import * as functions from 'firebase-functions';
import * as admin from 'firebase-admin';
import MailchimpApi = require('mailchimp-api-v3');
import md5 = require('crypto-js/md5');

const CRON_SCHEDULE = '* * * * *';

export const cronMailchimp = functions.region('europe-west1').pubsub
    .schedule(CRON_SCHEDULE).onRun(async context => {
        const { audience, apikey } = functions.config().mailchimp;
        if (!audience || !apikey) {
          throw new Error(`Missing mailchimp config! Current config is ${JSON.stringify(functions.config(), null, 2)}`);
        }

        const mailchimpApi = new MailchimpApi(apikey);
        const userRefs = await admin.firestore().collection('users').listDocuments();
        for (const userRef of userRefs) {
            const userDoc = await userRef.get();
            const user = userDoc.data();
            console.log(`mailchimp.ts - handling user ${userRef.id} with email ${user.email}`);

            try {
                await patchContact(mailchimpApi, audience, user);
                console.log(`mailchimp.ts - user updated!`, );
            } catch (e) {
                console.log(`mailchimp.ts - catched updated error (probably contact does not exist)`, e);
                try {
                    await createContact(mailchimpApi, AUDIENCE_ID, user);

                    console.log(`mailchimp.ts - user created!`, );
                } catch (e) {
                    console.error(`mailchimp.ts - failed to create contact!`, e);
                }
            }
        }
    })

const createContact = async (mailchimpApi, audienceId, user) => {
    const body = {
        email_address: user.email,
        status: "subscribed",
        merge_fields: {
            FNAME: user.name,
            LNAME: user.surname
        }
    };

    return mailchimpApi.post(`/lists/${audienceId}/members/`, body);
}

const patchContact = async (mailchimpApi, audienceId, user) => {
    const body = {
        merge_fields: {
            FNAME: user.name,
            LNAME: user.surname
        }
    };
    const memberId = md5(user.email.toLowerCase());

    return mailchimpApi.patch(`/lists/${audienceId}/members/${memberId}`, body);
}