var mongoose = require('mongoose');
var nodemailer = require("nodemailer");
var chalk = require("chalk");
const cheerio = require('cheerio');

var db = require("kairoscope-db-models");
var SentMail = db.SentMail;

var send_mail = function(msg_data, id) {
    var content = add_link_tracking(msg_data.message, id)
    content = add_tracking_pixel(content, id);
    var mail_msg = {
        id: id,
        to: msg_data.to,
        from: msg_data.from,
        subject: msg_data.subject,
        html: content,
    }
    // create Nodemailer SES transporter
    var transporter = nodemailer.createTransport({
        host: process.env.AWS_SES_URL,
        port: 587,
        secure: false, // upgrade later with STARTTLS
        auth: {
          user: process.env.AWS_SES_SMTP_USERNAME,
          pass: process.env.AWS_SES_SMTP_PASSWORD
        }
    });
    transporter.sendMail(mail_msg, function (err, info) {
        if (err) {
            console.log("Error sending email");
            console.log(err);
            save_sent_email(mail_msg, undefined, false, false);
        } else {
            console.log(`Sent email ${chalk.italic(`\'${mail_msg.id}\'`)} successfully`);
            //console.log(info);
            save_sent_email(mail_msg, info, true, true);
        }
    });
}

var save_sent_email = function(email_msg, response_data, sent, delivered) {
    var new_sent_mail = new SentMail();
    if(response_data != undefined) new_sent_mail.sent_id = response_data.messageId;
    new_sent_mail.message_id = email_msg.id;
    new_sent_mail.to = email_msg.to;
    new_sent_mail.from = email_msg.from;
    new_sent_mail.subject = email_msg.subject;
    new_sent_mail.message = email_msg.html;
    new_sent_mail.sent = sent;
    new_sent_mail.delivered = delivered;
    new_sent_mail.save().then((sent_mail) => {
        console.log(`Saved email ${chalk.italic(`\'${sent_mail.message_id}\'`)} to database`);
    }).catch((error) => { reject(error); });
}

// Some checking to see if environment variables are set on statup and show errors if not
var check_env_variables = function() {
    var env = process.env;
    var e = `${chalk.red(`ERROR:`)}`;
    if(env.AWS_SES_URL != "" && env.AWS_SES_URL != undefined){
        console.log(`Delivery server URL: ${chalk.green(`\'${env.AWS_SES_URL}\'`)}`);
    } else {
        var v = `${chalk.yellow(`\'AWS_SES_URL\'`)}`;
        console.log(`${e} AWS SES URL is missing. To fix this, add ${v} to the environment variables.`);
    }
    var has_username = env.AWS_SES_SMTP_USERNAME != "" && env.AWS_SES_SMTP_USERNAME != undefined;
    var has_password = env.AWS_SES_SMTP_PASSWORD != "" && env.AWS_SES_SMTP_PASSWORD != undefined;
    if(has_username && has_password){
        console.log(`AWS SES authentication is set with username: ${chalk.italic(env.AWS_SES_SMTP_USERNAME)}`);
    } else {
        if(!has_username){
            var v = `${chalk.yellow(`\'AWS_SES_SMTP_USERNAME\'`)}`;
            console.log(`${e} AWS SES needs a username. Add ${v} to the environment variables.`);
        }
        if(!has_password){
            var v = `${chalk.yellow(`\'AWS_SES_SMTP_PASSWORD\'`)}`;
            console.log(`${e} AWS SES needs a password. Add ${v} to the environment variables.`);
        }
    }
    var has_tracking_url = env.TRACKING_URL != "" && env.TRACKING_URL != undefined;
    if(has_tracking_url) {
        console.log(`Tracking URL: ${chalk.green(`\'${env.TRACKING_URL}\'`)}`);
    } else {
        var v = `${chalk.yellow(`\'TRACKING_URL\'`)}`;
        console.log(`${e} The mail delivery service needs a tracking server URL. Add ${v} to the environment variables.`);
    }
}

var add_tracking_pixel = function(content, id) {
    var has_tracking_url = process.env.TRACKING_URL != "" && process.env.TRACKING_URL != undefined;
    if(has_tracking_url == false) return content;
    var s = `\n<img src="${process.env.TRACKING_URL}${id}/image.png">`;
    return content + s;
}

var add_link_tracking = function(content, id) {
    const html = cheerio.load(content);
    html('a').each( (index, link) => {
        var url = html(link).attr('href');
        var link_id = html(link).text();
        //link_id = link_id.replaceAll(" ", "-").replaceAll("/", "").replaceAll("\"", "").replaceAll(":", "").replaceAll("'", "");
        var new_url = `${process.env.TRACKING_URL}${id}/redirect?url=${url}&link=${link_id}`;
        html(link).attr("href", new_url);
     });
     return html.html();
}

module.exports.send_mail = send_mail;
module.exports.save_sent_email = save_sent_email;
module.exports.check_env_variables = check_env_variables;