"use strict";
const { URL } = require("url");

const AppConstants = require("./app-constants");

const nodemailer = require("nodemailer");
const hbs = require("nodemailer-express-handlebars");

const HBSHelpers = require("./template-helpers/");
const mozlog = require("./log");


const log = mozlog("email-utils");

const hbsOptions = {
  viewEngine: {
    extname: ".hbs",
    layoutsDir: __dirname + "/views/layouts",
    defaultLayout: "default_email",
    partialsDir: __dirname + "/views/partials",
    helpers: HBSHelpers.helpers,
  },
  viewPath: __dirname + "/views/layouts",
  extName: ".hbs",
};

// The SMTP transport object. This is initialized to a nodemailer transport
// object while reading SMTP credentials, or to a dummy function in debug mode.
let gTransporter;

const EmailUtils = {
  async init(smtpUrl = AppConstants.SMTP_URL) {

    // Allow a debug mode that will log JSON instead of sending emails.
    if (!smtpUrl) {
      log.info("smtpUrl-empty", { message: "EmailUtils will log a JSON response instead of sending emails." });
      gTransporter = nodemailer.createTransport({jsonTransport: true});
      return Promise.resolve(true);
    }

    gTransporter = nodemailer.createTransport(smtpUrl);
    const gTransporterVerification = await gTransporter.verify();
    gTransporter.use("compile", hbs(hbsOptions));
    return Promise.resolve(gTransporterVerification);
  },


  sendEmail(aRecipient, aSubject, aTemplate, aContext) {
    if (!gTransporter) {
      return Promise.reject("SMTP transport not initialized");
    }

    const emailContext = Object.assign({
      SERVER_URL: AppConstants.SERVER_URL,
    }, aContext);
    return new Promise((resolve, reject) => {
      const emailFrom = AppConstants.EMAIL_FROM;
      const mailOptions = {
        from: emailFrom,
        to: aRecipient,
        subject: aSubject,
        template: aTemplate,
        context: emailContext,
        headers: {
          "x-ses-configuration-set": AppConstants.SES_CONFIG_SET,
        },
      };

      gTransporter.sendMail(mailOptions, (error, info) => {
        if (error) {
          reject(error);
          return;
        }
        if (gTransporter.transporter.name === "JSONTransport") {
          log.info("JSONTransport", { message: info.message.toString() });
        }
        resolve(info);
      });
    });
  },

  appendUtmParams(url, campaign, content) {
    const utmParameters = {
      utm_source: "fx-monitor",
      utm_medium: "email",
      utm_campaign: campaign,
      utm_content: content,
    };
    for (const param in utmParameters) {
      url.searchParams.append(param, utmParameters[param]);
    }
    return url;
  },

  getReportSubject(breaches, req) {
    if (breaches.length === 0) {
      return req.fluentFormat("email-subject-no-breaches");
    }
    return req.fluentFormat("email-subject-found-breaches");
  },

  getEmailCtaHref(emailType, campaign, subscriberId=null) {
    const subscriberParamPath = (subscriberId) ? `/?subscriber_id=${subscriberId}` : "/";
    const url = new URL(subscriberParamPath, AppConstants.SERVER_URL);
    return this.appendUtmParams(url, campaign, emailType);
  },

  getVerificationUrl(subscriber) {
    let url = new URL(`${AppConstants.SERVER_URL}/user/verify`);
    url.searchParams.append("token", encodeURIComponent(subscriber.verification_token));
    url = this.appendUtmParams(url, "verified-subscribers", "account-verification-email");
    return url;
  },

  getUnsubscribeUrl(subscriber, emailType) {
    let url = new URL(`${AppConstants.SERVER_URL}/user/unsubscribe`);
    const token = (subscriber.hasOwnProperty("verification_token")) ? subscriber.verification_token : subscriber.primary_verification_token;
    const hash = (subscriber.hasOwnProperty("sha1")) ? subscriber.sha1 : subscriber.primary_sha1;
    url.searchParams.append("token", encodeURIComponent(token));
    url.searchParams.append("hash", encodeURIComponent(hash));
    url = this.appendUtmParams(url, "unsubscribe", emailType);
    return url;
  },
};

module.exports = EmailUtils;