantGlobalProperties: [
        "indexedDB",
        "XMLHttpRequest",
        "TextEncoder",
        "TextDecoder",
        "URL",
        "URLSearchParams",
        "atob",
        "btoa",
        "Blob",
        "crypto",
        "rtcIdentityProvider",
        "fetch",
      ],
    });
    let registrar = this.sandbox.rtcIdentityProvider;
    if (!Cu.isXrayWrapper(registrar)) {
      throw new Error("IdP setup failed");
    }

    // have to use the ultimate URI, not the starting one to avoid
    // that origin stealing from the one that redirected to it
    this._populateSandbox(result.request.URI);
    try {
      Cu.evalInSandbox(
        result.data,
        this.sandbox,
        "latest",
        result.request.URI.spec,
        1
      );
    } catch (e) {
      // These can be passed straight on, because they are explicitly labelled
      // as being IdP errors by the IdP and we drop line numbers as a result.
      if (e.name === "IdpError" || e.name === "IdpLoginError") {
        throw e;
      }
      this._logError(e);
      throw new Error("Error in IdP, check console for details");
    }

    if (!registrar.hasIdp) {
      throw new Error("IdP failed to call rtcIdentityProvider.register()");
    }
    return registrar;
  },

  // Capture all the details from the error and log them to the console.  This
  // can't rethrow anything else because that could leak information about the
  // internal workings of the IdP across origins.
  _logError(e) {
    let winID = this.window.windowGlobalChild.innerWindowId;
    let scriptError = Cc["@mozilla.org/scripterror;1"].createInstance(
      Ci.nsIScriptError
    );
    scriptError.initWithWindowID(
      e.message,
      e.fileName,
      null,
      e.lineNumber,
      e.columnNumber,
      Ci.nsIScriptError.errorFlag,
      "content javascript",
      winID
    );
    Services.console.logMessage(scriptError);
  },

  stop() {
    if (this.sandbox) {
      Cu.nukeSandbox(this.sandbox);
    }
    this.sandbox = null;
    this.active = null;
  },

  toString() {
    return this.source.spec;
  },
};