require('dotenv').load();
var Redshift = require('node-redshift');
var SQL = require('sql-template-strings');
var Store = require('jfs');

var sessions_db = new Store('../botkit/lib/storage/sessions');
var users_db = new Store('../botkit/lib/storage/users');

var client = {
    user: process.env.Redshift_user,
    database: process.env.Redshift_database,
    password: process.env.Redshift_password,
    port: process.env.Redshift_port,
    host: process.env.Redshift_host
};

var redshift  = new Redshift(client);

if (!process.env.Redshift_user) {
    console.log('Error: Specify Redshift_user in environment');
    process.exit(1);
}

if (!process.env.Redshift_database) {
    console.log('Error: Specify Redshift_database in environment');
    process.exit(1);
}

if (!process.env.Redshift_password) {
    console.log('Error: Specify Redshift_password in environment');
    process.exit(1);
}

if (!process.env.Redshift_port) {
    console.log('Error: Specify Redshift_port in environment');
    process.exit(1);
}

if (!process.env.Redshift_host) {
    console.log('Error: Specify Redshift_host in environment');
    process.exit(1);
}


var schedule = require('node-schedule');

var rule = new schedule.RecurrenceRule();

rule.second = [0, 15, 30, 45];

function getSessions() {
    return new Promise(function (resolve, reject) {
        sessions_db.all(function (sessions) {
            return resolve(sessions);
        });;
    })
}

function getUsers() {
    return new Promise(function (resolve, reject) {
        users_db.all(function (users) {
            return resolve(users);
        });
    });
}

var j = schedule.scheduleJob(rule, function() {
    var dbSnapshot = {
    }

    return getSessions()
    .then(function(sessions) {
        dbSnapshot.sessions = sessions;
        return getUsers();
    })
    .then(function(users) {
        dbSnapshot.users = users;
        return;
    })
    .then(function() {
        var sessions_list = Object.keys(dbSnapshot.sessions);
        var users_list = Object.keys(dbSnapshot.users);

        var last_sessionIds = [];

        dbSnapshot.users.map(function(user) {
            let last_sessionId = user.last_session;

            // Construct an array with all the last sessions :
            last_sessionIds.push(last_sessionId);

            return _.filter(sessions_list, function(sessionId) {
                // remove ids from all last sessions
                return last_sessionId.indexOf(sessionId) > -1;
            });
        });
    })
    .then(function(sessionsToPushIds) {
        sessionsToPushIds.map(function (sessionId) {
            console.log(`pushing into db session ${sessionId}`;

                var start_time = sessions[sessionId].start_time;
                var user_uuid = sessions[sessionId].userid;
                var messages = sessions[sessionId].messages;

                //ADD redshift push
                redshift.query(SQL`INSERT INTO sessions (id, start_time, userid) VALUES (${sessionId},${start_time}, ${user_uuid})`, {raw: true})
                .then(function() {
                    let batchInsert = "";

                    dbSnapshot.messages.forEach(function(message) {
                        let mess_uuid = message.mess_uuid;
                        let content = message.content;
                        let received_at = message.received_at;
                        let intent = message.intent;
                        let entity = message.entity;
                        let resp_uuid = message.resp_uuid;

                        batchInsert += `(${mess_uuid},${content},${received_at},${resp_uuid},${session_uuid}),`;
                    })

                    batchInsert = batchInsert.slice(0, -1);

                    // TODO add error handling on maximum string size reached
                    redshift.query(SQL`INSERT INTO messages (mess_uuid, content, received_at, resp_uuid, sessionid) VALUES ${batchInsert}`, {raw: true})
                    .then(function(){
                        console.log( messages[message] );
                        return sessionId;
                    })
                    .catch(function(err){
                        console.log(err);
                        return sessionId;
                    });
                })
                .then(function(sessionId) {
                    sessions_db.delete(sessionId);
                });
            });
    });
});