smpreview_iota.js

'use strict';

const Iota=require('iota')();
const MongoModels=require('mongo-models');

var smpreview_iota = {_ids: {}};
var smpreview_subject = 'Simple preview image for socal network query, facebook, tweet';
var smpreview_description = 'Snapshot png image filelink saved in Cloudinary';

async function path(parentId) {
    var data = [];
    return new Promise(async (ok, ko) => {
        try {
            data=await Iota.findOne({_id:Iota.ObjectID(parentId)});
            return ok(data);
            }
        catch (error) {
            console.error("sIota.path() caught error", error);
            return ko(error)
        }
    })
}
function init(){
    return new Promise(async (ok,ko)=>{
        try{
            await Iota.connectInit();
            return ok();
        }
        catch(err){
            ko(err);
        }
    })
}

function disconnect(){
    MongoModels.disconnect();
}
function update_smpreview(parent, iUrl, site){
    var data = [];
    return new Promise(async (ok,ko)=>{
        try{
//          Per the discusion, all socialpreview images are kept. When generating social preview, be sure to select the lastest one.
//          in the future, need one housekeeper to archive all Cloudinary old image and delete DB entries. 
//          data=await Iota.findOneAndDelete(
//                {
//                    $and: [
//                            {parentId: pId},
//                            {"component.component": "socialpreview"}
//                        ]
//                }
//            )
            const result = await Iota.insertOne(
                {
                    parentId: parent._id.toString(), 
                    subject: 'Social Media Preview: '+parent.subject, 
                    description: `a social media preivew for taken from ${site}`, 
                    component: {component: 'socialpreview', imgUrl: iUrl}
                }
            );
            if(result && result.length===1)
                ok(result[0]);
            else {
                const msg=`unexpected number of results received ${results.length}`
                logger.error(msg)
                ko(new Error(msg));
            }
            return ok();
        }
        catch(err){
            ko(err);
        }
    })

}

function get_parentId4smpreview() {
    var data = [];
    return new Promise(async (ok,ko)=>{
        try{
            var lastSocialPreviews = await Iota.aggregate([
                { $match: { 'component.component': 'socialpreview' } },
                { $sort: { _id: -1 } },
                 {$limit: 1}
            ])
            if(lastSocialPreviews.length) {
                let lastSocialPreview=lastSocialPreviews[0]._id;                   
                data = await Iota.aggregate([
                    { $match: {'component.component': 'MergeParticipants', parentId: {$exists: true}, _id: {$gt: lastSocialPreview} } },
                    { $sort: { _id: -1 } },
                    { $group: { _id: '$userId', latest: { $first: '$$ROOT' } } },
            //      { $limit: maxParticipants },
                    { $replaceRoot: { newRoot: '$latest' } },
                ]);
            } else {
                data = await Iota.aggregate([
                    { $match: {'component.component': 'MergeParticipants', parentId: {$exists: true}}},
                    { $sort: { _id: -1 } },
                    { $group: { _id: '$parentId', latest: { $first: '$$ROOT' } } },
            //      { $limit: maxParticipants },
                    { $replaceRoot: { newRoot: '$latest' } },
                ]);               
            }
            return ok(data);
        }
        catch(err){
            ko(err);
        }
    })
}

smpreview_iota.connectInit=init;
smpreview_iota.disconnect=disconnect;
smpreview_iota.path=path;
smpreview_iota.update_smpreview=update_smpreview;
smpreview_iota.Get_parentId4simprview=get_parentId4smpreview;

module.exports=smpreview_iota;