/*
    Copyright (C) 2016  PencilBlue, LLC

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
'use strict';

//dependencies
var NodeMailer = require('nodemailer');
var util       = require('./util.js');

module.exports = function EmailServiceModule(pb) {

    /**
     * Service for sending emails.
     *
     * @module Services
     * @class EmailService
     * @constructor
     * @param {String} [options.site=GLOBAL_SITE]
     * @param {String} [options.onlyThisSite=false]
     */
    function EmailService(options) {
        if (options) {
            this.site = pb.SiteService.getCurrentSite(options.site);
            this.onlyThisSite = options.onlyThisSite || false;
        }
    }

    /**
     *
     * @private
     * @static
     * @readonly
     * @property DEFAULT_SETTINGS
     * @type {Object}
     */
    var DEFAULT_SETTINGS = Object.freeze({
        from_name: pb.config.siteName,
        from_address: 'no-reply@sample.com',
        verification_subject: pb.config.siteName+' Account Confirmation',
        verification_content: '',
        template: 'admin/elements/default_verification_email',
        service: 'Gmail',
        host: '',
        secure_connection: 1,
        port: 465,
        username: '',
        password: ''
    });

    /**
     * Retrieves a template and sends it as an email
     *
     * @method sendFromTemplate
     * @param {Object}   options Object containing the email settings and template name
     * @param {Function} cb      Callback function
     */
    EmailService.prototype.sendFromTemplate = function(options, cb){
        var self = this;

        //TODO: Move the instantiation of the template service to the constructor so it can be injectable with all of the other context properties it needs.
        var ts   = new pb.TemplateService({ site: this.site });
        if (options.replacements) {
            for(var key in options.replacements) {
                ts.registerLocal(key, options.replacements[key]);
            }
        }
        ts.load(options.template, function(err, data) {

            var body = '' + data;
            self.send(options.from, options.to, options.subject, body, cb);
        });
    };

    /**
    * Uses an HTML layout and sends it as an email
    *
    * @method sendFromLayout
    * @param {Object}   options Object containing the email settings and layout
    * @param {Function} cb      Callback function
    */
    EmailService.prototype.sendFromLayout = function(options, cb){
        var self = this;
        var layout = options.layout;
        if (options.replacements) {
            for(var key in options.replacements) {
                layout.split('^' + key + '^').join(options.replacements[key]);
            }
        }
        self.send(options.from, options.to, options.subject, layout, cb);
    };

    /**
     * Sends an email
     *
     * @method send
     * @param  {String}   from    From name
     * @param  {String}   to      To email address
     * @param  {String}   subject Email subject
     * @param  {String}   body    Email content
     * @param  {Function} cb      Callback function
     */
    EmailService.prototype.send = function(from, to, subject, body, cb) {

        this.getSettings(function(err, emailSettings) {
            if (util.isError(err)) {
                throw err;
            }
            else if (!emailSettings) {
                err = new Error('No Email settings available.  Go to the admin settings and put in SMTP settings');
                pb.log.error(err.stack);
                return cb(err);
            }

            var options = {
                service: emailSettings.service,
                auth:
                {
                    user: emailSettings.username,
                    pass: emailSettings.password
                }
            };
            if (emailSettings.service == 'custom') {
                options.host = emailSettings.host,
                options.secureConnection = emailSettings.secure_connection,
                options.port = emailSettings.port;
            }
            var smtpTransport = NodeMailer.createTransport("SMTP", options);

            var mailOptions = {
                from: from || (emailSettings.from_name + '<' + emailSettings.from_address + '>'),
                to: to,
                subject: subject,
                html: body
            };

            smtpTransport.sendMail(mailOptions, function(err, response) {
                if (util.isError(err)) {
                    pb.log.error("EmailService: Failed to send email: ", err.stack);
                }
                smtpTransport.close();

                cb(err, response);
            });
        });
    };

    /**
     * Retrieves the email settings
     *
     * @method getSettings
     * @param {Function} cb Callback function
     */
    EmailService.prototype.getSettings = function(cb) {
        var self = this;
        var settingsService = pb.SettingServiceFactory.getServiceBySite(self.site, self.onlyThisSite);
        settingsService.get('email_settings', function(err, settings) {
            cb(err, util.isError(err) || !settings ? EmailService.getDefaultSettings() : settings);
        });
    };

    /**
     * Retrieves the default email settings from installation
     *
     * @method getDefaultSettings
     * @return {Object} Email settings
     */
    EmailService.getDefaultSettings = function() {
        return DEFAULT_SETTINGS;
    };

    //exports
    return EmailService;
};