script.js

const fs = require('fs');
const readlines = require('n-readlines');
const teams = require('./input/teams.json').teams;

people = {};
let line;
let liner = new readlines('input/people.csv');

let ignoreTeams = [8,9];

while (line = liner.next()) {
    let parts = line.toString('utf8').split(',');
    let id = parts[2]; // first name with first char of last name if necessary
    let team = Number(parts[0]);
    people[id] = {
        "in_team": team,
        "in_corona_group": teams.filter(t => t.id === team).map(t => t.group)[0],
        "id": id,
        "name": parts[3],
        "gender": parts[4],
        "discipline": parts[5].substr(0, parts[4].length - 1), // strip away new line character
        "already_met_with": [],
        "ignore": ignoreTeams.includes(team),
        "testcount": 0
    };
}

const importBlockers = csvFile => {
    liner = new readlines(csvFile);
    while (lineRaw = liner.next()) {
        line = lineRaw.toString('utf8');
        if (!line || line.length === 0 || line.charAt(0) === '#') {
            continue;
        }
        let parts = line.split(',');
        for (let i = 0; i < parts.length; i ++) {
            let idSelf = parts[i];
            for (let j = i + 1; j < parts.length; j ++) {
                let idOther = parts[j];
                people[idSelf].already_met_with.push(idOther);
                people[idOther].already_met_with.push(idSelf);
            }
        }
    }
};

importBlockers('input/blockers/other.csv');
importBlockers('input/blockers/lunch1.csv');
importBlockers('input/blockers/lunch2.csv');
importBlockers('input/blockers/lunch3.csv');
importBlockers('input/blockers/rooms.csv');
importBlockers('input/blockers/lunch4.csv');
importBlockers('input/blockers/lunch5.csv');
importBlockers('input/blockers/lunch6.csv');
importBlockers('input/blockers/lunch7.csv');

const getRandomElementFromArray = array => { // min and max included
    let min = 0;
    let max = array.length - 1;
    return array[Math.floor(Math.random() * (max - min + 1) + min)]
};

let ungroupedPeople = Object.keys(people).filter(id => !people[id].ignore);
let groups = [];
const groupsMustBeSameGender = false;

const findSuitableAdditionToGroup = (peopleAlreadyInGroup) => {
    let suitablePeople = [];
    for (let i = 0; i < ungroupedPeople.length; i++) {
        let candidate = people[ungroupedPeople[i]];
        let candidateIsSuitable = true;
        for (let j = 0; j < peopleAlreadyInGroup.length; j++) {
            let pInGroup = people[peopleAlreadyInGroup[j]];
            if (!pInGroup ||
                candidate.id === pInGroup.id ||
                candidate.already_met_with.includes(pInGroup.id) ||
                candidate.in_team === pInGroup.in_team ||
                candidate.in_corona_group !== pInGroup.in_corona_group ||
                (groupsMustBeSameGender && candidate.gender !== pInGroup.gender)
            ) {
                candidateIsSuitable = false;
            }
        }
        if (candidateIsSuitable) {
            suitablePeople.push(candidate.id);
        }
    }
    return getRandomElementFromArray(suitablePeople);
};

const n = Object.keys(people).length;
// const groupSize = 3;
let groupSizes = [];
const groupsOf2 = 20;
const groupsOf3 = 0;
let checksum = 0;
for (let i = 0; i < groupsOf2; i ++) {
    groupSizes.push(2);
    checksum += 2;
}
for (let i = 0; i < groupsOf3; i ++) {
    groupSizes.push(3);
    checksum += 3;
}
console.log(groupSizes, checksum);

for (let j = 0; j < groupSizes.length; j ++) {
    let groupSize = groupSizes[j];
    let newGroup = [getRandomElementFromArray(ungroupedPeople)];
    for (let k = 0; k < groupSize - 1; k++) {
        newGroup.push(findSuitableAdditionToGroup(newGroup));
    }
    groups.push(newGroup);
    newGroup.map(id => ungroupedPeople.splice(ungroupedPeople.indexOf(id), 1));
}

// pretty print matches
let csvContent = '';
for (let i = 0; i < groups.length; i++) {
    let group = groups[i];
    let csvRow = '';
    let printRow = '';
    for (let j = 0; j < group.length; j++) {
        let groupMember = group[j];
        csvRow += groupMember + ',';
        let name = people[groupMember] ? people[groupMember].name : 'UNDEFINED';
        printRow += name + " & ";
    }
    console.log(printRow.substring(0, printRow.length - 3));
    csvContent += csvRow.substring(0, csvRow.length - 1) + '\n';
}

// write them out as next lunch.csv
fs.writeFile('input/blockers/lunch8.csv', csvContent, err => {});

// TODO via @lambdapioneer: try bipartite matching, max flow, Ford-Fulkerson.
//      Could be great to visualize a slowed-down match-making for everyone to
//      see it happening at a specified time and URL

// TODO @jerdesign suggested to add a factor that reduces the likelihood of getting
//      matched with people that ones teammates already met with. One way to achieve
//      achieve this, could be to add people that ones teammates have NOT met with
//      already multiple times in the suitablePeople-array within findSuitableAdditionToGroup()

// TESTS ---------------------------------------------------------

for (let i = 0; i < groups.length; i++) {
    let group = groups[i];
    for (let j = 0; j < group.length; j++) {
        let groupMember1 = people[group[j]];
        if (groupMember1 === undefined) {
            continue;
        }
        groupMember1.testcount += 1;
        for (let k = j + 1; k < group.length; k++) {
            let groupMember2 = people[group[k]];
            if (groupMember2 === undefined) {
                continue;
            }
            if (groupMember1.in_team === groupMember2.in_team ||
                groupMember1.already_met_with.includes(groupMember2.id) ||
                groupMember2.already_met_with.includes(groupMember1.id) ||
                groupMember1.in_corona_group !== groupMember2.in_corona_group ||
                (groupsMustBeSameGender && groupMember1.gender !== groupMember2.gender)
            ) {
                console.log("ERROR: " + groupMember1.id + ' and ' + groupMember2.id + ' in group ' + group);
            }
        }
    }
}

let peopleIDs = Object.keys(people);
let report = '';
for (let i = 0; i < peopleIDs.length; i++) {
    let person = people[peopleIDs[i]];
    if (person.testcount !== 1) {
        report += person.id + ', ';
    }
}
if (report) {
    console.log('\n' + (report.split(',').length - 1) + ' people not in a group: ' + report.substring(0, report.length - 2));
}

// COMBINATORICS ---------------------------------------------------------

/*
let allPairs = [];
for (let i = 0; i < peopleIDs.length; i++) {
    for (let j = i + 1; j < peopleIDs.length; j++) {
        let p1 = people[peopleIDs[i]];
        let p2 = people[peopleIDs[j]];
        allPairs.push([p1.id, p2.id]);
    }
}
console.log("\n\n" + allPairs.length + " groups of 2 with " + peopleIDs.length + " people");
*/