/**
 * Support utilities for notifying the admin of various cases
 */
'use strict';

const Q = require('q');
const _ = require('lodash');
const mailer = require(global.pathPrefix + 'mailer.js');
const templates = require(global.pathPrefix + '../utils/templates.js');
var debug = require('debug')('utils:adminNotifier');

/**
 * Exports from this module
 */
module.exports = {
    notifyIdentityCheckIssue: notifyIdentityCheckIssue,
    notifyCredits: notifyCredits
};

/**
 * Address that all notifications should be sent to
 */
const NOTIFICATION_EMAIL = 'admin@comcarde.com';

/**
 * Table of credit limits to send emails
 */
const SERVICES_TABLE = {
    tracesmart: {
        limit: 100,
        lastReport: Number.MAX_VALUE,
        reportStep: 10
    },
    txtlocal: {
        limit: 100,
        lastReport: Number.MAX_VALUE,
        reportStep: 10
    }
};

/**
 * Notifies admin that there is an identity check issue to investigate
 *
 * @param {Object} client   - the client object (updated with the latest identify results)
 *
 *@return {Promise}         - promise for the result of sending the email
 */
function notifyIdentityCheckIssue(client) {
    const caller = 'notifyIdentityCheckIssue';
    //
    // Get the email parameters
    //
    var params = {
        ClientID: client.ClientID,
        ProfileURL: client.KYC[0].ProfileURL
    };

    //
    // Render the email
    //
    var htmlEmail = templates.render('adminNotifier/identity_check.pug', params);
    var subject = 'Manual Identity Check Needed';

    //
    // Pass it to the mailer to send (wrapped in a Q.nfcall to turn it into
    // a promise).
    // When the promise completes, call any callback defined
    //
    return Q.nfcall(mailer.sendEmail, '', NOTIFICATION_EMAIL, subject, htmlEmail, caller);
}

/**
 * Used to notify the admin if credits for a service are getting low.
 * The meaning of "getting low" is defined in here, so callers just call this
 * every time, and this system sends or does not send an email as neccessary.
 *
 * @param {String} name     - the name of the service the credits are for
 * @param {Number} value    - the number of credits remaining
 *
 * @return {Promise}        - promise for the result of sending the notification
 */
function notifyCredits(name, value) {
    debug('notifyCredits: ', name, value);

    let service = SERVICES_TABLE[name];
    if (_.isUndefined(service)) {
        /**
         * Use a default service that will always report - should get fixed quickly!
         */
        service = {
            limit: Number.MAX_VALUE,
            lastReport: Number.MAX_VALUE,
            reportStep: 0
        };
    }

    /**
     * Check if we need to send a notification
     */
    let nextReport = service.lastReport - service.reportStep;
    if (
        value > service.limit || // Above threshold
        (service.lastReport > value && value > nextReport)// Between reporting steps
    ) {
        /**
         *  Don't need to send a report
         */
        return Q.resolve();
    }

    /**
     * DO need to send a report
     */
    const caller = 'notifyCredits';
    //
    // Get the email parameters
    //
    var params = {
        Service: name,
        CreditsRemaining: value,
        CreditsLimit: service.limit
    };

    //
    // Render the email
    //
    var htmlEmail = templates.render('adminNotifier/credits_low.pug', params);
    var subject = '[' + name + '] Low Credits!';

    //
    // Pass it to the mailer to send (wrapped in a Q.nfcall to turn it into
    // a promise).
    // When the promise completes, call any callback defined
    //
    return Q.nfcall(mailer.sendEmail, '', NOTIFICATION_EMAIL, subject, htmlEmail, caller)
        .then(() => {
            /**
             * Successfully sent the email, so updated the value we last reported at
             */
            service.lastReport = value;
        });
}