4minitz/4minitz

const fs = require('fs');
const EJSON = require('mongodb-extended-json');

class ExpImpTopics {
    static get FILENAME_POSTFIX() {
        return '_topics.json';
    }

    static doExport (db, msID, userIDs) {
        return new Promise((resolve, reject) => {
            db.collection('topics')
                .find({parentId: msID})
                .toArray()
                .then(doc => {
                    if (doc) {
                        const topFile = msID + ExpImpTopics.FILENAME_POSTFIX;
                        fs.writeFileSync(topFile, EJSON.stringify(doc,null,2));
                        console.log('Saved: '+topFile + ' with '+doc.length+' topics');
                        resolve({db, userIDs});
                    } else {
                        return reject ('Unknown meeting series ID: '+ msID);
                    }
                });
        });
    }

    static doImport (db, msID, usrMap) {
        return new Promise((resolve, reject) => {
            const topFile = msID + ExpImpTopics.FILENAME_POSTFIX;
            let AllTopicsDoc = undefined;
            try {
                AllTopicsDoc = EJSON.parse(fs.readFileSync(topFile, 'utf8'));
                if (!AllTopicsDoc) {
                    return reject('Could not read topic file '+topFile);
                }
            } catch (e) {
                return reject('Could not read topic file '+topFile+'\n'+e);
            }

            // Replace old user IDs with new users IDs
            let topicIDs = [];
            for(let t=0; t<AllTopicsDoc.length; t++) {
                topicIDs.push(AllTopicsDoc[t]._id);
                AllTopicsDoc[t] = ExpImpTopics.patchUsers(AllTopicsDoc[t], usrMap);
            }


            return db.collection('topics')
                .deleteMany({ _id : { $in : topicIDs } })     // delete existing topics with same IDs
                .then(function (res) {
                    if (res.result && ! res.result.ok) {
                        console.log(res);
                    }
                    return db.collection('topics')
                        .insertMany(AllTopicsDoc)                         // insert imported minutes
                        .then(function (res) {
                            if (res.result.ok === 1 && res.result.n === AllTopicsDoc.length) {
                                console.log('OK, inserted '+res.result.n+' topics.');
                                resolve({db, usrMap});
                            } else {
                                reject('Could not insert topics');
                            }
                        });
                });
        });
    }


    static patchUsers(topicDoc, usrMap) {
        // patch topic-responsibles
        for (let i=0; topicDoc.responsibles&&i<topicDoc.responsibles.length; i++) {
            if (usrMap[topicDoc.responsibles[i]]) {  // may be "free text" user
                topicDoc.responsibles[i] = usrMap[topicDoc.responsibles[i]];
            }
        }
        // patch topic-actionitem-responsibles
        for (let i=0; topicDoc.infoItems&&i<topicDoc.infoItems.length; i++) {
            for (let j=0; topicDoc.infoItems[i].responsibles&&j<topicDoc.infoItems[i].responsibles.length; j++) {
                if (usrMap[topicDoc.infoItems[i].responsibles[j]]) {  // may be "free text" user
                    topicDoc.infoItems[i].responsibles[j] = usrMap[topicDoc.infoItems[i].responsibles[j]];
                }
            }
        }
        return topicDoc;
    }
}

module.exports = ExpImpTopics;