/* jslint node: true */
'use strict';

//  ENiGMA½
const setClientTheme    = require('./theme.js').setClientTheme;
const clientConnections = require('./client_connections.js').clientConnections;
const StatLog           = require('./stat_log.js');
const logger            = require('./logger.js');
const Events            = require('./events.js');
const Config            = require('./config.js').get;
const {
    Errors,
    ErrorReasons
}                       = require('./enig_error.js');
const UserProps         = require('./user_property.js');
const SysProps          = require('./system_property.js');
const SystemLogKeys     = require('./system_log.js');
const User              = require('./user.js');
const {
    getMessageConferenceByTag,
    getMessageAreaByTag,
    getSuitableMessageConfAndAreaTags,
}                       = require('./message_area.js');
const {
    getFileAreaByTag,
    getDefaultFileAreaTag,
}                       = require('./file_base_area.js');

//  deps
const async             = require('async');
const _                 = require('lodash');
const assert            = require('assert');

exports.userLogin             = userLogin;
exports.recordLogin           = recordLogin;
exports.transformLoginError   = transformLoginError;

function userLogin(client, username, password, options, cb) {
    if(!cb && _.isFunction(options)) {
        cb = options;
        options = {};
    }

    const config = Config();

    if(config.users.badUserNames.includes(username.toLowerCase())) {
        client.log.info( { username, ip : client.remoteAddress }, 'Attempt to login with banned username');

        //  slow down a bit to thwart brute force attacks
        return setTimeout( () => {
            return cb(Errors.BadLogin('Disallowed username', ErrorReasons.NotAllowed));
        }, 2000);
    }

    const authInfo = {
        username,
        password,
    };

    authInfo.type   = options.authType || User.AuthFactor1Types.Password;
    authInfo.pubKey = options.ctx;

    client.user.authenticateFactor1(authInfo, err => {
        if(err) {
            return cb(transformLoginError(err, client, username));
        }

        const user = client.user;

        //  Good login; reset any failed attempts
        delete client.sessionFailedLoginAttempts;

        //
        //  Ensure this user is not already logged in.
        //
        const existingClientConnection = clientConnections.find(cc => {
            return user !== cc.user &&          //  not current connection
                user.userId === cc.user.userId; //  ...but same user
        });

        if(existingClientConnection) {
            client.log.info(
                {
                    existingNodeId  : existingClientConnection.node,
                    username        : user.username,
                    userId          : user.userId
                },
                'Already logged in'
            );

            return cb(Errors.BadLogin(
                `User ${user.username} already logged in.`,
                ErrorReasons.AlreadyLoggedIn
            ));
        }

        //  update client logger with addition of username
        client.log = logger.log.child(
            {
                nodeId      : client.log.fields.nodeId,
                sessionId   : client.log.fields.sessionId,
                username    : user.username,
            }
        );

        client.log.info('Successful login');

        //  User's unique session identifier is the same as the connection itself
        user.sessionId = client.session.uniqueId;   //  convenience

        Events.emit(Events.getSystemEvents().UserLogin, { user } );

        setClientTheme(client, user.properties[UserProps.ThemeId]);

        postLoginPrep(client, err => {
            if(err) {
                return cb(err);
            }

            if(user.authenticated) {
                return recordLogin(client, cb);
            }

            //  recordLogin() must happen after 2FA!
            return cb(null);
        });
    });
}

function postLoginPrep(client, cb) {
    async.series(
        [
            (callback) => {
                //
                //  User may (no longer) have read (view) rights to their current
                //  message, conferences and/or areas. Move them out if so.
                //
                const confTag   = client.user.getProperty(UserProps.MessageConfTag);
                const conf      = getMessageConferenceByTag(confTag) || {};
                const area      = getMessageAreaByTag(client.user.getProperty(UserProps.MessageAreaTag), confTag) || {};

                if(!client.acs.hasMessageConfRead(conf) || !client.acs.hasMessageAreaRead(area)) {
                    //  move them out of both area and possibly conf to something suitable, hopefully.
                    const [newConfTag, newAreaTag] = getSuitableMessageConfAndAreaTags(client);
                    client.user.persistProperties({
                        [ UserProps.MessageConfTag ] : newConfTag,
                        [ UserProps.MessageAreaTag ] : newAreaTag,
                    },
                    err => {
                        return callback(err);
                    });
                } else {
                    return callback(null);
                }
            },
            (callback) => {
                //  Likewise for file areas
                const area = getFileAreaByTag(client.user.getProperty(UserProps.FileAreaTag)) || {};
                if(!client.acs.hasFileAreaRead(area)) {
                    const areaTag = getDefaultFileAreaTag(client) || '';
                    client.user.persistProperty(UserProps.FileAreaTag, areaTag, err => {
                        return callback(err);
                    });
                } else {
                    return callback(null);
                }
            }
        ],
        err => {
            return cb(err);
        }
    );
}

function recordLogin(client, cb) {
    assert(client.user.authenticated);  //  don't get in situations where this isn't true

    const user = client.user;
    async.parallel(
        [
            (callback) => {
                StatLog.incrementNonPersistentSystemStat(SysProps.LoginsToday, 1);
                return StatLog.incrementSystemStat(SysProps.LoginCount, 1, callback);
            },
            (callback) => {
                return StatLog.setUserStat(user, UserProps.LastLoginTs, StatLog.now, callback);
            },
            (callback) => {
                return StatLog.incrementUserStat(user, UserProps.LoginCount, 1, callback);
            },
            (callback) => {
                const loginHistoryMax = Config().statLog.systemEvents.loginHistoryMax;
                const historyItem = JSON.stringify({
                    userId      : user.userId,
                    sessionId   : user.sessionId,
                });

                return StatLog.appendSystemLogEntry(
                    SystemLogKeys.UserLoginHistory,
                    historyItem,
                    loginHistoryMax,
                    StatLog.KeepType.Max,
                    callback
                );
            }
        ],
        err => {
            return cb(err);
        }
    );
}

function transformLoginError(err, client, username) {
    client.sessionFailedLoginAttempts = _.get(client, 'sessionFailedLoginAttempts', 0) + 1;
    const disconnect = Config().users.failedLogin.disconnect;
    if(disconnect > 0 && client.sessionFailedLoginAttempts >= disconnect) {
        err = Errors.BadLogin('To many failed login attempts', ErrorReasons.TooMany);
    }

    client.log.info( { username, ip : client.remoteAddress, reason : err.message }, 'Failed login attempt');
    return err;
}