pipeline = [{
    $match: {
        event: 'sample_event',
    }
}, {
    $project: {
        _id: false,
        uuid: '$properties.distinct_id',
        time: '$properties.time'
    }
}, {
    $group: {
        _id: {
            year: {
                $year: '$time'
            },
            month: {
                $month: '$time'
            },
            day: {
                $dayOfMonth: '$time'
            },
            uuid: '$uuid'
        }
    }
}, {
    $group: {
        _id: {
            year: '$_id.year',
            month: '$_id.month',
            day: '$_id.day'
        },
        value: { $sum: 1 }
    }
}, {
    $sort: {
        '_id.year': 1,
        '_id.month': 1,
        '_id.day': 1
    }
}, {
    $project: {
        _id: {
            $concat: [
                { $substr: ['$_id.year', 0, 4] },
                '-',
                {
                    $cond: [
                        { $lte: [ '$_id.month', 9 ] },
                        { $concat: [
                            '0',
                            { $substr: [ '$_id.month', 0, 2 ] }
                        ]},
                        { $substr: [ '$_id.month', 0, 2 ] }
                    ]
                },
                '-',
                {
                    $cond: [
                        { $lte: [ '$_id.day', 9 ] },
                        { $concat: [
                            '0',
                            { $substr: [ '$_id.day', 0, 2 ] }
                        ]},
                        { $substr: [ '$_id.day', 0, 2 ] }
                    ]
                },
            ]
        },
        date: new Date('$_id.year', '$_id.month', '$_id.day'), // errorrrr
        value: 1
    }
}, {
    $out: 'output_collection'
}];