/**
 * @license
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
(function() {
  'use strict';

  const HIDE_ALERT_TIMEOUT_MS = 5000;
  const CHECK_SIGN_IN_INTERVAL_MS = 60 * 1000;
  const STALE_CREDENTIAL_THRESHOLD_MS = 10 * 60 * 1000;
  const SIGN_IN_WIDTH_PX = 690;
  const SIGN_IN_HEIGHT_PX = 500;
  const TOO_MANY_FILES = 'too many files to find conflicts';
  const AUTHENTICATION_REQUIRED = 'Authentication required\n';

  /**
    * @appliesMixin Gerrit.BaseUrlMixin
    * @appliesMixin Gerrit.FireMixin
    */
  class GrErrorManager extends Polymer.mixinBehaviors( [
    Gerrit.BaseUrlBehavior,
    Gerrit.FireBehavior,
  ], Polymer.GestureEventListeners(
      Polymer.LegacyElementMixin(
          Polymer.Element))) {
    static get is() { return 'gr-error-manager'; }

    static get properties() {
      return {
      /**
       * The ID of the account that was logged in when the app was launched. If
       * not set, then there was no account at launch.
       */
        knownAccountId: Number,

        /** @type {?Object} */
        _alertElement: Object,
        /** @type {?number} */
        _hideAlertHandle: Number,
        _refreshingCredentials: {
          type: Boolean,
          value: false,
        },

        /**
       * The time (in milliseconds) since the most recent credential check.
       */
        _lastCredentialCheck: {
          type: Number,
          value() { return Date.now(); },
        },
      };
    }

    attached() {
      super.attached();
      this.listen(document, 'server-error', '_handleServerError');
      this.listen(document, 'network-error', '_handleNetworkError');
      this.listen(document, 'auth-error', '_handleAuthError');
      this.listen(document, 'show-alert', '_handleShowAlert');
      this.listen(document, 'show-error', '_handleShowErrorDialog');
      this.listen(document, 'visibilitychange', '_handleVisibilityChange');
      this.listen(document, 'show-auth-required', '_handleAuthRequired');
    }

    detached() {
      super.detached();
      this._clearHideAlertHandle();
      this.unlisten(document, 'server-error', '_handleServerError');
      this.unlisten(document, 'network-error', '_handleNetworkError');
      this.unlisten(document, 'auth-error', '_handleAuthError');
      this.unlisten(document, 'show-auth-required', '_handleAuthRequired');
      this.unlisten(document, 'visibilitychange', '_handleVisibilityChange');
      this.unlisten(document, 'show-error', '_handleShowErrorDialog');
    }

    _shouldSuppressError(msg) {
      return msg.includes(TOO_MANY_FILES);
    }

    _handleAuthRequired() {
      this._showAuthErrorAlert(
          'Log in is required to perform that action.', 'Log in.');
    }

    _handleAuthError() {
      this._showAuthErrorAlert('Auth error', 'Refresh credentials.');
    }

    _handleServerError(e) {
      const {request, response} = e.detail;
      Promise.all([response.text(), this._getLoggedIn()])
          .then(([errorText, loggedIn]) => {
            const url = request && (request.anonymizedUrl || request.url);
            const {status, statusText} = response;
            if (response.status === 403 &&
                loggedIn &&
                errorText === AUTHENTICATION_REQUIRED) {
              // The app was logged at one point and is now getting auth errors.
              // This indicates the auth token is no longer valid.
              this._handleAuthError();
            } else if (!this._shouldSuppressError(errorText)) {
              this._showErrorDialog(this._constructServerErrorMsg({
                status,
                statusText,
                errorText,
                url,
              }));
            }
            console.error(errorText);
          });
    }

    _constructServerErrorMsg({errorText, status, statusText, url}) {
      let err = `Error ${status}`;
      if (statusText) { err += ` (${statusText})`; }
      if (errorText || url) { err += ': '; }
      if (errorText) { err += errorText; }
      if (url) { err += `\nEndpoint: ${url}`; }
      return err;
    }

    _handleShowAlert(e) {
      this._showAlert(e.detail.message, e.detail.action, e.detail.callback,
          e.detail.dismissOnNavigation);
    }

    _handleNetworkError(e) {
      this._showAlert('Server unavailable');
      console.error(e.detail.error.message);
    }

    _getLoggedIn() {
      return this.$.restAPI.getLoggedIn();
    }

    /**
     * @param {string} text
     * @param {?string=} opt_actionText
     * @param {?Function=} opt_actionCallback
     * @param {?boolean=} opt_dismissOnNavigation
     */
    _showAlert(text, opt_actionText, opt_actionCallback,
        opt_dismissOnNavigation) {
      if (this._alertElement) {
        this._hideAlert();
      }

      this._clearHideAlertHandle();
      if (opt_dismissOnNavigation) {
        // Persist alert until navigation.
        this.listen(document, 'location-change', '_hideAlert');
      } else {
        this._hideAlertHandle =
          this.async(this._hideAlert, HIDE_ALERT_TIMEOUT_MS);
      }
      const el = this._createToastAlert();
      el.show(text, opt_actionText, opt_actionCallback);
      this._alertElement = el;
    }

    _hideAlert() {
      if (!this._alertElement) { return; }

      this._alertElement.hide();
      this._alertElement = null;

      // Remove listener for page navigation, if it exists.
      this.unlisten(document, 'location-change', '_hideAlert');
    }

    _clearHideAlertHandle() {
      if (this._hideAlertHandle != null) {
        this.cancelAsync(this._hideAlertHandle);
        this._hideAlertHandle = null;
      }
    }

    _showAuthErrorAlert(errorText, actionText) {
      // TODO(viktard): close alert if it's not for auth error.
      if (this._alertElement) { return; }

      this._alertElement = this._createToastAlert();
      this._alertElement.show(errorText, actionText,
          this._createLoginPopup.bind(this));

      this._refreshingCredentials = true;
      this._requestCheckLoggedIn();
      if (!document.hidden) {
        this._handleVisibilityChange();
      }
    }

    _createToastAlert() {
      const el = document.createElement('gr-alert');
      el.toast = true;
      return el;
    }

    _handleVisibilityChange() {
      // Ignore when the page is transitioning to hidden (or hidden is
      // undefined).
      if (document.hidden !== false) { return; }

      // If not currently refreshing credentials and the credentials are old,
      // request them to confirm their validity or (display an auth toast if it
      // fails).
      const timeSinceLastCheck = Date.now() - this._lastCredentialCheck;
      if (!this._refreshingCredentials &&
          this.knownAccountId !== undefined &&
          timeSinceLastCheck > STALE_CREDENTIAL_THRESHOLD_MS) {
        this._lastCredentialCheck = Date.now();
        this.$.restAPI.checkCredentials();
      }
    }

    _requestCheckLoggedIn() {
      this.debounce(
          'checkLoggedIn', this._checkSignedIn, CHECK_SIGN_IN_INTERVAL_MS);
    }

    _checkSignedIn() {
      this.$.restAPI.checkCredentials().then(account => {
        const isLoggedIn = !!account;
        this._lastCredentialCheck = Date.now();
        if (this._refreshingCredentials) {
          if (isLoggedIn) {
            // If the credentials were refreshed but the account is different
            // then reload the page completely.
            if (account._account_id !== this.knownAccountId) {
              this._reloadPage();
              return;
            }

            this._handleCredentialRefreshed();
          } else {
            this._requestCheckLoggedIn();
          }
        }
      });
    }

    _reloadPage() {
      window.location.reload();
    }

    _createLoginPopup() {
      const left = window.screenLeft +
          (window.outerWidth - SIGN_IN_WIDTH_PX) / 2;
      const top = window.screenTop +
          (window.outerHeight - SIGN_IN_HEIGHT_PX) / 2;
      const options = [
        'width=' + SIGN_IN_WIDTH_PX,
        'height=' + SIGN_IN_HEIGHT_PX,
        'left=' + left,
        'top=' + top,
      ];
      window.open(this.getBaseUrl() +
          '/login/%3FcloseAfterLogin', '_blank', options.join(','));
      this.listen(window, 'focus', '_handleWindowFocus');
    }

    _handleCredentialRefreshed() {
      this.unlisten(window, 'focus', '_handleWindowFocus');
      this._refreshingCredentials = false;
      this._hideAlert();
      this._showAlert('Credentials refreshed.');
    }

    _handleWindowFocus() {
      this.flushDebouncer('checkLoggedIn');
    }

    _handleShowErrorDialog(e) {
      this._showErrorDialog(e.detail.message);
    }

    _handleDismissErrorDialog() {
      this.$.errorOverlay.close();
    }

    _showErrorDialog(message) {
      this.$.reporting.reportErrorDialog(message);
      this.$.errorDialog.text = message;
      this.$.errorOverlay.open();
    }
  }

  customElements.define(GrErrorManager.is, GrErrorManager);
})();