/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2017 Vector Creations Ltd
Copyright 2018 New Vector Ltd

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.
*/

import Promise from 'bluebird';
import Matrix from 'matrix-js-sdk';

import MatrixClientPeg from './MatrixClientPeg';
import createMatrixClient from './utils/createMatrixClient';
import Analytics from './Analytics';
import Notifier from './Notifier';
import UserActivity from './UserActivity';
import Presence from './Presence';
import dis from './dispatcher';
import DMRoomMap from './utils/DMRoomMap';
import RtsClient from './RtsClient';
import Modal from './Modal';
import sdk from './index';
import ActiveWidgetStore from './stores/ActiveWidgetStore';
import PlatformPeg from "./PlatformPeg";

/**
 * Called at startup, to attempt to build a logged-in Matrix session. It tries
 * a number of things:
 *
 *
 * 1. if we have a guest access token in the fragment query params, it uses
 *    that.
 *
 * 2. if an access token is stored in local storage (from a previous session),
 *    it uses that.
 *
 * 3. it attempts to auto-register as a guest user.
 *
 * If any of steps 1-4 are successful, it will call {_doSetLoggedIn}, which in
 * turn will raise on_logged_in and will_start_client events.
 *
 * @param {object} opts
 *
 * @param {object} opts.fragmentQueryParams: string->string map of the
 *     query-parameters extracted from the #-fragment of the starting URI.
 *
 * @param {boolean} opts.enableGuest: set to true to enable guest access tokens
 *     and auto-guest registrations.
 *
 * @params {string} opts.guestHsUrl: homeserver URL. Only used if enableGuest is
 *     true; defines the HS to register against.
 *
 * @params {string} opts.guestIsUrl: homeserver URL. Only used if enableGuest is
 *     true; defines the IS to use.
 *
 * @returns {Promise} a promise which resolves when the above process completes.
 *     Resolves to `true` if we ended up starting a session, or `false` if we
 *     failed.
 */
export async function loadSession(opts) {
    try {
        let enableGuest = opts.enableGuest || false;
        const guestHsUrl = opts.guestHsUrl;
        const guestIsUrl = opts.guestIsUrl;
        const fragmentQueryParams = opts.fragmentQueryParams || {};
        const defaultDeviceDisplayName = opts.defaultDeviceDisplayName;

        if (!guestHsUrl) {
            console.warn("Cannot enable guest access: can't determine HS URL to use");
            enableGuest = false;
        }

        if (enableGuest &&
            fragmentQueryParams.guest_user_id &&
            fragmentQueryParams.guest_access_token
           ) {
            console.log("Using guest access credentials");
            return _doSetLoggedIn({
                userId: fragmentQueryParams.guest_user_id,
                accessToken: fragmentQueryParams.guest_access_token,
                homeserverUrl: guestHsUrl,
                identityServerUrl: guestIsUrl,
                guest: true,
            }, true).then(() => true);
        }
        const success = await _restoreFromLocalStorage();
        if (success) {
            return true;
        }

        if (enableGuest) {
            return _registerAsGuest(guestHsUrl, guestIsUrl, defaultDeviceDisplayName);
        }

        // fall back to login screen
        return false;
    } catch (e) {
        return _handleLoadSessionFailure(e);
    }
}

/**
 * @param {Object} queryParams    string->string map of the
 *     query-parameters extracted from the real query-string of the starting
 *     URI.
 *
 * @param {String} defaultDeviceDisplayName
 *
 * @returns {Promise} promise which resolves to true if we completed the token
 *    login, else false
 */
export function attemptTokenLogin(queryParams, defaultDeviceDisplayName) {
    if (!queryParams.loginToken) {
        return Promise.resolve(false);
    }

    if (!queryParams.homeserver) {
        console.warn("Cannot log in with token: can't determine HS URL to use");
        return Promise.resolve(false);
    }

    // create a temporary MatrixClient to do the login
    const client = Matrix.createClient({
        baseUrl: queryParams.homeserver,
    });

    return client.login(
        "m.login.token", {
            token: queryParams.loginToken,
            initial_device_display_name: defaultDeviceDisplayName,
        },
    ).then(function(data) {
        console.log("Logged in with token");
        return _clearStorage().then(() => {
            _persistCredentialsToLocalStorage({
                userId: data.user_id,
                deviceId: data.device_id,
                accessToken: data.access_token,
                homeserverUrl: queryParams.homeserver,
                identityServerUrl: queryParams.identityServer,
                guest: false,
            });
            return true;
        });
    }).catch((err) => {
        console.error("Failed to log in with login token: " + err + " " +
                      err.data);
        return false;
    });
}

export function handleInvalidStoreError(e) {
    if (e.reason === Matrix.InvalidStoreError.TOGGLED_LAZY_LOADING) {
        return Promise.resolve().then(() => {
            const lazyLoadEnabled = e.value;
            if (lazyLoadEnabled) {
                const LazyLoadingResyncDialog =
                    sdk.getComponent("views.dialogs.LazyLoadingResyncDialog");
                return new Promise((resolve) => {
                    Modal.createDialog(LazyLoadingResyncDialog, {
                        onFinished: resolve,
                    });
                });
            } else {
                // show warning about simultaneous use
                // between LL/non-LL version on same host.
                // as disabling LL when previously enabled
                // is a strong indicator of this (/develop & /app)
                const LazyLoadingDisabledDialog =
                    sdk.getComponent("views.dialogs.LazyLoadingDisabledDialog");
                return new Promise((resolve) => {
                    Modal.createDialog(LazyLoadingDisabledDialog, {
                        onFinished: resolve,
                        host: window.location.host,
                    });
                });
            }
        }).then(() => {
            return MatrixClientPeg.get().store.deleteAllData();
        }).then(() => {
            PlatformPeg.get().reload();
        });
    }
}

function _registerAsGuest(hsUrl, isUrl, defaultDeviceDisplayName) {
    console.log(`Doing guest login on ${hsUrl}`);

    // TODO: we should probably de-duplicate this and Login.loginAsGuest.
    // Not really sure where the right home for it is.

    // create a temporary MatrixClient to do the login
    const client = Matrix.createClient({
        baseUrl: hsUrl,
    });

    return client.registerGuest({
        body: {
            initial_device_display_name: defaultDeviceDisplayName,
        },
    }).then((creds) => {
        console.log(`Registered as guest: ${creds.user_id}`);
        return _doSetLoggedIn({
            userId: creds.user_id,
            deviceId: creds.device_id,
            accessToken: creds.access_token,
            homeserverUrl: hsUrl,
            identityServerUrl: isUrl,
            guest: true,
        }, true).then(() => true);
    }, (err) => {
        console.error("Failed to register as guest: " + err + " " + err.data);
        return false;
    });
}

// returns a promise which resolves to true if a session is found in
// localstorage
//
// N.B. Lifecycle.js should not maintain any further localStorage state, we
//      are moving towards using SessionStore to keep track of state related
//      to the current session (which is typically backed by localStorage).
//
//      The plan is to gradually move the localStorage access done here into
//      SessionStore to avoid bugs where the view becomes out-of-sync with
//      localStorage (e.g. teamToken, isGuest etc.)
async function _restoreFromLocalStorage() {
    if (!localStorage) {
        return false;
    }
    const hsUrl = localStorage.getItem("mx_hs_url");
    const isUrl = localStorage.getItem("mx_is_url") || 'https://matrix.org';
    const accessToken = localStorage.getItem("mx_access_token");
    const userId = localStorage.getItem("mx_user_id");
    const deviceId = localStorage.getItem("mx_device_id");

    let isGuest;
    if (localStorage.getItem("mx_is_guest") !== null) {
        isGuest = localStorage.getItem("mx_is_guest") === "true";
    } else {
        // legacy key name
        isGuest = localStorage.getItem("matrix-is-guest") === "true";
    }

    if (accessToken && userId && hsUrl) {
        console.log(`Restoring session for ${userId}`);
        await _doSetLoggedIn({
            userId: userId,
            deviceId: deviceId,
            accessToken: accessToken,
            homeserverUrl: hsUrl,
            identityServerUrl: isUrl,
            guest: isGuest,
        }, false);
        return true;
    } else {
        console.log("No previous session found.");
        return false;
    }
}

function _handleLoadSessionFailure(e) {
    console.log("Unable to load session", e);

    const def = Promise.defer();
    const SessionRestoreErrorDialog =
          sdk.getComponent('views.dialogs.SessionRestoreErrorDialog');

    Modal.createTrackedDialog('Session Restore Error', '', SessionRestoreErrorDialog, {
        error: e.message,
        onFinished: (success) => {
            def.resolve(success);
        },
    });

    return def.promise.then((success) => {
        if (success) {
            // user clicked continue.
            _clearStorage();
            return false;
        }

        // try, try again
        return loadSession();
    });
}

let rtsClient = null;
export function initRtsClient(url) {
    if (url) {
        rtsClient = new RtsClient(url);
    } else {
        rtsClient = null;
    }
}

/**
 * Transitions to a logged-in state using the given credentials.
 *
 * Starts the matrix client and all other react-sdk services that
 * listen for events while a session is logged in.
 *
 * Also stops the old MatrixClient and clears old credentials/etc out of
 * storage before starting the new client.
 *
 * @param {MatrixClientCreds} credentials The credentials to use
 *
 * @returns {Promise} promise which resolves to the new MatrixClient once it has been started
 */
export function setLoggedIn(credentials) {
    stopMatrixClient();
    return _doSetLoggedIn(credentials, true);
}

/**
 * fires on_logging_in, optionally clears localstorage, persists new credentials
 * to localstorage, starts the new client.
 *
 * @param {MatrixClientCreds} credentials
 * @param {Boolean} clearStorage
 *
 * @returns {Promise} promise which resolves to the new MatrixClient once it has been started
 */
async function _doSetLoggedIn(credentials, clearStorage) {
    credentials.guest = Boolean(credentials.guest);

    console.log(
        "setLoggedIn: mxid: " + credentials.userId +
        " deviceId: " + credentials.deviceId +
        " guest: " + credentials.guest +
        " hs: " + credentials.homeserverUrl,
    );

    // This is dispatched to indicate that the user is still in the process of logging in
    // because `teamPromise` may take some time to resolve, breaking the assumption that
    // `setLoggedIn` takes an "instant" to complete, and dispatch `on_logged_in` a few ms
    // later than MatrixChat might assume.
    //
    // we fire it *synchronously* to make sure it fires before on_logged_in.
    // (dis.dispatch uses `setTimeout`, which does not guarantee ordering.)
    dis.dispatch({action: 'on_logging_in'}, true);

    if (clearStorage) {
        await _clearStorage();
    }

    Analytics.setLoggedIn(credentials.guest, credentials.homeserverUrl, credentials.identityServerUrl);

    // Resolves by default
    let teamPromise = Promise.resolve(null);


    if (localStorage) {
        try {
            _persistCredentialsToLocalStorage(credentials);

            // The user registered as a PWLU (PassWord-Less User), the generated password
            // is cached here such that the user can change it at a later time.
            if (credentials.password) {
                // Update SessionStore
                dis.dispatch({
                    action: 'cached_password',
                    cachedPassword: credentials.password,
                });
            }
        } catch (e) {
            console.warn("Error using local storage: can't persist session!", e);
        }

        if (rtsClient && !credentials.guest) {
            teamPromise = rtsClient.login(credentials.userId).then((body) => {
                if (body.team_token) {
                    localStorage.setItem("mx_team_token", body.team_token);
                }
                return body.team_token;
            }, (err) => {
                console.warn(`Failed to get team token on login: ${err}` );
                return null;
            });
        }
    } else {
        console.warn("No local storage available: can't persist session!");
    }

    MatrixClientPeg.replaceUsingCreds(credentials);

    teamPromise.then((teamToken) => {
        dis.dispatch({action: 'on_logged_in', teamToken: teamToken});
    });

    await startMatrixClient();
    return MatrixClientPeg.get();
}

function _persistCredentialsToLocalStorage(credentials) {
    localStorage.setItem("mx_hs_url", credentials.homeserverUrl);
    localStorage.setItem("mx_is_url", credentials.identityServerUrl);
    localStorage.setItem("mx_user_id", credentials.userId);
    localStorage.setItem("mx_access_token", credentials.accessToken);
    localStorage.setItem("mx_is_guest", JSON.stringify(credentials.guest));

    // if we didn't get a deviceId from the login, leave mx_device_id unset,
    // rather than setting it to "undefined".
    //
    // (in this case MatrixClient doesn't bother with the crypto stuff
    // - that's fine for us).
    if (credentials.deviceId) {
        localStorage.setItem("mx_device_id", credentials.deviceId);
    }

    console.log(`Session persisted for ${credentials.userId}`);
}

let _isLoggingOut = false;

/**
 * Logs the current session out and transitions to the logged-out state
 */
export function logout() {
    if (!MatrixClientPeg.get()) return;

    if (MatrixClientPeg.get().isGuest()) {
        // logout doesn't work for guest sessions
        // Also we sometimes want to re-log in a guest session
        // if we abort the login

        // use settimeout to avoid racing with react unmounting components
        // which need a valid matrixclientpeg
        setTimeout(()=>{
            onLoggedOut();
        }, 0);
        return;
    }

    _isLoggingOut = true;
    MatrixClientPeg.get().logout().then(onLoggedOut,
        (err) => {
            // Just throwing an error here is going to be very unhelpful
            // if you're trying to log out because your server's down and
            // you want to log into a different server, so just forget the
            // access token. It's annoying that this will leave the access
            // token still valid, but we should fix this by having access
            // tokens expire (and if you really think you've been compromised,
            // change your password).
            console.log("Failed to call logout API: token will not be invalidated");
            onLoggedOut();
        },
    ).done();
}

export function isLoggingOut() {
    return _isLoggingOut;
}

/**
 * Starts the matrix client and all other react-sdk services that
 * listen for events while a session is logged in.
 */
async function startMatrixClient() {
    console.log(`Lifecycle: Starting MatrixClient`);

    // dispatch this before starting the matrix client: it's used
    // to add listeners for the 'sync' event so otherwise we'd have
    // a race condition (and we need to dispatch synchronously for this
    // to work).
    dis.dispatch({action: 'will_start_client'}, true);

    Notifier.start();
    UserActivity.start();
    Presence.start();
    DMRoomMap.makeShared().start();
    ActiveWidgetStore.start();

    await MatrixClientPeg.start();

    // dispatch that we finished starting up to wire up any other bits
    // of the matrix client that cannot be set prior to starting up.
    dis.dispatch({action: 'client_started'});
}

/*
 * Stops a running client and all related services, and clears persistent
 * storage. Used after a session has been logged out.
 */
export function onLoggedOut() {
    _isLoggingOut = false;
    stopMatrixClient();
    _clearStorage().done();
    dis.dispatch({action: 'on_logged_out'});
}

/**
 * @returns {Promise} promise which resolves once the stores have been cleared
 */
function _clearStorage() {
    Analytics.logout();

    if (window.localStorage) {
        const hsUrl = window.localStorage.getItem("mx_hs_url");
        const isUrl = window.localStorage.getItem("mx_is_url");
        window.localStorage.clear();

        // preserve our HS & IS URLs for convenience
        // N.B. we cache them in hsUrl/isUrl and can't really inline them
        // as getCurrentHsUrl() may call through to localStorage.
        // NB. We do clear the device ID (as well as all the settings)
        if (hsUrl) window.localStorage.setItem("mx_hs_url", hsUrl);
        if (isUrl) window.localStorage.setItem("mx_is_url", isUrl);
    }

    // create a temporary client to clear out the persistent stores.
    const cli = createMatrixClient({
        // we'll never make any requests, so can pass a bogus HS URL
        baseUrl: "",
    });
    return cli.clearStores();
}

/**
 * Stop all the background processes related to the current client.
 */
export function stopMatrixClient() {
    Notifier.stop();
    UserActivity.stop();
    Presence.stop();
    ActiveWidgetStore.stop();
    if (DMRoomMap.shared()) DMRoomMap.shared().stop();
    const cli = MatrixClientPeg.get();
    if (cli) {
        cli.stopClient();
        cli.removeAllListeners();
        MatrixClientPeg.unset();
    }
}